The resorption of the residual alveolar ridges is a chronic and continuous process of bone remodeling. The aim of this study was to analyse the rate of residual ridge resorption at different sites in the both jaws in complete denture wearers, through a five-year period of denture wearing. Residual ridge changes were measured on successive lateral cephalograms at 5 measurement points of the maxilla and the mandible. The first lateral radiograph was obtained at the delivery of complete dentures. The second lateral cephalogram was obtained after five years of denture wearing. Measurements were performed using a calibrated grid. The results of this study showed the existence of a significant alveolar ridge resorption at all five measurement points of the maxilla and the mandible. The observed variables, such as body mass index and the night time denture wearing had no significant influence on the rate of residual alveolar ridge resorption (p > 0.05). The duration of edentulousness had a significant influence on the rate of residual ridge resorption with significantly higher amounts of alveolar bone height decrease in those patients who had lost the last remaining teeth more recently. PMID:20977102

Background Lack of sufficient alveolar bone height or width is one of the most frequent problems in the dental rehabilitation of the edentulous patient. Methods A prospective study to evaluate the efficacy of an endosseous alveolar distractor (LEADTM) in managing residual alveolar ridge resorption was carried out. The complications related to the surgical procedure and the quantitative changes in the regenerate over a 6 month period following distraction were studied in 13 cases with alveolar ridge atrophy. Result Desired ridge augmentation was achieved in 11 cases. In 2 cases the distraction failed. Some unusual complications were encountered. Conclusion The LEAD? alveolar distractor produces consistent augmentation of the alveolar bone but is confronted with stability issues.

Abstract Patients presenting with severe resorption of the residual alveolar ridges are relatively common today in both private practices and teaching institutions. The severely resorbed mandibular ridge is more challenging to impress than is the maxillary ridge. Accurately capturing the denture-bearing surface in its entirety is crucial to providing the patient with a functionally successful prosthesis. This article presents a technique to overcome the difficulties encountered in impressing the severely resorbed mandibular ridge using elastomeric impression materials and a modified special custom tray.

Background Alveolar bone is usually resorbed after the loss of a tooth. As the buccal bony plate of the alveolar bone is thin compared to the palatal or the lingual bony plate, the bone resorption rate is higher on the buccal side. If a patient is partially edentulous, vertical bone resorption is restricted by the adjacent teeth. In such a case, the residual alveolar ridge becomes thin and narrow. As a result, a veneer graft is required. Case report Two patients received a total of two implants with a modified technique. The modified technique is described in which the implant hole is made in both the mandibular ramus and the recipient site. Autogenous bone was taken from the mandibular ramus as a partial-thickness graft. The grafted bone was adapted to an installed dental implant and used...

When performing a tooth extraction, imminent collapse of the tissue by resorption and remodeling of the socket is a natural occurrence. The procedure for the preservation of the alveolar ridge has been widely described in the dental literatures and aims to maintain hard and soft tissues in the extraction site for optimal rehabilitation either with conventional fixed or removable prosthetics or implant-supported prosthesis. PMID:15142088

Tooth loss is followed by a natural bone resorption process that often leads to defects in the alveolar ridge, making the installation of dental implants unfeasible. Correction of such bone defects, especially loss of height of the ridge or associated loss of thickness, is a great challenge to dental surgeons. The technique of segmental osteotomy accompanied by interpositional bone grafting has been shown to be a viable option for addressing the problem. This report describes a successful application of the technique in the treatment of vertical dimension deficiency in the posterior maxillary region. Four months after graft surgery, 3 implants were successfully placed in accordance with the original reverse planning.

A various amount of alveolar ridge resorption is likely to occur after tooth extraction, making it difficult to restore the missing teeth with either endosseous dental implants or prosthodontics approaches. It is commonly thought that the bone resorption is due to the absence of the mechanical stimulation from the occlusal force. However, regulation of the bone mass is a complex homeostatic system involved in hormonal, paracrine/autocrine, mechanical and neuronal nature. Studies have shown that the central and peripheral nervous system play an important role in bone remodeling. The hypothalamus integrates peripheral and central signals, and sends efferent hormonal and neuronal signals in response to stimulation. Numerous neuropeptides detected in the bone marrow have effect on the osteoblast and osteoclast. After tooth extraction, great loss of the axons is observed in the edentulous bone. So we speculate that innervation in the alveolar bone regulates the bone resorption in edentulous area. Methods to promote the nerve regeneration are expected to prevent the jaw bone resorption. The hypothesis also implies that after the placement of the oral implant the abundant nerves in the alveolar bone can increase the bone healing ability and long term survival rate of the implant. PMID:18514432

Objective. Intensive mechanical stress and/or inflammation are known to induce alveolar bone resorption. This study investigated whether a distribution of mechanical stress would reduce residual ridge resorption or improve ischaemia. Design.Thirty rats were divided into six experimental groups (n = 5). The control group received no intentional stimulation, but rats in the experimental groups wore denture stimulators made of acrylic resin or a soft lining material. The stimulator transmitted masticatory pressure to the rats? palates for four weeks. The four types of soft lining materials investigated in this study dispersed the applied pressure, with compressive stress ranging from 20.8 to 90.8 kPa. Volumes of blood flow and bone resorption of denture foundations were measured every week fo...

Alveolar ridge resorption occurs after tooth extraction and has the potential to either complicate implant placement or impair the final esthetic result. Techniques to preserve natural bone and soft tissue contours are of great interest to clinicians and patients because even subtle postextraction buccal plate resorption may have significant clinical effects, particularly in the esthetic zone. Buccal plate augmentation (BPA) is a novel approach for ridge preservation aiming to avoid recession of the facial wall of the socket without interfering with the natural healing mechanism of the extraction socket. It consists of placement of bone graft material over an intact buccal plate, underneath the soft tissues in a surgically created pouch with an aim to maintain or augment the soft tissue es...

Despite being considered noncritical size defects, extraction sockets often require the use of bone grafts or bone graft substitutes in order to facilitate a stable implant site with an aesthetically pleasing mucosal architecture and prosthetic reconstruction. In the present study, the effect of novel TiO2 scaffolds on dimensional ridge preservation was evaluated following their placement into surgically modified extraction sockets in the premolar region of minipig mandibles. After six weeks of healing, the scaffolds were wellintegrated in the alveolar bone, and the convex shape of the alveolar crest was preserved. The scaffolds were found to partially preserve the dimensions of the native buccal and lingual bone walls adjacent to the defect site. A tendency towards more pronounced vertical ridge resorption, particularly in the buccal bone wall of the nongrafted alveoli, indicates that the TiO2 scaffold may be used for suppressing the loss of bone that normally follows tooth extraction. PMID:2094653

Abstract Objective: The aim of this study was a radiographic mesiodistal analysis of the shape of the bone crest 3 months after tooth removal. Material and methods: One hundred single tooth extractions were performed on 100 patients because of orthodontic or prosthetic causes. Bite blocks were used for two radiographs: one on the day of extraction and the other after healing of the socket, 3 months later. These X-rays were used to determine: (1) the most apical distance of alveolar ridge resorption, with baseline as the line between bone-to-teeth contact (the greatest distance in bone resorption height) and (2) the mesiodistal distance (MDD) and mesial and distal angles arising after bone tissue modeling. Results: Significant differences (P<0.05) emerged between the MDDs of multiple- [8 mm...

Abstract in portuguese Esta pesquisa constatou a prevalência dos tipos de rebordos residuais no sentido ântero-posterior em extremidades livres inferiores, além de correlacionar alguns fatores que possam influenciar as suas reabsorções. Para isso, utilizamos radiografias periapicais e dados individuais colhidos na amostra de 64 hemiarcos; foram obtidas 2 radiografias de cada área de extremidade livre e, a partir de traçados, determinamos os ângulos formados pela reabsorção na altura d (more) o 1º molar inferior. Podemos constatar que: 1º) a grande maioria de inclinação encontrada foi de rebordos descendentes para distal; 2º) a média de angulação foi maior para usuários de prótese parcial removível inferior; 3º) os resultados sugeriram existir influência do tipo de arco antagônico superior na inclinação dos rebordos inferiores; 4º) observou-se aumento de inclinação quando os segundos pré-molares inferiores eram os dentes adjacentes ao espaço protético; e 5º) não foram encontradas correlações significantes entre idade, sexo e reabsorção do rebordo residual. Abstract in english This study observed the prevalence of different types of residual ridge inclination in free-ends of mandibles and reported possible correlative factors that may affect resorption. For this purpose, periapical radiographs and individual data collected from a sample of 64 hemiarches were used. Two radiographs were taken of each free-end, and tracing was employed to determine the angles formed by the resorption configuration in the area of the 1st mandibular molar. The follo (more) wing conclusions were drawn: 1) the great majority of alveolar ridges were distally descending; 2) the average angle was wider for users of mandibular removable partial dentures; 3) the results obtained suggest that the type of opposing maxillary arch affects the inclination of mandibular ridges; 4) greater inclination was observed when the 2nd bicuspids of the mandible were the abutment teeth; 5) no significant correlation was established between age, sex and residual ridge resorption.

Posterior denture teeth wear faster than the anterior teeth, causing occlusal prematurities and loss of vertical dimension of occlusion. The loss of vertical dimension of occlusion lays more stress on the anterior alveolar ridge, which in turn increases the rate of residual ridge resorption and causes loss of alveolar ridge height in the anterior segment and compromises esthetics. Hence it is important for the clinician to choose acrylic resin teeth with high wear resistance. The objective of the study is to investigate and compare the wear resistance of three different commercially available acrylic resin denture teeth. 60 specimens were tested for wear resistance in terms of loss of weight and loss in volume on a wear and friction monitor for 5,000 cycle wear periods (total of 10,000 cycles) under a 0.20 kg load. Statistical analysis used: The findings were analyzed using one way analysis of variance (ANOVA) and Tukey HSD test. Comparison of weight loss and volume loss between Surana ultradent, Premadent and Dentek showed highly significant difference, Surana ultraddent having better wear resistance. Surana ultradent acrylic resin denture had highest wear resistance amongst the three groups of tested samples. PMID:21886405

Abstract The purpose of this review and summary is to focus the clinician's attention on existing potential limitations regarding the management of edentulism. The current published data and opinions concerning the need for treating edentulism, the quality of dentures, related morbidity, and alternative or related therapeutics (e.g., dental implants) suggest there are opportunities for improvement in the treatment of the edentulous population. This may be achieved by adopting a broader therapeutic strategy focused not solely on technical aspects of an oral prosthesis. Instead, a wider array of clinical features of the edentulous patient should be addressed. A contemporary strategy may include concerns for prevention of tooth loss, evaluation of residual alveolar ridge resorption, and relat...

BACKGROUND: Loss of teeth results in marked qualitative and quantitative alterations of the alveolar process at the edentulous site. It was observed that a graft comprised of bovine bone mineral placed in the fresh extraction socket delayed tissue modeling, but preserved the dimension of the ridge at edentulous sites. OBJECTIVE: To analyze the influence of a biphasic synthetic graft on tissue modeling and remodeling during healing of extraction wounds. MATERIAL AND METHODS: Five beagle dogs were used. Two premolars in the maxilla and two in the mandible were included. Full thickness flaps were elevated and the distal roots were removed. An alloplastic graft (BPCAP; ?-TCP core coated with nanocrystalline biomimetic hydroxyapatite) embedded in porcine collagen was placed to fill the fresh extraction socket of the premolar sites. Flaps were replaced to cover the entrance of the extraction sockets during early healing. The extraction and grafting procedures were scheduled to allow for the study of 1, 2, and 3 months socket healing. The biopsies from the maxillary sites were decalcified, embedded in paraffin, and stained to allow the study of various aspects of hard tissue formation. The biopsies from the mandibular sites were processed for ground sectioning and used to evaluate alterations of ridge dimensions after 3 months of socket healing. RESULTS AND CONCLUSION: It was documented that the biphasic alloplastic graft did not undergo marked resorption during tissue modeling and remodeling, but allowed large amounts of bone to form within the post-extraction site. Grafting the experimental sites with this biomaterial furthermore counteracted ridge resorption that otherwise occurs following tooth extraction. PMID:22804845

The absence of posterior occlusal contacts may result in increased anterior occlusal contacts and forces between natural mandibular dentition and artificial maxillary dentition. The impact of natural mandibular anterior teeth on the development of hypermobile tissues in the anterior part of the edentulous maxillary alveolar ridge was investigated in this study. The study group consisted of 410 patients with maxillary complete dentures and various mandibular dentitions from seven rest homes in Istanbul. The data; including hypermobile tissue in the anterior part of the maxilla, occlusal relationship, nocturnal wear, denture age, and duration of the maxillary full edentulism period were recorded. A chi-square test was performed to analyze the effects of following data: Existence of mandibular anterior teeth, poor adaptation of the dentures, nocturnal wear, types of occlusal contacts, and gender, on the resorption of the anterior part of the maxilla. To examine the effects of the presence of anterior mandibular teeth and early maxillary edentulism on bone resorption in the anterior part of the maxilla, a logistic regression analysis was performed. The results reveal that patients with edentulous maxilla and natural mandibular anterior teeth are approximately twice more likely to show risk of hypermobile tissue in the anterior part of the maxilla than are full edentulous patients. Further, edentulous periods exceeding 30 years in maxilla seem to increase this risk approximately 4 times. PMID:21669467

Abstract Among alveolar ridge augmentation techniques, a ridge-split procedure demonstrates many benefits, including lack of a second donor surgical site, the risk of inferior alveolar nerve injury, additional pain and swelling, etc. Lateral bone augmentation through the ridge-split works at its best in the localized lateral bony defect intended for a one or two implants and where the ridge is vertically intact. In this article, authors present a detailed description of the implant-driven technique of alveolar ridge-split procedure in small and large bone deficiencies, in maxilla and mandible, supplemented by multiple photographs, accentuating the need for a careful manipulation of the thin ridge based on knowledge of precise surgical principles. A need for the training and operator's experience to perform this type of alveolar bone augmentation is emphasized. PMID:22663093

Severely atrophic ridges provide decreased retention, support, and stability and pose a clinical challenge to the success of complete denture prostheses. Extreme ridge resorption also increases the interridge distance. Restoration of the vertical dimension and esthetics thus demands increased height of the prosthesis and in turn leads to an increase in prosthesis weight. Reducing the weight of the denture enhances stability and retention and reduces further resorption of the jaw, thereby favoring the prognosis of the denture. This report describes the rehabilitation of an edentulous patient with resorbed maxillary and mandibular ridges and an increased interridge distance using simplified techniques of fabricating hollow dentures. PMID:22985439

Purpose: To assess the influence of mandibular residual ridge resorption (RRR) on objective masticatory measures of two occlusal schemes: lingualized occlusion (LO) and fully bilateral balanced articulation (FBBA).Methods: The enrolled patients (n = 22) were randomly allocated one set of complete dentures with either LO or FBBA. Maximum occlusal force, masticatory performance (by the MPI), and mandibular movements were measured at 3- and 6-month follow-ups. Mandibular RRR was assessed as the sum of the mandibular bone height at the midline, first premolar region, and least vertical height region, and from the mental foramen to the alveolar crest, measured on panoramic radiographs; the treatment groups were subclassified into severe or moderate RRR subgroups by the value of the sum of individual measurements.Results: Significant differences were observed in the between-subgroup comparisons (Kruskal–Wallis test) of the MPI (3 months, p = 0.01; 6 months, p = 0.04) and linear deviation from intercuspal position (anterior–posterior: 6 months, p = 0.01; inferior–superior: 3 months, p = 0.008; 6 months, p = 0.02). The patients with severe RRR in the FBBA group showed a significant decrease in the MPI and increase in linear inferior deviation from intercuspal position at 3 months (post hoc comparison) as well as a significant increase in the linear posterior and inferior deviation from intercuspal position at 6 months.Conclusions: LO is the preferable occlusal scheme for patients with severe RRR. (This trial has been registered at http://clinicaltrials.gov/ct2/show/NCT00959530.)   

Marfan syndrome is an autosomal dominant disease characterized by aneurysm and dilatation of the aortic root, tall stature, and ectopia lentis. These manifestations reflect excessive signaling of transforming growth factor (TGF)-?. Moreover, patients are frequently associated with severe periodontitis which is a chronic inflammation of the gingiva, periodontal ligament and alveolar bone. Recently, angiotensin II receptor blockers (ARBs) were discovered as an effective drug that can prevent aortic aneurysm and dilation in Marfan syndrome by inhibiting TGF-? signaling. To investigate the effect of ARB on the progression of periodontitis, the application of a potent ARB, telmisartan, was examined in a mouse model of Marfan syndrome (Mg?). Six-week-old male heterozygous Mg? and wild-type mice were challenged with Porphyromonas gingivalis that causes chronic periodontitis, with and without telmisartan application. After infection, alveolar bone resorption was measured by micro-computed tomography (?CT), and inflammatory cytokine levels were examined. Infection of Porphyromonas gingivalis induced alveolar bone resorption in both Mg? and wild-type mice. The amount of resorption was significantly larger in the former than the latter. Immunoarray and ELISA demonstrated that interleukin (IL)-17 and tumor necrosis factor (TNF)-a levels were significantly higher in infected Mg? mice than infected wild-type mice. Telmisartan treatment significantly suppressed the alveolar bone resorption of infected Mg? mice. Telmisartan also significantly decreased levels of TGF-?, IL-17 and TNF-? in infected Mg? mice to levels seen in infected wild-type mice. This study suggests that ARB can prevent the severe periodontitis frequently seen in Marfan syndrome. PMID:23115041

Benign alveolar ridge keratosis is a common benign white papule or plaque that occurs on the keratinized gingiva of the maxillary or mandibular alveolar ridge that is probably traumatic/frictional in origin, with characteristic histologic features, similar to those of lichen simplex chronicus of the skin. This is a retrospective study of 108 consecutive specimens displaying characteristic histopathologic features of benign alveolar ridge keratosis accessioned during a 36-month period. There was a male:female ratio of 3.7:1. It occurred on the attached gingiva, with the retromolar area and the edentulous alveolar ridge involved in 51% and 49% of cases, respectively; 19% were bilateral and all bilateral cases were on the retromolar pad. Detailed clinical information was available on 27 cases...

Guided bone regeneration (GBR) in implant therapy is especially useful for implant placement with dehiscence defects or fenestration defects. In alveolar ridges with marked facial/buccal depressions or in knifeedge alveolar crests, the position and direction of fixture placement is restricted. Improvement of alveolar ridge morphology becomes possible with GBR. This article describes a case in which the fenestration defect around an implant was treated by the application of platelet rich fibrin, a second generation platelet concentrate along with bone graft, and guided tissue regeneration membrane. PMID:22628974

doi: 10.1111/j.1741-2358.2011.00610.x The effect of osteoporosis on residual ridge resorption and masticatory performance in denture wearers Aim:- To compare masticatory performance, masticatory efficiency and residual ridge resorption (RRR) in osteoporotic and non-osteoporotic edentulous subjects after rehabilitation with complete dentures. Method:- Thirty subjects fulfilling the inclusion criteria were enrolled from the patients visiting the Department of Prosthodontics for complete denture fabrication. Two groups consisting of control subjects (group I; N-=-15) and osteoporotic subjects (group II; N-=-15) were formed. Complete dentures satisfying certain criteria were fabricated for both groups. Masticatory performance and efficiency were measured 6-months after denture insertion. Areal...

Single-tooth alveolar osteotomy followed by distraction osteogenesis was applied to move an infrapositional ankylosed tooth to the normal position. A maxillary right canine of a 16-year-old female patient was at 6 mm infraposition compared with the maxillary left canine. Single-tooth alveolar osteotomy was performed under general anesthesia. After suturing the wound, an extrawound distraction device was attached to the crown of the ankylosed canine. The distance of movement was 7 mm. After the distraction movement, the fragment was fixed with wires and resin. The consolidation period was 2 months. During the treatment period, 2 complications associated with the roots occurred: injury of the root of the neighboring tooth during osteotomy and progressive inflammatory root resorption of the ankylosed tooth. The root fragments of the neighboring tooth fused spontaneously and the tooth did not show any symptoms of root resorption. The progressive inflammatory root resorption, which occurred at the cervical portion, was treated by removing the granulation in the resorption-lacuna and restoration with composite resin. It was suggested that root injury under sterile conditions probably promoted periodontal healing. Careful postoperative observation was necessary to detect and promptly treat the progressive inflammatory root resorption.   

OBJECTIVES: This investigation focused on long-term changes in graft height, implant survival rate, and peri-implant tissue conditions of dental implants placed in alveolar ridges after augmentation procedures with a follow-up of 10 years. MATERIAL AND METHODS: We conducted a retrospective cohort study with prospective long-term follow-up of 25 patients with edentulous severe atrophic maxillary situations who received a vertical augmentation procedure with autologous bone prior to implant placement. The participants were divided into three groups according to whether they underwent sinus elevation, onlay grafting, or a combination of both techniques. After a four-month healing period, 127 implants were inserted in the corresponding regions. Following a six-month healing period, the participants underwent prosthodontic rehabilitation, incorporating a fixed or removable implant denture. The cohort was clinically and radiographically followed up 1, 5, and 10 years after augmentation. The following parameters were measured: radiographic vertical bone changes, implant loss, peri-implant pocket depth (PD), width of keratinized mucosa (KM), sulcus fluid flow rate (SFFR), and the radiographic distance between the implant shoulder and the first visible bone-to-implant contact (DIB). RESULTS: Seven implants were lost during the observation period, resulting in a cumulative 10-year survival rate of 94.48%. Significant bone loss occurred during the first 12 months, after which the resorption slowed down and bone height eventually stabilized. After 10 years, the total vertical bone loss was 27.51% after onlay grafting, 28.14% after sinus elevation, and 30.24% in the combination group, with no statistically significant between-group differences. Peri-implant follow-up examinations revealed a positive correlation between SFFR and PD, respectively, DIB, and a negative correlation between SFFR and KM. CONCLUSION: The treatment method does not seem to impact vertical bone loss following augmentation using autologous grafts. This approach results in long-term stability of dental implants. A sufficient width of keratinized peri-implant mucosa is important to prevent peri-implant bone loss and inflammation. PMID:23075057

The aim of this study was to retrospectively evaluate the surgical technique of sinus floor elevation with autogenous parietal bone grafting in conjunction with immediate dental implants for the reconstruction of the maxilla in deficient maxillary alveolar ridges. Seventeen patients who underwent sinus floor elevation with bone graft from the parietal bone between 2005 and 2007 were included in the study. Cases of extremely deficient bone level in the alveolar ridgequality reconstruction with an increase in lifted sinus bone height was achieved with parietal bone particulates. Seventy-three implants were clinically osseointegrated and four implants were lost giving a success rate 94.8%. No correlation was found between failure and the surgery. The encouraging results of this study suggest that the technique of reconstruction of the sinus floor and the resorbed alveolar ridge using an autogenous parietal bone graft is reliable, giving the surgeon the opportunity to successfully perform immediate implant placement in more difficult and deficient maxillary alveolar bone height. PMID:20833553

The biological mechanisms that maintain the position of teeth in their sockets establish a dynamic equilibrium between bone resorption and apposition. In order to reveal some of the dynamics involved in the tissue responses towards occlusal forces on periodontal ligament (PDL) and alveolar bone homeostasis, we developed the first mouse model of hyperocclusion. Swiss-Webster mice were kept in hyperocclusion for 0, 3, 6, and 9 d. Morphological and histological changes in the periodontium were assessed using micro-computed tomography (micro-CT) and ground sections with fluorescent detection of vital dye labels. Sections were stained for tartrate-resistant acid phosphatase, and the expression of receptor activator of nuclear factor-{kappa}B ligand (RANKL) and osteopontin (OPN) was analyzed by immunohistochemistry and real-time polymerase chain reaction (PCR). Traumatic occlusion resulted in enamel surface abrasion, inhibition of alveolar bone apposition, significant formation of osteoclasts at 3, 6 and 9 d, and upregulation of OPN and RANKL. Data from this study suggest that both OPN and RANKL contribute to the stimulation of bone resorption in the hyperocclusive state. In addition, we propose that the inhibition of alveolar bone apposition by occlusal forces is an important mechanism for the control of occlusal height that might work in synergy with RANKL-induced bone resorption to maintain normal occlusion.

A better understanding of the remodeling process of postextraction sockets is essential in dental treatment planning. The aim of this study was to evaluate whether confocal laser scanning microscopy (CLSM) can be applied to imaging contour changes of postextraction sites, as well as to its quantification with image analysis of obtained three-dimensional images. This work describes a new application of the CLSM technique. The system used was the OLS3100-USS, LEXT model (Olympus®). CLSM was used for the surface analysis of the extraction site. The measurements taken with CLSM were: (1) mesio-distal distance, (2) alveolar ridge thickness, and (3) vestibular and lingual alveolar ridge height. Results of study cast scanning at baseline, 1 and 3 months after tooth extraction, with CLSM are well-detailed images of postextraction areas. The CLSM technique used in study casts is a valid method to measure the dimensional changes that happen in the edentulous area after tooth extraction. This technique allows the evaluation of changes in mesio-distal distance, thickness of the alveolar ridge and alveolar ridge height based on the measurements on the alveolar contours. PMID:22553827

We examined effects of local and whole body irradiation before tooth extraction on appearance and differentiation of osteoclasts in the alveolar bone of rat maxillary first molars. Wistar rats weighting 100 g were divided into three groups: non-irradiation group, local irradiation group, and whole body irradiation group. In the local irradiation group, a field made with lead blocks was placed over the maxillary left first molar tooth. In the whole body irradiation group, the animals were irradiated in cages. Both groups were irradiated at 8 Gy. The number of osteoclasts around the interradicular alveolar bone showed chronological changes common to non-irradiated and irradiated animals. Several osteoclasts appeared one day after tooth extraction, and the maximal peak was observed 3 days after extraction. Local irradiation had no difference from non-irradiated controls. In animals receiving whole body irradiation, tooth extraction one day after irradiation caused smaller number of osteoclasts than that 7 day after irradiation during the experimental period. Whole body-irradiated rats had small osteoclasts with only a few nuclei and narrow resorption lacunae, indicating deficiency of redioresistant osteoclast precursor cells. Injection of intact bone marrow cells to whole body-irradiated animals immediately after tooth extraction recovered to some content the number of osteoclasts. These findings suggest that bone resorption in the wound healing of alveolar socket requires radioresistant, postmitotic osteoclast precursor cells from hematopoietic organs, but not from local sources around the alveolar socket, at the initial phase of wound healing.   

The differentiation and functions of osteoclasts (OC) are regulated by osteoblast-derived factors such as receptor activator of NFKB ligand (RANKL) that stimulates OC formation, and a novel secreted member of the TNF receptor superfamily, osteoprotegerin (OPG), that negatively regulates osteoclastogenesis. In examination of the preosteoclast (pOC) culture, pOCs formed without any additives expressed tartrate-resistant acid phosphatase (TRAP), but showed little resorptive activity. pOC treated with RANKL became TRAP-positive OC, which expressed intense vacuolar-type H(+)-ATPase and exhibited prominent resorptive activity. Such effects of RANKL on pOC were completely inhibited by addition of OPG. OPG inhibited ruffled border formation in mature OC and reduced their resorptive activity, and also induced apoptosis of some OC. Although OPG administration significantly reduced trabecular bone loss in the femurs of ovariectomized (OVX) mice, the number of TRAP-positive OC in OPG-administered OVX mice was not significantly decreased. Rather, OPG administration caused the disappearance of ruffled borders and decreased H(+)-ATPase expression in most OC. OPG deficiency causes severe osteoporosis. We also examined RANKL localization and OC induction in periodontal ligament (PDL) during experimental movement of incisors in OPG-deficient mice. Compared to wild-type OPG (+/+) littermates, after force application, TRAP-positive OC were markedly increased in the PDL and alveolar bone was severely destroyed in OPG-deficient mice. In both wild-type and OPG-deficient mice, RANKL expression in osteoblasts and fibroblasts became stronger by force application. These in vitro and in vivo studies suggest that RANKL and OPG are important regulators of not only the terminal differentiation of OC but also their resorptive function. To determine resorptive functions of OC, we further examined the effects of specific inhibitors of H(+)-ATPase, bafilomycin A1, and lysosomal cysteine proteinases (cathepsins), E-64, on the ultrastructure, expression of these enzymes and resorptive functions of cultured OC. In bafilomycin A1-treated cultures, OC lacked ruffled borders, and H(+)-ATPase expression and resorptive activity were significantly diminished. E-64 treatment did not affect the ultrastructure and the expression of enzyme molecules in OC, but significantly reduced resorption lacuna formation, by inhibition of cathepsin activity. Lastly, we examined the expression of H(+)-ATPase, cathepsin K, and matrix metalloproteinase-9 in odontoclasts (OdC) during physiological root resorption in human deciduous teeth, and found that there were no differences in the expression of these molecules between OC and OdC. RANKL was also detected in stromal cells located on resorbing dentine surfaces. This suggests that there is a common mechanism in cellular resorption of mineralized tissues such as bone and teeth. PMID:12879416

This publication describes the clinical case of a 75-year-old woman. She suffered from total alveolar ridge atrophy due to 20 years of wearing dentures. Bone transplantation, including harvesting of the iliac crest, was rejected by another clinic due to various existing diseases and risk of blood loss on donor side. Moreover, the minimal residual alveolar ridge did not allow bone fixation using screws nor did it allow osteodistraction. Before deciding which bone tissue engineering techniques should best be employed in this surgical treatment, cardiological and internistic consultations and treatments were carried out. In addition, anesthetic preparations were made. The surgical treatment was performed implementing special bridge flap techniques to preserve the periosteum. Tricalcium phosphate blocks soaked with recombinant human bone morphogenetic protein-2 and platelet-rich plasma were implanted on the narrow alveolar ridge. They were attached by tightening the soft tissue, including the periosteum. Four months later, after complication-free wound healing and bone regeneration, six dental implants were inserted into the new alveolar ridge. The histology of all bone samples showed vital lamellar bone. Three months after implantation, a new dental structure was fixed on the implants. The patient's quality of life improved significantly with this new situation. PMID:20302447

The restoration and recovery of the alveolar healing process are a challenge to dental surgeons to achieve satisfactory results at the osseointegration of implants and implant rehabilitation. Different operative technique and biomaterials are being used to reconstruct the framework of the alveolar process. One of the biomaterials used for this purpose is the bioactive glass. The aim of this study was to report clinical and histologic final results of 7 clinical reports of alveolar ridge augmentation using bioactive glass. Clinically, bioglass was able to maintain bone architecture of the alveolar bone and repaired satisfactory. Biopsy was performed on the histologic samples and showed bone formation in intimate contact to the particles of the biomaterial. PMID:22627439

Human recombinant bone morphogenetic protein 2 (rhBMP-2) accelerates bone regeneration but is associated with limited cementum and periodontal ligament regeneration, local root resorption, and ankylosis. This study assessed a new approach to the regeneration of the alveolar bone and periodontal attachment apparatus using a combination of ex vivo autologous bone marrow mesenchymal stem cells (MSCs) engineered by replication defective adenovirus to express the BMP-2 gene and pluronic F127 (PF127) in a large mammalian animal model. Bilateral maxillary periodontal defects were created over the premolar area in 9 mature male miniature swine. The 18 defects were randomly assigned to receive either BMP-2-expressing MSCs in the advBMP-2 group or MSCs alone in the MSC group. The regenerated periodontal attachment apparatus was evaluated histologically, and the total regenerated bone volume was calculated from three-dimensional computed tomography analysis. Three months after implantation, significant bone volume was regenerated in the advBMP-2 group. Periodontal apparatus regeneration was significantly better in the advBMP-2 group. New cementum and Sharpey fibers were observed on the denuded root surfaces in the advBMP-2 group, whereas incomplete healing with localized root surface resorption was noted in the control group. The use of ex vivo BMP-2-engineered autologous MSCs enhanced bone and periodontal apparatus regeneration in maxillary alveolar and periodontal defects in swine. This novel integrated approach might be suitable for clinical periodontal apparatus repair. This may be an alternative for cleft alveolar bone graft surgery. PMID:22976660

doi: 10.1111/j.1741-2358.2010.00440.x Loss of natural dentition: multi-level effects among a geriatric population Objective:- To quantify the impact of edentulousness on residual ridge volume, denture stomatitis (DS), as well as oral health behaviours among geriatric denture-wearers. Background:- Residual ridge resorption (RRR) is the primary intraoral complication of complete edentulism, but individual variation among geriatric patients has been observed. Materials and methods:- Data collection relied upon a 10-year retrospective chart review of all complete denture-wearing geriatric patients presenting at the Removable Prosthodontics Clinic, Dental School of Athens, between 1993 and 2002. Analyses relied on descriptive, bivariate, and multivariate methods based on ordinal logistic regres...

The aim of this study was to quantify the frequency of positive radiographic findings in edentulous arches. Panoramic radiographs from 271 patients who were edentulous in one or both arches were evaluated for the presence of retained root fragments, impacted teeth, foreign bodies, radiolucencies, radiopacities, mental foramina at or near the crest of the residual alveolar ridge, and maxillary sinus proximity to the crest of the residual alveolar ridge. One or more of these radiographic observations were found in 51.7% of the examined films. The most frequent finding (30.6%) was close approximation of the maxillary sinus to the crest of the ridge. These results underscore the importance of panoramic examination of edentulous patients in detecting potential problems before complete denture treatment. However, prescribing such an examination in patients seeking replacement dentures requires a thorough patient history and clinical examination. PMID:21210005

Abstract in english Matrix metalloproteinases (MMP) are considered to be key initiators of collagen degradation, thus contributing to bone resorption in inflammatory diseases. We determined whether subantimicrobial doses of doxycycline (DX) ((more) 7 days. Alveolar bone loss (ABL) was measured macroscopically in one hemiarcade and the contralateral hemiarcade was processed for histopathologic analysis. Groups of six animals each were treated with DX (2.5, 5 or 10 mg kg-1 day-1, sc, 7 days) and compared to nontreated (NT) rats. NT rats displayed significant ABL, severe mononuclear cell influx and increase in osteoclast numbers, which were significantly reduced by 5 or 10 mg kg-1 day-1 DX. These data show that DX inhibits inflammatory bone resorption in a manner that is independent of its antimicrobial properties.

Summary Treponema denticola is associated with subgingival biofilms in adult periodontitis and with acute necrotizing ulcerative gingivitis. However, the molecular mechanisms by which T. denticola impacts periodontal inflammation and alveolar bone resorption remain unclear. Here, we examined changes in the host transcriptional profiles during a T. denticola infection using a murine calvarial model of inflammation and bone resorption. T. denticola was injected into the subcutaneous soft tissue over the calvaria of BALB/c mice for 3 days, after which the soft tissues and the calvarial bones were excised. RNA was isolated and analysed for transcript profiling using Murine GeneChip arrays. Following T. denticola infection, 2905 and 1234 genes in the infected calvarial bones and soft tissues, r...

During orthodontic tooth movement (OTM), alveolar bone is resorbed by osteoclasts in compression sites (CS) and is deposited by osteoblasts in tension sites (TS). The aim of this study was to develop a standardized OTM protocol in mice and to investigate the expression of bone resorption and deposition markers in CS and TS. An orthodontic appliance was placed in C57BL6/J mice. To define the ideal orthodontic force, the molars of the mice were subjected to forces of 0.1N, 0.25N, 0.35N and 0.5N. The expression of mediators that are involved in bone remodeling at CS and TS was analyzed using a Real-Time PCR. The data revealed that a force of 0.35N promoted optimal OTM and osteoclast recruitment without root resorption. The levels of TNF-?, RANKL, MMP13 and OPG were all altered in CS a...

Background: Extensive alveolar bone resorption in the maxilla limits the possibility of successful placement and osseointegration of endosseous implants for future prosthetic rehabilitation. Autogenous bone from the iliac crest may be used as lateral onlays in the atrophic maxilla, both as block and particulate bone. To our knowledge, there is no three-dimensional 2-year follow-up study measuring the volumetric reduction of the augmented areas comparing particulate and block bone grafts. Purpose: The aim of this study was to conduct a radiographic 2-year follow-up study, using computed tomographic (CT) images in order to evaluate and compare the extent of bone graft resorption in the frontal maxillae augmented by particulate (test) and block bone (control). Material and methods: Eleven pat...

Periodontal disease (PD) is characterized by the inflammatory bone resorption in response to the bacterial challenge, in a host response that involves a series of chemokines supposed to control cell influx into periodontal tissues and determine disease outcome. In this study, we investigated the role of chemokines and its receptors in the immunoregulation of experimental PD in mice. Aggregatibacter actinomycetemcomitans-infected C57Bl/6 (WT) mice developed an intense inflammatory reaction and severe alveolar bone resorption, associated with a high expression of CCL3 and the migration of CCR5+, CCR1+ and RANKL+ cells to periodontal tissues. However, CCL3KO-infected mice developed a similar disease phenotype than WT strain, characterized by the similar expression of cytokines (TNF-a, IFN-g a...

AIM: To evaluate the influence of the presence or absence of adjacent teeth on the level of the mesial and distal alveolar bony crest following healing at sites where implants were installed immediately into extraction sockets. MATERIAL AND METHODS: Six Labrador dogs were used. In the right side of the mandible, full-thickness flaps were elevated, and the second, third, and fourth premolars and first molars were extracted. In the left side of the mandible, endodontic treatments of the mesial roots of the third and fourth premolars as well as of the first molars were performed. Full-thickness flaps were elevated, the teeth were hemi-sected, and the distal roots were removed. The second premolars were extracted as well. Subsequently, implants were bilaterally installed with the implant shoulder flush with the buccal bony crest. Implants were placed in the center of the alveoli, but at the fourth premolars, they were placed toward the lingual bony plate of the alveoli. After 3 months of healing, the animals were euthanized and histological sections of the sites prepared. RESULTS: Larger bony crest resorption was observed at the test compared with the control sites, both at the bucco-lingual and mesio-distal aspects. The differences between test and controls for the coronal level of osseointegration were smaller than those for resorption. When data from all mesial and distal sites facing an adjacent tooth were collapsed and compared with those opposing an edentulous zone, lower bony crest resorption and deeper residual marginal defects were found at the sites with neighboring teeth. CONCLUSION: The extraction of teeth adjacent to a socket into which implants were installed immediately after tooth extraction caused more alveolar bone resorption both for the bucco-lingual and at the mesio-distal aspects compared with sites adjacent to a maintained tooth. PMID:22909080

Dental implants are established alternatives for replacing missing teeth. Tooth loss for different reasons may leads to alveolar resorption. Shortage of bone can prevent proper positioning of dental implants according to prosthetic needs and treatment planning, unless the volume of hard and soft tissues is increased before implantation. In the esthetic area it is essential not only to achieve well-anchored implants but also sufficient soft and hard tissue in order to obtain natural looking result. This article will present several treatment modalities to augment the soft and hard tissues in order to obtain proper insertion of implants according to prosthetic needs and patient satisfaction.   

Kim M, Jun H K, Choi B K, Cha J H, Yoo Y J. Td92, an outer membrane protein of Treponema denticola, induces osteoclastogenesis via prostaglandin E2 mediated RANKL/osteoprotegerin regulation. J Periodont Res 2010; 45: 772 779. 2010 John Wiley & Sons A/S Background and Objective: Periodontitis is a chronic inflammatory disease of the periodontium that causes significant alveolar bone loss. Osteoclasts are bone resorbing multinucleated cells. Osteoblasts regulate osteoclast differentiation by expression of RANKL and osteoprotegerin (OPG). Td92 is a surface exposed outer membrane protein of Treponema denticola, a periodontopathogen. Although it has been demonstrated that Td92 acts as a stimulator of various proinflammatory mediators, the role of Td92 in alveolar bone resorption remains unclear...

The present study examined the influence of different post materials and their lengths on the mechanical stress of endodontically treated incisor roots in two alveolar bone conditions. Two-dimensional photoelastic models were fabricated to simulate the endodontically treated maxillary central incisors restored with three kinds of posts materials (low Young's modulus glass fiber post, high Young's modulus glass fiber post, and prefabricated stainless steel post) and two post lengths (8 and 4 mm). Completed models were placed in a transmission polariscope and loaded with a static force of 150 N at 45° to the tooth axis. Photoelastic photographs and the magnitudes of fringe order revealed stress distribution in the root, and suggest that the glass fiber post with a low Young's modulus and long length can reduce the stress concentration both in normal and alveolar bone resorption conditions. PMID:22123004

Statement of problem In edentulous patients, alveolar bone loss is a critical factor that affects denture retention, stability, and masticatory function. In addition to their use for the assessment of bone quality, panoramic radiomorphometric indices have been used to observe signs of bone resorption. Currently, there is no published data on the possible relationships between bone loss, radiomorphometric indices, and edentulism. Purpose The purpose of this study was to investigate the influence of age and gender on the mandibular cortical index, panoramic mandibular index, and mandibular cortical width, as well as alveolar bone loss and bone height, using panoramic radiographs of patients having been edentulous for more than 2 years. Material and methods Panoramic radiographs of 94 edentul...

Following tooth extraction, the alveolar ridge undergoes an inevitable remodeling process that influences implant therapy of the edentulous area. Socket grafting is a commonly adopted therapy for the preservation of alveolar bone structures in combination or not with immediate implant placement although the biological bases lying behind this treatment modality are not fully understood and often misinterpreted. This review is intended to clarify the literature support to socket grafting in order to provide practitioners with valid tools to make a conscious decision of when and why to recommend this therapy. PMID:17260521

A semiautomated, radiograph-based classifier of alveolar bone quality for dry skulls was developed. Bone quality was based on the assessment of surface features, such as the resorption of cortical bone and the presence of vertical defects. The consensus of two trained observers was used to rate 50 mandibular quadrants of 29 skulls as having normal or poor alveolar bone quality. Bitewing radiographs were taken of the mandibles and digitized with a 35 mm, solid-state slide scanner at 1024 X 1520 X 8 bits. Regions of interest (ROI) of alveolar bone between the mandibular first and second molars were chosen. For these ROIs, gray-scale values were plotted as histograms. Nonzero portions of the histogram were mapped to a 100-cell scale and cumulative percentage frequency curves of these were calculated. Average cumulative frequency distributions were calculated for 14 cases with normal bone quality and 11 cases with poor bone quality. These distributions were used to develop an automatic classifier based on differences between the cumulative frequency curve for each case and the average cumulative frequency curves for normal and poor quality bone. The bone quality of 43 of the 50 quadrants was successfully determined with this classifier. Of the seven misses, two were from one skull with severely tilted teeth; three were associated with bleached museum specimens; and the remaining two appeared to be a failure of the classifier. These preliminary results are encouraging. This classifier will be applied to a longitudinal series of bitewings of patients to predict alveolar bone loss.

Purpose: The aim of this study was to determine the importance of each morphological factor of edentulous alveolar ridges according to its influence on the movement of complete dentures.Methods: The shapes of casts and waxed complete dentures were digitized. The determined shapes of the ridges were uniformly divided circumferentially and radially. Principal component (PC) analysis was performed using the coordinates of the points on the grid as the variables (morphological PC). The denture movement under bilateral and unilateral loads was analyzed using a finite element (FE) model constructed from the digitized shape, following PC analysis of the displacement of representative points on the denture (displacement PC). The effects of the morphological PCs were evaluated by means of stepwise multiple regression analysis with displacement PC as a dependent variable.Results: The ridge height, clearance between the ridge and the occlusal plane, and various inclinations, were significantly selected as independent variables where the dependent variable was the displacement PC under a bilateral load. Under a unilateral load, the displacement PC was mainly influenced by the ridge height. The influence of morphological PCs of the non-loaded side tended to be larger than that of loaded side.Conclusion: Under a bilateral load, ridge height, clearance to the occlusal plane, and inclination of the ridge are considered to account for denture movement. To evaluate the effect of the ridge morphology on denture movement under a unilateral load, it is effective to determine the partitioned shape together with the height in general.   

The prevalence of obesity is increasing globally. There is evidence that the uncontrolled energetic metabolism in obese patients can accelerate periodontal disease. Therefore, the aim of this study was evaluate the possible relationship between hypothalamic obesity induced by neonatal treatment with MSG and experimental periodontal disease. Newborn male Wistar rats received subcutaneous injections in the cervical region, of 4g/Kg/day of body weight (BW) of MSG (MSG group) or hypertonic saline solution, 1.25/kg/day BW (control group, CTL). At 70 days of life periodontal disease was induced in these animals. After they were sacrificed, radiographic analyses of alveolar bone resorption and Tumor Necrosis Factor ? (TNF?) gene expression in gingival tissue were performed. The neonatal treatment with MSG did not affect the concentration of plasma glucose and cholesterol (CHOL). However, plasma insulin, non-esterified fatty acids (NEFA) and triglycerides (TG) leves were higher in MSG compared with CTL group. The alveolar bone resorption was 44% lower in MSG-obese rats compared with CTL rats. In the presence of periodontal ligature, there was an increase in this parameter in all groups. The TNF? gene expression, an inflammatory marker, in periodontal tissue was similar in obese and CTL rats. The presence of ligature increased TNF? gene expression in both groups, but in a lower extension in MSG-obese rats. In conclusion these results suggested that hypothalamic obesity may produce a protective effect against periodontal disease, however further research is needed to understand the mechanisms involved in this process. PMID:22129469

Abstract Introduction: Tooth extraction is followed by marked osseous changes of the residual alveolar ridge including severe bone alterations both in height and in width. However, such remodelling could jeopardize the subsequent implant insertion for two main reasons. Firstly, the absence of adequate bone levels makes implant placement impossible; secondly, aesthetic problems in the fabrication of implanto-supported restoration could be caused by serious bone re-absorption. Thus, it is of crucial importance that the dental surgeon knows how the alveolar crest changes when a single tooth has been removed. The aim of this study was to evaluate the pattern of alveolar crest remodelling observed in a single intercalated area of tooth extraction after at least a period of 6 months of healing, ...

Van der Weijden F, Dell'Acqua F, Slot DE. Alveolar bone dimensional changes of post-extraction sockets in humans :a systematic review. J Clin Periodontol 2009; 36: 1048-1058. doi: 10.1111/j.1600-051X.2009.01482.x. Abstract Objective: To review the literature to assess the amount of change in height and width of the residual ridge after tooth extraction. Material and Methods: MEDLINE-PubMed and the Cochrane Central register of controlled trials (CENTRAL) were searched through up to March 2009. Appropriate studies which data reported concerning the dimensional changes in alveolar height and width after tooth extraction were included. Approximal height change, mid-buccal change, mid-crestal change, mid-lingual change, Alveolar width change and socket fill were selected as outcome variables. M...

Abstract A better understanding of the remodeling process of postextraction sockets is essential in dental treatment planning. The aim of this study was to evaluate whether confocal laser scanning microscopy (CLSM) can be applied to imaging contour changes of postextraction sites, as well as to its quantification with image analysis of obtained three-dimensional images. This work describes a new application of the CLSM technique. The system used was the OLS3100-USS, LEXT model (Olympus). CLSM was used for the surface analysis of the extraction site. The measurements taken with CLSM were: (1) mesio-distal distance, (2) alveolar ridge thickness, and (3) vestibular and lingual alveolar ridge height. Results of study cast scanning at baseline, 1 and 3 months after tooth extraction, with CLSM a...

Polimeni G, Wikesjo UME, Susin C, Qahash M, Shanaman RH, Prasad HS, Rohrer MD, Hall J. Alveolar ridge augmentation using implants coated with recombinant human growth/differentiation factor-5: histologic observations. J Clin Periodontol 2010; 37: 759-768 doi: />. Abstract Objectives: In vitro and in vivo preclinical studies suggest that growth/differentiation factor-5 (GDF-5) may induce local bone formation. The objective of this study was to evaluate the potential of recombinant human GDF-5 (rhGDF-5) coated onto an oral implant with a purpose-designed titanium porous oxide surface to stimulate local bone formation including osseointegration and vertical augmentation of the alveolar ridge. Materials and Methods: Bilateral, critical-size, 5 mm, supraalveolar peri-implant defects were create...

'Dentures: A question of grinning and bearing it' is not just the title of a 25-year-old thesis, but it also reflects the content well. Dissatisfaction with complete dentures is not only determined by the quality of the dentures and the oral conditions, but also and just as much by the patient's capacity to adapt to and accept the dentures. In order to treat an edentulous patient adequately, an oral healthcare provider should pay special attention to these aspects. After 25 years of further scientific study, this conclusion is still true. The current care standard for edentulous patients with atrophy of the residual mandibular alveolar ridge is an overdenture supported by 2 implants. For edentulous patients with a solid residual mandibular alveolar ridge, conventional complete dentures are the first choice of treatment. Only in cases of obvious remaining complaints, should an implant-supported overdenture be considered. PMID:21661249

This publication describes the clinical case of a 75-year-old woman. She suffered from total alveolar ridge atrophy due to 20 years of wearing dentures. Bone transplantation, including harvesting of the iliac crest, was rejected by another clinic due to various existing diseases and risk of blood loss on donor side. Moreover, the minimal residual alveolar ridge did not allow bone fixation using screws nor did it allow osteodistraction. Before deciding which bone tissue engineering techniques should best be employed in this surgical treatment, cardiological and internistic consultations and treatments were carried out. In addition, anesthetic preparations were made. The surgical treatment was performed implementing special bridge flap techniques to preserve the periosteum. Tricalcium phosph...

Oral carcinomas are frequently treated with a nonsegmental mandibulectomy plus radiotherapy. Improving the quality of life of these patients depends on the possibilities for dental rehabilitation. The aim of this study was to increase the alveolar ridge height. Twelve white New Zealand rabbits underwent surgery to produce a 11 x 9 x 7 mm3 horizontal bicortical full-thickness defect at the alveolar ridge of the left mandible. Six were implanted with a composite associating resorbable collagen membrane filled with micro-macroporous biphasic calcium phosphate granules. After a daily radiation delivery schedule for 4 weeks, a total autologous bone marrow graft was injected percutaneously into the center of the implant. All animals were sacrificed at 16 weeks. Successful osseous colonization wa...

Oral Diseases (2010) 17, 33 44 Objectives: To study the natural aetiopathology of jaw atrophy after tooth loss, unaltered by prosthetic procedures, an historical population without modern dental treatment was examined. Methods: Based on the hypothesis that there are predictable changes in shape during jaw atrophy, frequency and degree of atrophy as well as clinical aspects of bone quality and resorption were determined in the skeletal remains of 263 individuals. The potential association between age and frequency/severity of atrophy was analysed. Results: Atrophy in at least one jaw segment was present in 45.2% of the analysed jaw specimens. The residual ridge underwent a series of changes in shape and height following the pattern of resorption described for modern populations. The severit...

Abstract in spanish Este estudio tiene como objetivo evaluar clínica y radiográficamente la técnica de distracción osteogénica alveolar en la región anterior del maxilar superior y las posibles complicaciones que pueden aparecer durante el tratamiento. Fueron evaluados 15 pacientes, sometidos a reconstrucción alveolar del maxilar superior en la región anterior con distracción osteogénica, usando un distractor yuxtaóseo. Del total de 15 pacientes encontramos que 13 pacientes (86,6% (more) ) obtuvieron un éxito total de la técnica, obteniendo una ganancia ósea real media de 7,04 mm; en 1 paciente (6,66%) fue parcial (2,62 mm) y en 1 paciente (6,66%) se evidenció un fracaso en la técnica, al alcanzar solo 0,76 mm debido a problemas en la activación del distractor. En cuanto a las complicaciones surgidas durante el tratamiento fueron divididas en complicaciones menores, toda aquella que no interfirió en el éxito del tratamiento, y que estuvieron presentes en 8 pacientes (53,33%), y complicaciones mayores aquellas que no permitieron la rehabilitación con implantes, y que fue encontrado solo en 1 paciente (6,66%). La técnica de distracción osteogénica alveolar, demostró ser eficaz en la reconstrucción de rebordes alveolares atróficos con un éxito de 93,33%, presentado pequeñas complicaciones que pueden ser solventadas por medio de un seguimiento por parte del profesional. Abstract in english This study evaluates clinically and radiographically the distraction osteogenesis technique for the reconstruction of atrophic alveolar ridges in the anterior maxilla region, and the possible complications that arise during treatment. Fifteen patients were evaluated, clinically and radiographically, that had been treated with alveolar distraction osteogenesis in the anterior region, using a juxta-osseous distractor. In 13 patients (86.6%) the technique was completely succ (more) essful, there being an effective bone gain of 7,04 mm. In 1 patient (6.66%) this was partial (2.62 mm) and in 1 patient (6.66%) the technique failed, as there was a gain of just 0,76 mm because of problems during the activation. The complications arising during the alveolar distraction osteogenesis were divided into minor complications that did not compromise the success of the technique, and which were found in 8 patients (53.33%), and major complications that did not permit rehabilitation, which were found in 1 patient (6.66%). The alveolar distraction osteogenesis technique proved to be an effective technique for the reconstruction of atrophic alveolar ridges with a success rate of 93.33%. There were minor complications but the surgeon intervened in time and these were solved.

Abstract in portuguese Várias técnicas e materiais têm sido sugeridos para a preservação do rebordo alveolar (PRA) após a extração dentária e antes da colocação do implante. Esta revisão de literatura buscou discutir os aspectos histológicos e clínicos da cicatrização do alvéolo e do procedimento PRA após a extração dentária e verificar se ele permite a colocação de implante dentário (com ou sem enxerto adicional). Apesar da heterogeneidade dos estudos, há evidência qu (more) e os procedimentos de preservação do rebordo são eficazes na limitação da perda dimensional do rebordo pós-extração e são acompanhados por um grau diferente de regeneração óssea, com variadas quantidades de partículas residuais dos "materiais de enxerto". Abstract in english Several techniques and materials have been suggested for alveolar ridge preservation (ARP) after dental extraction and before implant placement. This literature review aimed to discuss the histological and clinical aspects of alveolar healing and the ARP procedure after dental extraction and to verify whether it allows dental implant placement (with or without further augmentation). Despite the heterogeneity of the studies, some evidence suggests that ridge preservation p (more) rocedures are efficient in limiting the postextraction dimensional loss of the ridge and are accompanied by a different degree of bone regeneration, with varied amounts of residual graft material particles.

Bone remodeling, the selective deposition and resorption of bone, is an important cause of tooth eruption. During tooth eruption, reduced enamel epithelia of the enamel organ interact with follicle cells to recruit osteoclasts for bone remodeling. However, little is known about the relationship between cellular activity of reduced enamel epithelium and bone resorption during tooth eruption. The purpose of this study was to investigate the effect of apoptosis in reduced enamel epithelium on osteoclastogenesis and its implications for bone resorption. We have analyzed erupting mandibular molars in mice by TdT-mediated dUTP-biotin nick end labeling assay, tartrate-resistant acid phosphatase (TRAP) staining, and immunohistochemistry. TRAP-positive cells were detected in the osteoclasts near both the buccal and lingual sides of tooth socket at postnatal day 0 (PN0). They significantly increased until PN3 and decreased thereafter as the tooth erupted. Interestingly, apoptosis was barely detected in the reduced enamel epithelium at PN3 but clearly at PN7. A few apoptotic cells were also investigated within the dental follicle surrounding developing tooth at PN7 and PN10. We observed apoptotic osteoblast-lineage cells along the inner margin of alveolar bone facing the buccal cusp and at the base of the bony crypt at PN3 decreasing until PN10. In contrast, expression levels of bone sialoprotein increased at PN10 compared to levels at PN3. These results suggest that apoptosis of reduced enamel epithelium resulted in a reduction of osteoclast activity and of bone resorption mediated by dental follicle during tooth eruption. PMID:23124894

The resorption of alveolar bone in periodontitis and/or following tooth extraction results in a significant problem in an individual’s oral health-related quality of life. Strategies employing growth factor proteins and/or stem cell-based therapy have been successfully used to regenerate alveolar bone augmentation/regeneration; however, cost-effectiveness issues illustrate the need for developing alternative strategies. One promising approach is the development of conventional chemical and biological therapeutics to strongly stimulate endogenous cells to regenerate. Small-molecule compounds can have a variety of biological functions, serving as cell signaling molecules, as tools in molecular biology, and as drugs in medicine. Therefore, the discovery of natural and novel small-molecule synthetic regulators of differentiation and maturation of osteoblasts and/or osteoclasts would accelerate the development of bone regenerative medicine. Recently, “chemical biology” has started to play an increasingly important role in both drug discovery and elucidating the mechanism of biological phenomena. This review first addresses the current needs and strategies for alveolar bone regeneration, followed by the potential small molecules associated with bone regeneration, with a concluding section on chemical biology-based high throughput screening approaches for identifying small molecules targeting osteoblast/osteoclast differentiation.   

Periodontal disease (PD) is characterized by the inflammatory bone resorption in response to the bacterial challenge, in a host response that involves a series of chemokines supposed to control cell influx into periodontal tissues and determine disease outcome. In this study, we investigated the role of chemokines and its receptors in the immunoregulation of experimental PD in mice. Aggregatibacter actinomycetemcomitans-infected C57Bl/6 (WT) mice developed an intense inflammatory reaction and severe alveolar bone resorption, associated with a high expression of CCL3 and the migration of CCR5+, CCR1+ and RANKL+ cells to periodontal tissues. However, CCL3KO-infected mice developed a similar disease phenotype than WT strain, characterized by the similar expression of cytokines (TNF-alpha, IFN-gamma and IL-10), osteoclastogenic factors (RANKL and OPG) and MMPs (MMP-1, MMP-2, MMP-3, TIMP-1 and TIMP-3), and similar patterns of CCR1+, CCR5+ and RANKL+ cell migration. The apparent lack of function for CCL3 is possible due the relative redundancy of chemokine system, since chemokines such as CCL4 and CCL5, which share the receptors CCR1 and CCR5 with CCL3, present a similar kinetics of expression than CCL3. Accordingly, CCL4 and CCL5 kinetics of expression after experimental periodontal infection remain unaltered regardless the presence/absence of CCL3. Conversely, the individual absence of CCR1 and CCR5 resulted in a decrease of leukocyte infiltration and alveolar bone loss. When CCR1 and CCR5 were simultaneously inhibited by met-RANTES treatment a significantly more effective attenuation of periodontitis progression was verified, associated with lower values of bone loss and decreased counts of leukocytes in periodontal tissues. Our results suggest that the absence of CCL3 does not affect the development of experimental PD in mice, probably due to the presence of homologous chemokines CCL4 and CCL5 that overcome the absence of this chemokine. In addition, our data demonstrate that the absence of chemokine receptors CCR1+ and CCR5+ attenuate of inflammatory bone resorption. Finally, our data shows data the simultaneous blockade of CCR1 and CCR5 with MetRANTEs presents a more pronounced effect in the arrest of disease progression, demonstrating the cooperative role of such receptors in the inflammatory bone resorption process throughout experimental PD. PMID:20053385

Scientific literature describes autogenous bone as the gold standard among graft materials for alveolar reconstructive procedures. Alveolar ridge augmentation has been clinically achieved with different forms of autogenous bone, including autogenous cortical bone particulate (ACBP). However, few histologic studies demonstrating the biologic potential and healing dynamics following the use of ACBP are currently available. This case report presents 2 patients in whom atrophic edentulous alveolar crests were submitted to a vertical/lateral ridge augmentation prior to implant placement. The technique was performed through the use of a titanium-reinforced expanded polytetrafluoroethylene (e-PTFE) membrane with an ACBP graft obtained from the retromolar region with a specially designed bone scraper. Bone biopsy specimens were harvested at 9 months after graft placement. Analysis of the reconstructed bone revealed bone with a lamellar quality characterized by a mature osteonic structure. Sparse particles of grafted bone were evident in direct contact with the regenerated bone. Marrow spaces showed a normal stromal component with limited grafted particles. PMID:18416419

Summary Soft denture liners are applied for denture wearers who cannot tolerate a hard-based denture due to a thin and non-resilient oral mucosa and/or severe alveolar resorption. This material distributes and absorbs masticatory forces by means of the cushioning effect. Clinical success of the materials depends both on their viscoelastic properties and on durability. Acrylic resins and silicones are mainly available for permanent soft liners. The acrylic permanent soft liners demonstrate viscoelastic behavior while silicone permanent soft liners demonstrate elastic behavior. The improvement in masticatory function is greater in dentures lined with the acrylic materials than in those lined with silicone products. However, the acrylic materials exhibit a more marked change in viscoelastic p...

Abstract Background: After implant insertion and loading, crestal bone usually undergoes remodeling and resorption. If the horizontal relationship between the outer edge of the implant and a smaller-diameter component (`platform switching') is altered, there seems to be reduced crestal bone loss. Immediate loading allows immediate restoration of esthetics and function, reduces morbidity, and facilitates functional rehabilitation. Materials and methods: Three Morse cone connection implants were inserted in the right posterior mandible in a 29-year-old partially edentulous patient. The platform of the implant was inserted 2 mm below the level of the alveolar crest. After a 1-month loading period, the most distal mandibular implant was retrieved with a trephine bur for psychological reasons. ...

This study reports the case of a patient with a severely resorbed mandible who was treated without a bone graft, using short implants, internal rigid fixation, rhBMP-2 and @b-tricalcium phosphate. A 76-year-old woman, with a severely resorbed mandible (less than 3mm), reported a history of nearly 25years of complete edentulism and consecutive treatment failures, with total bilateral exposed inferior alveolar nerves and complete bone resorption of the inferior border in some areas. The treatment of choice was the placement of a 2.0mm thick unilock bone plate (MatrixMandible, Synthes Maxillofacial, Paoli, PA, USA), to reinforce the mandible. Eight short implants with a regular platform (Nobel Biocare, Goteborg, Sweden) were placed: three on the external oblique line on both sides and two on ...

Congenital lobar emphysema (CLE) is a cause of severe neonatal respiratory distress. Overexpansion of the affected pulmonary lobe in the fetus is due to narrowing of the airway, with a resultant 'ball-valve' effect. At birth, there may be delayed clearance of fetal lung fluid. Early chest radiographs show opacification of the hyperexpanded lobe. The CT findings in the immediate neonatal period have not been previously reported. We describe the imaging in a neonate with tetralogy of Fallot and absent pulmonary valve with secondary CLE. CT demonstrates the hyperexpanded lobe with initial thickening of the interlobular septa and alveolar ground glass attenuation, with subsequent clearing. This resorption of fetal lung fluid via the pulmonary interstitium should not be confused with interstitial lung disease. (orig.)

Background: The aim of this study was to evaluate the clinical outcomes and radiographic data of transcrestal sinus floor elevation (TSFE) of residual alveolar bone ?3?mm. Methods: Forty-six patients, edentulous in one or both maxillary posterior segments, were enrolled in this study. The residual alveolar ridge was measured. TSFE without bone grafting was performed. Three months after the first surgery procedure, 66 implants were placed without grafting material. A presurgical distance from the alveolar crest to the floor of the maxillary sinus and the amount of new radiopacity between the sinus floor and alveolar crest were measured from the mesial and distal surfaces of each dental implant surface. Results: After a mean follow-up period of 10.43?±?5.01 years (ranged from 5 to 16 years), a survival rate of 95.45% was reported. Mean bone levels at implant placement were 7.12?±?0.90?mm and, after 1 year, were 13.28?±?1.23?mm. They were stable over time, reporting an up to 16 years' value of 13.07?±?2.63?mm. Conclusions: The results of this retrospective clinical study confirmed the reliability of the TSFE procedure and the maintenance of bone levels without grafting procedures over time. PMID:20977614

Background: Alpha-Lipoic acid (ALA) and Vitamin C (Vit-C) are very important vitamin and powerful antioxidant which have been used for the treatment of many diseases. The present study aimed to investigate the role of ALA and Vit-C substances in the treatment of alveolar bone resorption in periodontal diseases. Methods: Thirty six Wistar albino male rats were randomly divided into four groups as follows: Control (C), experimental periodontitis group (PED), experimental periodontitis treated with ALA (ALA) and experimental periodontitis group treated with ALA+Vit-C combination (ALA+Vit-C). Experimental periodontitis was simulated by placing ligatures around the necks of teeth for 5 weeks. After ligature removal, PED group was given a single intra gastric dose of 1 ml saline, while ALA and ALA+Vit-C groups were treated with intra-gastric dose of 50 mg/kg of ALA and ALA+Vit-C for 15 days, respectively. Serum Bone Alkaline Phosphatase (B-ALP) levels and myeloperoxidase activity in gingival tissues were analyzed. In order to evaluate the osteoclast activation, expression of activated receptor activator nuclear factor kappa B ligand (RANKL) and bone density index (BDI) were examined stereologically in the bone sections obtained from the mandibles of the rats. Results: The results showed statistically significant differences between the PED group and antioxidant treated groups according to B-ALP, MPO, RANKL and BDI values (p<0.05). ALA and ALA+Vit-C treatments exhibited beneficial effects on the mesial/distal periodontal bone support at the ligature-induced periodontitis tooth areas. Conclusion: This study evidenced that ALA and Vit-C treatment provided therapeutic effects on inhibition of alveolar bone resorption and periodontal tissue destruction. PMID:22702517

Objective We describe the clinical results of mandibular augmentation with coronoid process bone grafts for dental implant insertion. Study Design Fifteen patients with vertical and transverse defects of the posterior alveolar process of the mandible were treated. All patients underwent mandibular rehabilitation with autogenous coronoid process bone grafts via minimal-access surgery. After 6 months, 40 dental implants were inserted. Results At the time of implant insertion, the grafted alveolar ridges showed mean transverse and vertical augmentations of 3.07 and 2.80 mm, respectively. At 24 months after implant surgery, the cumulative implant survival rate was 95% and mean marginal bone loss was 1.6 ± 0.18 mm. No complete bone graft loss or infection occurred. Conclusions Coronoid p...

Traumatic injuries may cause anatomic deficiencies in soft and hard tissues. These defects often result in the loss of attached mucosa and alveolar processes, which might reduce potential prosthesis support and require bone and skin grafting. As a result of major maxillofacial trauma, complete or partial avulsion of the palate may require extensive surgical and prosthodontic rehabilitation. The appropriate treatment for the maxillary defect demands a multidisciplinary approach by a team which consists of various fields of dentistry and medicine. The planning prostheses should replace not only missing teeth but also lost soft tissues and bone, and they should include the hard palate, residual alveolar ridges, and, in some instances, the soft palate. This paper describes the treatment procedures including plastic surgery operation procedures and prosthetic rehabilitation in a 19-year-old woman after her severe bicycle accident. PMID:12787220

Two-dimensional finite element analysis of stresses developed in the supporting tissues under complete dentures using teeth with different cusp angulations Statement of problem: The selection of appropriate teeth for complete denture occlusion is very important for long-term success, and adequate maintenance of the residual alveolar ridge. Purpose: The purpose of this study was to determine the stress generated underneath the complete denture by altering the cuspal angulations of the denture teeth. Material and methods: A two-dimensional finite element model of a coronal section of maxillary and mandibular complete dentures, mucosa and alveolar bone in the first molar region was designed. The occlusal aspect of the denture teeth was altered to make 33degree, 20degree, 0degree cuspal angula...

Abstract in spanish En el presente artículo se describe la técnica de aumento del piso del seno maxilar a través del reborde alveolar, mediante el uso de osteotomos en combinación con procedimientos de regeneración ósea guiada y uso de biomateriales de relleno. Se reporta el caso de una paciente femenina de 65 años de edad, con disminución de altura ósea del reborde alveolar, debido a la neumatización de los senos maxilares, asociada con moderada reabsorción ósea, a quien se le c (more) olocó a nivel del primer molar superior izquierdo implantes 3,5 x 11 mm IMTEC Endure Internal Hex System y se aplicó la técnica descrita de aumento del piso del seno maxilar. Mediante esta técnica es posible la elevación atraumática de la membrana sinusal, con bajo riesgo de lesionarla. Abstract in english In the present article, the technique of maxillary sinus floor increase through the alveolar ridge by using osteotomes in combination with bone regeneration guided procedures and the use of biomaterial fillings is described. It is reported the case of a 65 year old, female patient, with a decrease of alveolar ridge bone height due to the pneumatization of the maxillary sinus, associated with moderate bone re-absorption. The procedure consisted on the placement of a 3.5 x (more) 11 mm IMTEC Endure Internal Hex System implant, at the level of the superior left first molar and the application of the technique described before (maxillary sinus floor increase). By using this technique, an atraumatic elevation of the sinus membrane is possible with low risk of injuring it.

A case of an epulis in an 8-month-old boy is reported. The tumor was localized on the mandibular alveolar ridge and, according to the parents, was a recurrence of a congenital tumor excised when the boy was 2 months old. Microscopically, it was composed of many spindled or ovoid cells with vesicular nuclei and non-granular eosinophilic cytoplasm, and covered by acanthotic parakeratinized squamous epithelium with broad rete pegs. Immunohistochemically, the spindled and ovoid cells were intensely positive for vimentin and neuron-specific enolase, and negative for S-100 protein. The final diagnosis was spindle cell epulis. The possible correlation of this lesion with congenital granular cell epulis is discussed.

Ectodermal dysplasia (ED) is a hereditary disorder that affects ectodermal structures. The main clinical oral manifestations of ED include oligodontia and deficient alveolar ridges. This case report presents the oral rehabilitation of a 15-year-old female patient who never received an accurate diagnosis or appropriate dental care. Treatment included a combination of surgical intervention, a maxillary tooth-supported fixed detachable telescopic prosthesis, and an implant-supported mandibular fixed partial denture. The results showed a significant improvement in the esthetics, function, and psychological status of the patient. This article stresses the importance of appropriate care in providing an acceptable quality of life for patients with ED. PMID:22229591

Providing complete denture therapy to patients with atrophic residual alveolar ridges is challenging. Because these patients suffer ongoing diminution of the denture foundation, modern approaches often involve dental implant therapy as a means of improving the denture foundation and supplementing the mechanics of prosthesis support, retention, and stability. Regardless of implant availability, physiologically optimal denture contours and physiologically appropriate denture tooth arrangement should be achieved to maximize prosthesis stability, comfort, and function for patients. This article presents historical perspectives on the arrangement of denture teeth in the facial-lingual dimension and the contouring of complete denture polished surfaces. Additionally, a modern clinical technique i...

This study analysed the initial effects of the combination of oestrogen deficiency with a calcium-deficient diet on alveolar bone repair. Sixty-three 3-month-old female rats were either ovariectomized (OVX, n = 42) or sham-operated (SHAM, n = 21). Among the 42 ovariectomized rats, 21 received standard commercial food (OVX) and 21 received food with low calcium content (ESP). The mandibular first molars were extracted bilaterally 15 days after ovariectomy or sham surgery. The rats were weighed and killed at 7, 21 and 45 days after tooth extraction. The results were evaluated by descriptive microscopic analysis, histomorphometry of the trabecular and osteoid volume and mast cell counts. Analysis of the results indicated that trabecular volume and mast cell counts increased significantly over time, while osteoid volume decreased over time. Comparisons between the SHAM and OVX groups demonstrated no statistical differences, while comparison between the OVX and ESP groups indicated differences in trabecular volume and the number of mast cells. The data suggest that hormonal deficiency does not delay alveolar bone repair in OVX rats; however, oestrogen deficiency associated with calcium deficiency can lead to bone resorption through the activation of mast cells. PMID:22364763

Our aim was to investigate the efficacy of correction of an alveolar cleft with distraction osteogenesis using anchorage with a tooth-microimplant joint in a canine model, which was established in 12 adult mongrel dogs that were subsequently randomised into two groups (n=6 in each). The first group comprised dogs that had osteogenesis using anchorage with a tooth (tooth group), while in the second, anchorage with tooth-microimplant joint (microimplant group) was used. All animals were killed one month after completion of distraction. Samples were collected for gross observation and histological examination. There was a significant difference in the degree of movement of the anchorage teeth in the transport discs between the 2 groups (p<0.01). There was less prominent inclination and shift of the natural teeth in the transport disc and less bony resorption around the root in the microimplant group than in the tooth group. These changes were less remarkable in the microimplant group. Treatment of alveolar cleft by distraction osteogenesis using anchorage with a tooth-microimplant joint is practical, and yields better results. PMID:22209447

Periodontitis comprises a group of multifactorial diseases in which periodontopathogens accumulate in dental plaque and trigger host chronic inflammatory and immune responses against periodontal structures, which are determinant to the disease outcome. Although unusual cases of non-inflammatory destructive periodontal disease (NIDPD) are described, their pathogenesis remains unknown. A unique NIDPD case was investigated by clinical, microbiological, immunological and genetic tools. The patient, a non-smoking dental surgeon with excessive oral hygiene practice, presented a generalized bone resorption and tooth mobility, but not gingival inflammation or occlusion problems. No hematological, immunological or endocrine alterations were found. No periodontopathogens (A. actinomycetemcomitans, P. gingivalis, F. nucleatum and T. denticola) or viruses (HCMV, EBV-1 and HSV-1) were detected, along with levels of IL-1? and TNF-a in GCF compatible with healthy tissues. Conversely ALP, ACP and RANKL GCF levels were similar to diseased periodontal sites. Genetic investigation demonstrated that the patient carried some SNPs, as well HLA-DR4 (*0404) and HLA-B27 alleles, considered risk factors for bone loss. Then, a less vigorous and diminished frequency of toothbrushing was recommended to the patient, resulting in the arrest of alveolar bone loss, associated with the return of ALP, ACP and RANKL in GCF to normality levels. In conclusion, the unusual case presented here is compatible with the previous description of NIDPD, and the results that a possible combination of excessive force and frequency of mechanical stimulation with a potentially bone loss prone genotype could result in the alveolar bone loss seen in NIDPD. PMID:22437688

Abstract Introduction: Tooth loss reduces oral-health-related quality of life (OHRQoL) as assessed with the 14-item Oral Health Impact Profile questionnaire (OHIP-14). Objectives: This prospective multicenter case-control study sought to (i) establish OHRQoL in patients requiring a single implant in the anterior maxilla and to (ii) compare these changes following implant placement and immediate provisionalization in extraction sockets with healed alveolar ridges up to 1 year. Material and methods: Ninety-six patients were enrolled in the study with 102 single implants (OsseoSpeed- AstraTech) provisionalized immediately after placement in sockets or after placement in healed ridges. A final crown was cemented after 12 weeks. OHIP-14 was registered before surgery (baseline), after 1 (provisi...

C-src deficiency is characterized by osteopetrosis due to impaired bone resorption by hypofunctional osteoclasts and the resultant failure of tooth eruption. In preliminary observations, we frequently encountered erupted molars in c-src deficient mice unlike in other osteopetrotic animals. Here we examine the effects of c-src deficiency on the development of molar teeth with an emphasis on the spatial relation of growing teeth with the surrounding bones. In c-src deficient mice, the magnitude of tooth impaction differed considerably among the types of molars; all maxillary 1st molars were totally impacted deep in the alveolar sockets, whereas most mandibular 1st molars fully erupted into oral cavity. Distribution of osteoclasts in the alveolar bone was identical among all types of molars, and electron microscopy revealed signs of bone resorbing activity in these osteoclasts despite the absence of a ruffled border. From early development, the alveolar space was much narrower in the upper molar tooth germs than in the lower ones in both wild type and homozygous animals, and particularly so in the upper 1st molars. Current observations thus indicate a significant contribution of “hypofunctional osteoclasts” in c-src deficient mice in molar tooth development except for the upper 1st molars, which appear to require highly functional osteoclasts to gain sufficient space for them to grow normally. Taken together, these findings on the seemingly tooth-type specific effects of c-src deficiency on the development and eruption of molar teeth in c-src deficient mice can be attributed to the given differential spatial relation of the respective tooth germs with the surrounding bones in the presence of hypofunctional osteoclasts.   

New technologies that facilitate solid alveolar ridge augmentation are receiving considerable attention in the field of prosthodontics because of the growing requirement for esthetic and functional reconstruction by dental implant treatments. Recently, several studies have demonstrated potential advantages for stem-cell-based therapies in regenerative treatments. Mesenchymal stem/stromal cells (MSCs) are now an excellent candidate for tissue replacement therapies, and tissue engineering approaches and chair-side cellular grafting approaches using autologous MSCs represent the clinical state of the art for stem-cell-based alveolar bone regeneration. Basic studies have revealed that crosstalk between implanted donor cells and recipient immune cells plays a key role in determining clinical success that may involve the recently observed immunomodulatory properties of MSCs. Part II of this review first overviews progress in regenerative dentistry to consider the implications of the stem cell technology in dentistry and then highlights cutting-edge stem-cell-based alveolar bone regenerative therapies. Factors that affect stem-cell-based bone regeneration as related to the local immune response are then discussed. Additionally, pre-clinical stem cell studies for the regeneration of teeth and other oral organs as well as possible applications of MSC-based immunotherapy in dentistry are outlined. Finally, the marketing of stem cell technology in dental stem cell banks with a view toward future regenerative therapies is introduced. PMID:23137671

The aim of this study is to evaluate the anesthetic efficacy of mylohyoid and buccal nerve anesthesia at the posterior edentulous mandible versus regional anesthetic block to the inferior alveolar nerve in dental implant surgery. The study was composed of 2 groups. In the first group (group A), 14 voluntary adults (7 female and 7 male) received local infiltrations of 1 mL articaine HCl 4% with epinephrine 1/200,000 to the ipsilateral mylohyoid and buccal nerves. In the second group (group B, control; 9 female and 5 male adults), the inferior alveolar and the buccal nerve blocks were performed. Visual analog scales were obtained from patients to determine the level of pain during incision, drilling, implant placement, and suturing stages of implant surgery. A combination of buccal and mylohyoid nerve block offered an acceptable level of anesthesia. Two patients from group A stopped the ongoing surgery and had extraregional anesthesia by inferior alveolar nerve block. In group B, patients were operated on successfully. Local anesthetic infiltrations of the mylohyoid and the buccal nerve may be considered alternative methods of providing a convenient anesthetic state of the posterior mandibular ridge. PMID:20662675

Abstract Background: Many patients and clinicians would prefer a synthetic particulate bone replacement graft, but most available alloplastic biomaterials have limited osteogenic potential. An alloplast with increased regenerative capacity would be advantageous for the treatment of localized alveolar ridge defects.Methods: This prospective, randomized controlled pre-clinical trial utilized six female foxhounds to analyze the osteogenic impact of different formulations of BCP in combination with an HA-collagen membrane and their ability to reconstruct deficient alveolar ridges for future implant placement. The grafted sites were allowed to heal 3 months, and then trephine biopsies were obtained to perform light microscopic and histomorphometric analyses. Results: All treated sites healed well with no early membrane exposure or adverse soft tissue responses during the healing period. The grafted sites exhibited greater radiopacity than the surrounding native bone with biphasic calcium phosphate (BCP) particles seen as radiopaque granules. The graft particles appeared to be well-integrated and no areas of loose particles were observed. Histologic evaluation demonstrated BCP particles embedded in woven bone with dense connective tissue/marrow space. New bone growth was observed around the graft particles as well as within the structure of the graft particulate. There was intimate contact between the graft particles and newly formed bone, and graft particles were bridged by the newly formed bone in all biopsies from the tested groups. Conclusions: The present study results support the potential of these BCP graft particulates to stimulate new bone formation. Clinical studies are recommended to confirm these preclinical findings. PMID:23106233

To investigate changes in the characteristics of edentulous mucosa in the alveolar ridge with aging, we applied pressure to the mucosa of the alveolar ridge in subjects of various ages and evaluated the recovery amount and time after the pressure was removed. Twenty-three subjects ranging from 23 to 79 years of age, who had lost the first mandibular molar tooth, were selected. Displacing pressure was applied to the mucosa corresponding to the mandibular first molar region. After release the pressure, we measured the recovery amount of mucosa from its displacement, which was expressed as the movement of a target which had been placed on the mucosa as measured by an indirect displacement measurement device. The levels of displacement were set at 0.1mm, 0.2 mm and 0.3 mm, and the time to achieve the selected displacement level was set at 1 second. The initial recovery of the mucosa immediately after the pressure has been released was designated as the initial recovery amount, and the time needed for recovering to 90% of the previous state was designated as the final recovery time. Then we investigated the relationships between the measures of the initial recovery amount, the final recovery time, and the subjects' ages. The initial recovery amount of mucosa was lower and the final recovery time was longer in older subjects, and this tendency was exaggerated when the displacement was increased.   

INTRODUCTION: Atrophy of the alveolar bone is an irreversible multifactorial phenomenon, the rate of which varies between individuals and between the jaws. This atrophy of the alveolar ridges presents severe limitations for the oral rehabilitation of the edentulous patients and poses a clinical challenge to the prosthodontists and implant surgeons. The present research aimed to investigate whether the median-palate of elderly edentulous subjects is anatomically suitable for implant placement. MATERIALS AND METHODS: A total of 32 samples were harvested from the maxillae of 16 human cadavers. One dentate male subject was included for contrast. Bone quality and quantity were analysed at two regions: the median-palate and the edentulous maxillary alveolar ridge. Samples were scanned through micro-CT, and the region of analysis (ROA) identified and dissected. Bone volume to tissue volume ratio (%BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp) and trabecular bone pattern factor (Tb.Pf) were evaluated for the two regions using Skyscan CTAn(®) . RESULTS: The results of bone volume fraction obtained from CTAn(®) of the median-palatal region show higher values than the respective premolar sites in 12 of 15 (80%) edentulous samples. However, this difference was statistically non-significant (P = 0.06). Similarly, the trabecular number for 10 of 15 samples (66.6%) from the median-palate shows greater values than the respective premolar site (P = 0.07). Trabecular thickness of 10 of 15 (66.6%) premolar samples is larger than in the median-palatal region. However, these differences were also statistically non-significant (P = 0.25). Statistically significant difference (P = 0.04) was found between the Tb.Sp values of the two regions. CONCLUSION: The results indicate that the anterior median-palate is structurally better than their respective maxillary premolar region in elderly edentulous persons, and an implant can be placed to anchor an overdenture. The best site for a wide-body implant was established to be 6-8 mm posterior to the incisive foramen in elderly edentulous patients. PMID:23075081

Abstract in english OBJECTIVE: The purpose of this study was to evaluate the accuracy of relative measurements from the roof of the mandibular canal to the alveolar crest in multislice (multidetector) computed tomography (MDCT) and single-slice computed tomography (SSCT). MATERIAL AND METHODS: The sample consisted of 26 printed CT films (7 SSCT and 19 MDCT) from the files of the LABI-3D (3D Imaging Laboratory) of the School of Dentistry of the University of São Paulo (FOUSP), which had been (more) acquired using different protocols. Two observers analyzed in a randomized and independent order a series of 22 oblique CT reconstructions of each patient. Each observer analyzed the CT scans twice. The length of the mandibular canal and the distance between the mandibular canal roof and the crest of the alveolar ridge were obtained. Dahlberg test was used for statistical analysis. RESULTS: The mean error found for the mandibular canal length measurements obtained from SSCT was 0.53 mm in the interobserver analysis, and 0.38 mm for both observers. On MDCT images, the mean error was 0.0 mm in the interobserver analysis, and 0.0 and 0.23 mm in the intraobserver analysis. Regarding the distance between the mandibular canal roof and the alveolar bone crest, the SSCT images showed a mean error of 1.16 mm in the interobserver analysis and 0.66 and 0.59 mm in the intraobserver analysis. In the MDCT images, the mean error was 0.72 mm in the interobserver analysis and 0.50 and 0.54 mm in the intraobserver analysis. CONCLUSION: Multislice CT was demonstrated a more accurate method and demonstrated high reproducibility in the analysis of important anatomical landmarks for planning of mandibular dental implants, namely the mandibular canal pathway and alveolar crest height.

Abstract in spanish Es frecuente encontrarnos con deformidades o defectos en la cresta alveolar en el frente antero-superior que dificultan la restauración protésica de la zona afectada. El tratamiento de estos defectos intenta la reconstrucción de los tejidos duros y blandos del reborde desdentado para conseguir una dentición adecuada en cuanto a estética, función y salud. Los defectos leves o moderados con poca pérdida de tejido duro se pueden resolver generalmente con aumento de te (more) jidos blandos. Sin embargo, los casos más graves o con pérdida importante de hueso en los que se opte por tratamiento implantológico es necesario el aumento de los tejidos duros y blandos, simultáneo o no a la colocación de fijaciones, en una o varias etapas. El presente artículo describe un procedimiento quirúrgico, mediante un injerto pediculado de tejido conectivo palatino, para el aumento del tejido blando en combinación con procedimientos de regeneración ósea guiada, en defectos localizados en el frente anterior del maxilar superior. Abstract in english Frequently, we encounter alveolar ridge defects or deformities in the maxillary anterior region that make it difficult to obtain optimal aesthetic prosthetic results. The correction of ridge defects tries to reconstruct the hard and soft tissues of the edentulous ridge in order to achieve aesthetics, function and health. Generally, small or moderate defects with limited loss of hard tissues may be successfully treated with soft tissue augmentations. However, in more sever (more) e cases or in those with important bone loss in which implant treatment is chosen, both soft and hard tissues have to be augmented, either simultaneously with implant placement or not, in one or several stages. This study describes a surgical procedure with a palatal pedicle connective tissue graft for soft tissue augmentation in combination with GBR procedures in defects located in the maxillary anterior region.

Background: The presence of localized defects and/or small amounts of bone below the maxillary sinus is a common finding, which may compromise implant placement. There is therefore a need for predictable techniques for bone augmentation in such situations. Purpose: The study aims to clinically and histologically evaluate a porcine bone (PB) substitute used for augmentation of the alveolar crest or the maxillary sinus floor prior to or in conjunction with implant placement. Materials and Methods: Nineteen patients were treated with a porcine bone substitute and barrier membranes (OsteoBiol, Tecnoss Dental, Turin, Italy) for lateral bone augmentation (Group 1a) and healing of bone defects (Group 1b) or for augmentation of the maxillary sinus floor using either a replaceable (Group 2a) or an infractured bone window (Group 2b). A total of 34 implants (Neoss Ltd., Harrogate, UK) were placed in conjunction or 5 to 7 months after the procedure. Implants were followed with implant stability measurements at placement and abutment connection, and with intraoral radiographs at abutment connection and after at least 1 year of loading. A biopsy for histology and morphometry was taken at the first reentry operation. Results: All but one of the procedures was successful (94.7%) as one maxillary sinus procedure (Group 2a) resulted in insufficient bone for implant placement. One of the 34 implants failed, giving an implant survival rate of 97.1% after 1 year. Implant stability measurements showed a mean stability of 71.9?±?7.7 implant stability quotient (ISQ) at placement, which significantly increased to 75.3?±?6.8 ISQ at abutment connection (p?=?.03). The average bone loss was 0.5?±?0.7?mm during 1 year. Histology revealed new bone formation at the PB surface, which formed bridges between particles and between particles and preexisting bone. The presence of scalloped resorption lacunae and new osteons inside the particles indicated ongoing resorption/remodeling of the particles. The histomorphometric analyses showed that the total specimen area consisted of, in average, 56.5?±?15.7% mineralized tissue of which 24.8?±?13.9% of the total area was PB particles. Conclusion: This study showed good clinical results when using a PB substitute and barrier membranes for augmentation of the alveolar crest and maxillary sinus. Histology revealed bone condensation properties and indicated that the material can be resorbed with time. PMID:20977615

Abstract in english Periodontitis comprises a group of multifactorial diseases in which periodontopathogens accumulate in dental plaque and trigger host chronic inflammatory and immune responses against periodontal structures, which are determinant to the disease outcome. Although unusual cases of non-inflammatory destructive periodontal disease (NIDPD) are described, their pathogenesis remains unknown. A unique NIDPD case was investigated by clinical, microbiological, immunological and gene (more) tic tools. The patient, a non-smoking dental surgeon with excessive oral hygiene practice, presented a generalized bone resorption and tooth mobility, but not gingival inflammation or occlusion problems. No hematological, immunological or endocrine alterations were found. No periodontopathogens (A. actinomycetemcomitans, P. gingivalis, F. nucleatum and T. denticola) or viruses (HCMV, EBV-1 and HSV-1) were detected, along with levels of IL-1? and TNF-a in GCF compatible with healthy tissues. Conversely ALP, ACP and RANKL GCF levels were similar to diseased periodontal sites. Genetic investigation demonstrated that the patient carried some SNPs, as well HLA-DR4 (*0404) and HLA-B27 alleles, considered risk factors for bone loss. Then, a less vigorous and diminished frequency of toothbrushing was recommended to the patient, resulting in the arrest of alveolar bone loss, associated with the return of ALP, ACP and RANKL in GCF to normality levels. In conclusion, the unusual case presented here is compatible with the previous description of NIDPD, and the results that a possible combination of excessive force and frequency of mechanical stimulation with a potentially bone loss prone genotype could result in the alveolar bone loss seen in NIDPD.

Abstract in portuguese Diante do diagnóstico de uma arcada maxilar esqueleticamente atrésica, o tratamento de escolha geralmente é a expansão ortopédica da maxila, envolvendo a separação da sutura palatina mediana. A avaliação dessa sutura era basicamente realizada por meio da radiografia oclusal superior, limitando sua análise em norma frontal. Da mesma forma, quantificar essa atresia radiograficamente nas telerradiografias cefalométricas sempre foi um obstáculo para o clínico, de (more) vido à grande sobreposição das estruturas faciais. O advento da tomografia computadorizada na Odontologia tem transformado a forma de diagnóstico devido à alta precisão na avaliação das dimensões das estruturas faciais, possibilitando quantificar de maneira fiel o comportamento das hemimaxilas, a inclinação dentária, a formação óssea na sutura nos três planos do espaço, assim como a reabsorção óssea alveolar e demais consequências da expansão palatina Abstract in english Whenever a maxillary arch is diagnosed as skeletally atresic the treatment of choice is usually maxillary orthopedic expansion, involving separation of the midpalatal suture. Basically, this suture used to be assessed with the aid of a maxillary occlusal radiograph, which limited its posteroanterior evaluation. Similarly, quantifying this atresia in cephalometric x-rays always posed an obstacle for clinicians owing to considerable superimposition of facial structures. Wit (more) h the advent of computed tomography, this technology has revolutionized diagnostic methods in dentistry because it provides high dimensional accuracy of the facial structures and a reliable method for quantifying the behavior of the maxillary halves, tooth inclination, bone formation at the suture in the three planes of space, as well as alveolar bone resorption and other consequences of palatal expansion

The osteoclasts are the cells responsible for bone resorption. Matrix metalloproteinases (MMPs) appear crucial for this process. To identify possible MMP expression in osteoclasts, we amplified osteoclast cDNA fragments having homology with MMP genes, and used them as a probe to screen a rabbit osteoclast cDNA library. We obtained a cDNA of 1,972 bp encoding a polypeptide of 582 amino acids that showed more than 92% identity to human, mouse, and rat membrane-type 1 MMP (MT1-MMP), a cell surface proteinase believed to trigger cancer cell invasion. By northern blotting, MT1-MMP was found to be highly expressed in purified osteoclasts when compared with alveolar macrophages and bone stromal cells, as well as with various tissues. In situ hybridization on bone sections showed that MT1-MMP is expressed also in osteoclasts in vivo. Antibodies recognizing MT1-MMP reacted with specific plasma membrane areas corresponding to lamellipodia and podosomes involved, respectively, in migratory and attachment activities of the osteoclasts. These observations highlight how cells might bring MT1-MMP into contact with focal points of the extracellular matrix, and are compatible with a role of MT1-MMP in migratory and attachment activities of the osteoclast.

Actinomycosis occurs most frequently in the cervicofacial region. The disease commonly affects soft tissue adjacent to the jawbone, however, bone involvement is rare. We report a case of actinomycotic osteomyelitis of the maxilla that was suspected of being a malignant tumor.In July 2005, a 71-year-old woman presented to our hospital complaining of pain in the right maxillary molar region. She had consulted a dental office in March 2005 because of mobility of her teeth, where she had undergone tooth extraction of the right upper first molar. She had noted spontaneous pain in the right maxilla about one week previously. Clinical examination demonstrated swelling and redness of the buccal gingiva and prominent swelling of the palate in the right maxilla, with granulomatous tissue at the extraction socket. Radiograph showed a moth-eaten appearance in the right maxilla and CT disclosed ill-defined bone resorption of the alveolar process and palate.Malignant tumor was suspected. Biopsy demonstrated granulation tissue with necrotic bone and colonies of microorganisms histopathologically. A diagnosis of actinomycotic osteomyelitis of the maxilla was made. Sequestrectomy was performed, followed by intravenous ampicillin. The postoperative course has been satisfactory during follow-up for 3 years to date.   

Abstract Objective. The aim of this study was to use intra-oral radiographs to evaluate changes in marginal bone levels around three different implant designs after 1 year. Materials and methods.Three implant designs; two with a straight and one with a conical design, were placed adjacent to each other in the partially edentulous areas of 25 patients. The patients received 46 implants with a straight design (All fit SSO and SPI-element) and 29 implants with a conical design (SPI-contact). Two-way repeated analysis of variance (ANOVA) was used to evaluate the marginal bone changes in each group at 12 months follow-up (p < 0.05). Results. None of the implants had failed by the end of this study. After 12 months, significant differences were noted in the amount of alveolar bone loss recorded between the All fit SSO and SPI implants (p < 0.05). Mean crestal bone loss was 0.88 ± 0.43 mm for the All fit, 0.61 ± 0.34 mm for the SPI contact and 0.54 ± 0.27 mm for the SPI element implants. Conclusions. The results of this study demonstrate that straight (cylindrical) implants with shorter high polish surface displayed less bone resorption. PMID:23004236

Background: Periodontitis is an inflammatory process caused by a specific group of microorganisms, resulting in the destruction of the tooth-supporting tissue and the resorption of the alveolar bone. Therefore, periodontitis has been considered a risk factor for preeclampsia because infection is one of the factors involved in the etiology and pathogenesis of preeclampsia. The aim of the present study is to determine whether periodontitis is a risk factor for preeclampsia and to identify other possible risk factors. Methods: A case-control study was performed with 574 puerperae under care at the university hospital at the Universidade Federal de Pernambuco in the city of Recife, Brazil. Data collection was preceded by a training exercise and a pilot study. Biologic and socioeconomic data were collected along with medical and dental records. A periodontal examination was performed on all dental elements to determine probing depth and gingival recession. The association between periodontitis and preeclampsia was first adjusted for the variables within each block, and adjusted for the variables of all blocks in the final multivariate model. Results: The multivariate logistic regression analysis showed that, after adjustment for other risk factors, periodontitis remained an independent risk factor for preeclampsia (adjusted odds ratio [OR] = 8.60, confidence interval [CI] = 3.92 to 18.88, P studied, periodontitis was a risk factor for preeclampsia. PMID:22309175

doi:10.1111/j.1741-2358.2009.00343.x - Implant-supported overdenture in an elderly patient with Huntington-s disease Huntington-s disease is a hereditary, progressive, neuro-degenerative disorder characterised by increasingly severe motor impairment, cognitive decline and behavioural manifestations leading to functional disability. Dyskinesia and hyperkinesia of the tongue and the peri-oral musculature make it impossible for the patient to wear a conventional complete denture, despite an adequate alveolar ridge. The present paper reports on a patient with Huntington-s disease who was rehabilitated with a mandibular overdenture supported by two endosteal implants. One year follow-up examination showed that the prosthesis was stable and there was considerable improvement in the patient-s mas...

Statement of problem Resilient (nonrigid) and non-resilient (rigid) attachments are used in extension base partial removable dental prostheses for retention. However, the biomechanical effects of these 2 types of retainers on the terminal abutment and supporting tissues, which may influence clinical treatment planning, have not been compared. Purpose The purpose of this study was to compare the mechanical effects of 2 types of extracoronal attachments (rigid and nonrigid) in distal extension removable partial prostheses on the alveolar ridge and abutment tooth periodontal ligament. Material and methods A finite element model of a human left mandible edentulous arch distal to the second premolar was fabricated. The second premolar was the terminal abutment for an attachment-retained denture...

In order for a dental implant to be restored optimally, it must be placed in an ideal anatomic position. However, this is not always possible, since physiological wound healing after tooth removal, often results in hard and soft tissue changes which ultimately compromises ideal implant placement. With the aim of minimising the need for tissue augmentation, several alveolar ridge preservation (ARP) techniques have been developed. These often require the use of grafting material and therefore increase the risk of disease transmission. Leukocyte and platelet-rich fibrin (L-PRF) is a newly developed platelet concentrate that is prepared from the patient's own blood. Clinical research has indicated that it improves wound healing and stimulates bone formation. We present a case where L-PRF was successfully used in an ARP procedure to facilitate implant placement in a compromised extraction socket. PMID:16783734

Abstract Background: Following tooth extraction and immediate implant installation, the edentulous site of the alveolar process undergoes substantial bone modeling and the ridge dimensions are reduced. Objective: The objective of the present experiment was to determine whether the process of bone modeling following tooth extraction and immediate implant placement was influenced by the placement of a xenogenic graft in the void that occurred between the implant and the walls of the fresh extraction socket. Material and methods: Five beagle dogs about 1 year old were used. The 4th premolar in both quadrants of the mandible (4P4) were selected and used as experimental sites. The premolars were hemi sected and the distal roots removed and, subsequently, implants were inserted in the distal soc...

Abstract Instances of unoperated cleft lip and/or palate (CLP) in adult or elderly patients are still seen in developing countries. This paper presents the multidisciplinary management and the personal identity revival of a 72-year-old patient with unoperated unilateral complete cleft lip. The facial deformity was characterized by a protrusion of the excess of orbicularis oris muscle, irregularities of the upper lip, nose distortion, and septum deviation to the cleft side. The patient was edentulous with the maxillary alveolar ridge collapsed and an associated fistula. The cleft lip was repaired using the Tennison-Randall technique and complete dentures were delivered after the oroantral fistula had been closed. The patient was very pleased with the improvement in speech and eating and she...

There have been only a few published reports on the dental-facial effects of radiation therapy and the subsequent oral management of these patients. A case involving a 13-year-old black male patient with a history of rhabdomyosarcoma is presented. The patient received 4,050 rads of radiation to the right middle ear when he was 2 years of age. His residual medical and dental difficulties are apparently complications from the initial therapy. Examination of the oral cavity revealed bimaxillary micrognathia and marked loss of vertical dimension. A Class II facial profile with Class I molar relationship was observed. The mandible was thin and hypoplastic, with a small knife-edge alveolar ridge. The remaining eighteen erupted permanent teeth were very mobile, and root development had ceased after only initial formation. All of the teeth except the first permanent molars were extracted, and immediate partial dentures were inserted at the time of surgery. A discussion of therapeutic considerations follows the case report.

PurposeTo investigate the use of an internal self-activated distraction device made of titanium-nickel memory alloy to augment the mandibular alveolar ridge. Materials and MethodsTwelve adult mongrel canines were randomly divided into 4 groups. Groups I and II were sacrificed 1 month and 3 months after distraction, respectively. In group III (distraction-planting group), 2 implants were placed on both sides of the mandible 3 months after distraction. In group IV (control group), no implants were placed. X-rays were taken and histologic research was performed. ResultsWhen the distraction device was in place, the transport segments were lifted up 3.0 to 4.5 mm immediately, and a range of 7.5 to 11.5 mm of augmentation was reached after 3 to 5 days of device activation. X-rays showed that bon...

This study evaluated the effects of Escherichia coli-derived rhBMP-2 (ErhBMP-2) coated onto anodized implants to stimulate bone formation, osseointegration and vertical bone growth in a vertical bone defect model. Six young adult beagle dogs were used. After a 2-month bone healing period, anodized titanium implants (8mm in length) were placed 5.5mm into the mandibular alveolar ridge. Eighteen implants coated with ErhBMP-2 (BMP group) and another 18 uncoated implants (control group) were installed using a randomized split-mouth design. The implant stability quotient (ISQ) values were measured. Specimens were fabricated for histometric analysis to evaluate osseointegration and bone formation. The ISQ values at 8 weeks after implant placement were significantly higher in the BMP group than in...

A 61-years-old woman had macroglossia due to acromegaly with complaints of dyspneu at a lying sleeping position and complaints of speech and dysphagia. At the age of 55 years she was diagnosed with acromegaly induced by a adenoma of the pituitary gland, which had been removed surgically. The treatment of macroglossia included tongue reduction, removal of the remaining mandibular teeth with severe periodontal attachment loss, huge reduction of the residual alveolar ridge, immediate implant insertion, fabrication of implant-supported overdentures, and logopedic treatment. The speech improved significantly and the patient could sleep again in a lying position. Clinically, acromegaly is diagnosed on clinical signs, such as the morphology and the protrusion of the tongue. Often, macroglossia is a secondary symptom of a systemic disease, needing causal treatment. If surgical reduction of the tongue is indicated, also enlargement of the oral cavity should be considered. PMID:20614796

The aim of this study was to investigate the healing of human extraction sockets filled with ?-tricalcium phosphate and type I collagen (?-TCP/Clg) cones with or without a barrier membrane. Twenty patients were divided in two groups: (A) ?-TCP/Clg non-membrane and (B) ?-TCP/Clg + barrier membrane. Clinical examination and biopsies from the grafted sites were collected 9 months later. Bone samples were analyzed using histomorphometry and immunohistochemistry. The horizontal dimension of the alveolar ridge was significantly reduced 9 months after socket preservation in the non-membrane group. There was bone formation with no significant differences between the two groups in the areas occupied by new bone (A?=?42.4%; B?=?45.3%), marrow (A?=?42.7%; B?=?35.7%), or residual graft (A?=?9.7%; B?=?...

Purpose The aim of the present study was to investigate the healing, integration, and maintenance of autogenous onlay bone grafts and implant osseointegration either loaded in the early or the delayed stages. Materials and Methods A total of 5 male dogs received bilateral blocks of onlay bone grafts harvested from the contralateral alveolar ridge of the mandible. On one side, the bone block was secured by 3 dental implants (3.5 mm × 13.0 mm, Osseospeed; AstraTech AB, Mölndal, Sweden). Two implants at the extremities of the graft were loaded 2 days after installation by abutment connection and prosthesis (simultaneous implant placement group); the implant in the middle remained unloaded and served as the control. On the other side, the block was fixed with 2 fixation screws in...

ObjectivesTo compare the accuracy of cone-beam computerized tomography (CBCT) and multislice CT (MSCT) for linear jaw bone measurements.Study designAn ex vivo formalin-fixed human maxilla was imaged with both CBCT (Accuitomo 3D; Morita, Kyoto, Japan) and MSCT (4-slice Somatom VolumeZoom and 16-slice Somatom Sensation 16; Siemens, Erlangen, Germany). The MSCT images were reconstructed using different reconstruction filters to optimize bone visualization (U70u and U90u for VolumeZoom, H30s and H60s for Sensation 16). Before scanning, triplets of small gutta-percha markers were glued onto the soft tissues overlying the maxillary bone on the top and on both sides of the alveolar ridge to define a set of reproducible linear measurements in 11 planes. Image measurements were performed by 2 obser...

Patients with head and neck squamous cell carcinoma (SCC) are at risk of developing additional tumors in the head and neck. The detection of a late lymph node metastasis poses a problem to the clinician: it could be a delayed regional metastasis or a new metastasis from a yet unknown second primary tumor. Differentiation between metastasis and recurrence of primary tumors versus second primary tumor may be difficult because all lesions have the histologic appearance of SCC. Differentiation between these possibilities, however, carries important differences in therapeutic and prognostic consequences. In the following case report we present an unusually late regional lymph node metastasis in a patient who was treated 4 years earlier for an SCC in the inferior alveolar ridge. The purpose of the present study was to apply mitochondrial DNA D-loop analysis to assess the clonal relationship between oral tumor and node metastasis. PMID:22819335

Abstract Purpose: The purpose of this study was to evaluate the quality and quantity of augmented bone following alveolar ridge reconstruction with titanium mesh and autogenous particulate bone graft for implant placement in terms of the preoperative bone defect. Materials and Methods: Forty-one patients (50 sites) rehabilitated between September 2000 and May 2009 with autogenous particulate intraoral bone or iliac cancellous bone marrow grafts and micro-titanium meshes were enrolled. We classified the bone defects by means of shape as complex horizontal-vertical (HV), horizontal (H), and socket (S) types, and the augmented bone was evaluated based on preoperative computed tomographic data. The postsurgical complications were assessed during the healing period and after implant superstruct...

Objective: This case report was aimed at primary clinical experience concerning surgical extraction of a displaced tooth with the help of the Er:YAG laser based on refined computer-assisted presurgical planning. Methods: The case refers to the extraction of a displaced maxillary canine in a female patient. For the osteotomy, a pulsed Er:YAG laser was applied with pulse energy of 500 mJ, pulse duration of 250 sec and pulse frequency of 12 Hz. The fiber tip (1000 m) was kept with a 1-2 mm distance to the bone surface. Refined presurgical computer-assisted planning was performed with regard to minimization of bone loss, especially for the sake of preservation of the alveolar ridge. Based on a detailed three-dimensional (3D) reconstruction of the patient's anatomy, dynamical simulations of a b...

There are very few evidences on the extramandibular course (EMC) of the inferior alveolar nerve (IAN). We report here two such cases. The first one was encountered at dissection, in a human adult female cadaver where the right IAN terminal division was identified in the premolar region, above a severely atrophied mandibular body. The second case was a patient evaluated by cone-beam CT, who presented with an extremely atrophic mandible with bilateral extramandibular courses of the IANs. Such severe atrophy of the mandible may be considered as residual ridge class 7 along with the existing Atwood classes. EMCs of the IAN may not only occur in extreme mandibular atrophy, but also in dentate mandibles. In edentulous mandibles, an extramandibular IAN may complicate local surgical procedures or ...

Purpose: Anatomical variations of the maxillary sinus determine the degree of difficulty in performing sinus augmentation. While some variations, e.g. the septum and morphology of the sinus have been extensively studied, the structure of the medial wall has never been investigated. The aims of this study were: 1) to measure the location and angulation of the palatonasal recess (PNR) on the medial wall and 2) to identify risk sites that are related to the shape of the PNR. Materials and Methods: Cone beam computed tomography (CBCT) scans were screened from the school database. Edentulous sites were selected with less than 10 mm between the floor of the maxillary sinus and the alveolar crest. The residual ridge height (RH), the distance between the PNR and the alveolar crest, and the angulation of the PNR were measured on the selected sagittal planes. The percentage of sites (risk sites) with the recesses that were less than 90 degrees and less than 15 mm from the alveolar crest were calculated. The PNR location and angulation were compared among premolar and molar edentulous sites. Results: Two hundred and seventy four sites were studied. The mean PNR location was 14.2±2.8, 13.1±2.2, and 12.5±2.5 mm for the 2(nd) premolar, 1(st) molar and 2(nd) molar sites, with significant differences between the 2(nd) premolar and 2(nd) molar sites. The mean PNR angulation was 109.8 ± 25.3, 121.6 ± 22.1, and 144.9 ± 23.1 degrees in the correspondent sties, with significant differences between the study site groups. The percentage of the risk sites was 15%, 8.2% and 2.4% in the 2(nd) premolar, 1(st) molar and 2(nd) molar sites. Conclusion: Maxillary sinuses with acute-angled palatonasal recesses might present a challenge for performing sinus augmentation. Therefore, this anatomic structure should be carefully evaluated. PMID:23106503

Abstract in english OBJECTIVES: The non-homogenous aspect of periodontal ligament (PDL) has been examined using finite element analysis (FEA) to better simulate PDL behavior. The aim of this study was to assess, by 2-D FEA, the influence of non-homogenous PDL on the stress distribution when the free-end saddle removable partial denture (RPD) is partially supported by an osseointegrated implant. MATERIAL AND METHODS: Six finite element (FE) models of a partially edentulous mandible were creat (more) ed to represent two types of PDL (non-homogenous and homogenous) and two types of RPD (conventional RPD, supported by tooth and fibromucosa; and modified RPD, supported by tooth and implant [10.00x3.75 mm]). Two additional Fe models without RPD were used as control models. The non-homogenous PDL was modeled using beam elements to simulate the crest, horizontal, oblique and apical fibers. The load (50 N) was applied in each cusp simultaneously. Regarding boundary conditions the border of alveolar ridge was fixed along the x axis. The FE software (Ansys 10.0) was used to compute the stress fields, and the von Mises stress criterion (svM) was applied to analyze the results. RESULTS: The peak of svM in non-homogenous PDL was higher than that for the homogenous condition. The benefits of implants were enhanced for the non-homogenous PDL condition, with drastic svM reduction on the posterior half of the alveolar ridge. The implant did not reduce the stress on the support tooth for both PDL conditions. Conclusion: The PDL modeled in the non-homogeneous form increased the benefits of the osseointegrated implant in comparison with the homogeneous condition. Using the non-homogenous PDL, the presence of osseointegrated implant did not reduce the stress on the supporting tooth.

Abstract in spanish La regeneración ósea guiada (ROG) actualmente es considerada una terapia de gran importancia en Implantología para promover la regeneración de hueso en defectos óseos maxilares con la finalidad de crear un lecho adecuado para el posicionamiento de implantes. La ROG se basa en el uso de membranas reabsorbibles y no reabsorbibles en combinación con biomateriales de relleno como hueso autólogo, homólogo, heterólogo o materiales aloplásticos con funciones de barrera (more) mecánica, tendientes a excluir de la zona de reparación células epiteliales y conjuntivas, permitiendo la invasión de células osteoprogenitoras. En este artículo se presenta el caso clínico de un paciente al que se le realizó aumento vertical y horizontal de cresta ósea alveolar mediante regeneración ósea guiada en asociación con la colocación de implantes oseointegrados. Abstract in english Guide Bone Regeneration has been used widely in implantology for enhancing bone healing to optimize implant placements in the maxillary. The GBR is a technique that uses resorbable and non-resorbable membranes in combination with other filling biomaterials as autologous, homologous or heterologous bone graft, or aloplastic materials as mechanic barriers that prohibit the migration of connective and epithelial cells, enabling the osteogenic cells invasion in bone defects. (more) In the present study a clinic case of vertical and horizontal augmentation of alveolar ridge with guided bone regeneration in association with dental implants was reported.

Augmentation of alveolar bone after tooth extraction is beneficial for subsequent prosthetic treatment. Simvastatin, a therapeutic drug for hypercholestemia, stimulates BMP-2 expression in osteoblasts and local application of simvastatin augments bone. The purpose of the present study is to examine whether local application of alpha-tricalcium phosphate containing simvastatin augments the bone of the tooth-extracted site. Porous ?-TCP rods containing different doses of simvastatin (0, 0.25, 0.50, 1.0mg) were prepared. The right mandibular incisors of rats were extracted. The tooth sockets were filled with one of the rods in the experimental groups and were not filled with the material in the control group. Animals were sacrificed at 4 and 8 weeks and the tooth-extracted sites were analyzed with soft X-ray photography, dual-energy bone absorptiometry and micro CT, and histologically examined. Bone mineral content and bone width of the tooth extracted site were significantly higher in 0.5mg and 1.0mg groups at 4 weeks and in 1.0mg group at 8 weeks than those of the control and 0mg groups. Histologically, extensive new bone formation was observed outside of the socket walls in simvastatin-applied experimental groups. The present results indicate that local application of simvastatin with ?-TCP would be potential to preserve alveolar ridge after tooth extraction although further studies are required.   

OBJECTIVE: The purpose of this paper was to find a correlation between laser doppler flowmetry (LDF) and the bone mineral density quotient (BMDQ) to evaluate irradiated bone quality preoperatively. MATERIALS AND METHODS: Premolars and molars were extracted from six minipigs. After a three-month healing period, three animals received irradiation at a total dose of 24 Gy. Three months after irradiation, quantitative computed tomography was performed using a calibration bone phantom to determine the 120-position BMDQ in the alveolar bone. A drill template was created to define the exact location for measurement. LDF was then recorded after osteotomy of the residual alveolar ridge. The correlation between the BMDQ and LDF was investigated. RESULTS: There was a linear negative correlation between LDF and BMDQ in non-irradiated bone (r = -0.435, P = 0.001) and less pronounced also in irradiated bone (r = -0.309, P = 0.017). In both non-irradiated and irradiated bone, we found distinct differences between the maxilla and mandible with respect to BMDQ. However, a clear difference in mandibular and maxillary vascularity was only seen in non-irradiated bone. CONCLUSION: In non-irradiated bone, LDF and BMDQ were inversely correlated. In irradiated bone, the BMDQ alone is not an adequate preoperative tool for evaluating bone quality because it was not correlated with bone perfusion. PMID:22524288

Abstract in spanish El fibroma osificante periférico (FOP) es una entidad benigna que se incluye en el grupo de las lesiones gingivales reactivas, denominadas con el término genérico de épulis, y se origina, según la teoría más aceptada, en las células del ligamento periodontal. Se manifiesta en forma de tumoración de consistencia firme, bien circunscrita, de color rosado o rojizo y está situada normalmente en la zona incisivo-canina del maxilar superior, siendo rara su aparición (more) en crestas edéntulas. Aparece a cualquier edad, con una mayor incidencia entre la segunda y tercera décadas de la vida, con una ligera predilección por el sexo femenino. Es una lesión de partes blandas, que en ocasiones puede estar asociada a una ligera erosión superficial del hueso subyacente. Se han revisado 3 casos de FOP que afectaban a 2 hombres y 1 mujer de edades comprendidas entre los 39 y los 73 años, presentándose uno de ellos en una cresta alveolar edéntula. En dos casos se observaba radiográficamente una ligera erosión del hueso subyacente y el tercer caso presentaba puntos radioopacos difusos intralesionales. El tratamiento consistió en realizar la exéresis-biopsia de las lesiones, efectuándose dos casos mediante bisturí frío y uno con láser de CO2. Uno de los casos presentó tres episodios de recidiva en el seguimiento postoperatorio. Abstract in english The peripheral ossifying fibroma (POF) is a reactive gingival disorder known under the generic term of epulis and is widely considered to originate from the cells of the periodontal ligament. It manifests as a tumor of firm consistency, well circumscribed, pink or red and is usually located in the incisor-canine area of the maxilla, being uncommon occurrence in edentulous alveolar ridges. Appears without ages difference, with a higher incidence between the second and thir (more) d decades of life, with a slight predilection for females. It is a soft tissue injury, which can sometimes be associated with a slight erosion of the underlying bone surface. We have reviewed 3 cases of POF involving 2 men and 1 woman aged between 39 and 73 years, presenting one of them in edentulous alveolar ridge. In two cases showed radiological slight erosion of the underlying bone and the third case showed diffuse intralesional radiopaque points. Treatment consisted on resection of the lesions and biopsy of them, two cases to be carried out by cold scalpel and a CO2 laser. One case presented three episodes of recurrence in the postoperative follow.

Objectives: Background Intraoral autogenous bone grafts are a convenient source of bone in reconstruction of the residual ridge before dental implant placement. Purpose: The aim of this study was to evaluate bone volume of symphysis donor defects filled with bone substitute compared with unfilled symphysis donor defects. Patients, Materials and Methods: The study included 26 patients who underwent either alveolar ridge reconstruction or maxillary sinus elevation. Two groups were studied: symphyseal donor defects filled with bone substitute and unfilled symphyseal donor defects. Pre- and postoperative volumetric variables were determined using computed tomography scans and the software program SimPlant® (Materialise Dental Italia, Roma, Italy). Results: At 6 months postsurgery, the filled donor defects exhibited a significant increase in bone volume compared with unfilled donor defects (97.7% and 73.4%, respectively). At 18 months postsurgery, volume of unfilled donor defects was reevaluated with no significant increase in bone volume. Conclusions: Six months following block harvesting procedure, filled donor defects maintained bone volume, while unfilled donor sites generated defects that cannot achieve full regeneration; even not 18 months postblock harvesting. PMID:22008097

In the polytocous European brown hare (Lepus europaeus) more than 23% of all successful implantations undergo embryonic resorption. The objective of the study was to establish a minimally invasive ultrasound guided biopsy technique to collect embryonic resorption tissue in vivo. The sampled material was genetically analysed to determine paternity and the sex of the embryo. Female hares were either mated or artificially inseminated and pregnancy was confirmed by ultrasound on day six post ovulation. Subsequent embryonic development was ultrasonographically monitored on a regular basis to detect embryos undergoing resorption. Cell material of the resorption site was collected under ultrasonographic control via transabdominal biopsy of the placenta or aspiration of resorption fluid. To avoid ...

This article reports on a multicenter evaluation of a novel, sterile, antigen-inactivated, mineralized block allograft in humans during a 3-year developmental period. Consecutive partially edentulous patients (n = 73) with severe localized ridge defects (n = 82) were treated with the material. After 4 to 6 months of healing, tapered screw implants were placed in the grafted bone and subsequently restored. Patients were monitored 25 to 36 months after prosthetic restoration. A biopsy was taken of one patient and submitted for histomorphometric analysis. Block allograft survival was 93% at 12 months, and resorption ranged from none (69%) to slight (0 to 2 mm) (31%) for all surviving allografts. Seven block allografts failed and were removed because of improper contouring, prosthesis impingement, and/or infection. The sites were successfully re-treated and restored with dental implants. Soft tissue dehiscence was successfully treated in seven other sites. Implant survival was 99%. One implant failed without allograft failure. It was replaced with a larger-diameter implant, treated with guided bone regeneration, and subsequently restored. Histomorphometric analysis showed rapid incorporation of the allograft at 6 months without inflammation or necrosis. The block allografts were more technique-sensitive than autografts, which necessitated meticulous surgical technique and follow-up. Short-term results for the block allografts indicated a high degree of predictability, but long-term follow-up is needed. PMID:16939013

The present studies were performed to investigate the healing process of the extraction wound in irradiated rats and to clarify the effect of irradiation on bone formation and resorption. 282 Wistar rats of about 100g body weight were used. The region of the left upper molars of experimental rats was exposed to 1000 rad or 2000 rad of /sup 60/Co. On the 7th day after irradiation, the left upper first molar of each rat was extracted. The rats were sacrificed at intervals of from 1 day to 28 days after extraction. Control rats were sacrificed at same intervals after extraction. The maxillary bone including the extraction wound was examined histologically, histometrically, histochemically and ultrastructurally. In irradiated rats, the healing process of extraction wound was disturbed. The osteoblastic new bone formation following production of granulation tissue and periosteal new bone formation was interfered. Histochemical examination revealed that the osteoblasts of irradiated rats reduced enzymatic activity compared with control rats. Ultrastructurally, the cytoplasmic organellae were poorly developed in the osteoblasts of irradiated rats and osteoid formation was reduced. In irradiated rats, the osteoclasts in the interradicular alveolar bone were more numerous and increased more rapidly as compared with control rats, whereas, histometrically, there was no significant difference in the amount of bone loss between control and irradiated rats. Histochemically, there was no distinct difference in the enzymatic activity in osteoclasts between control and irradiated rats. Ultrastructurally, the cytoplasmic organellae and ruffled border were poorly developed in the osteoclasts of irradiated rats. The findings suggest that irradiation induced cytological changes in not only oseoblasts but also osteoclasts and these changes resulted in the delayed healing of extraction wound.

The objective of this study was to evaluate the use of bioactive glass foams produced by the sol-gel process, associated or not with platelet-rich plasma (PRP), in the regeneration of bone defects. Mongrel dogs (n = 14) were divided into two groups after having their superior first premolar removed. A small piece of vestibular bone from the alveolus was intentionally removed. The area was filled with bioactive glass foam produced by the sol-gel method. Two groups were tested: group A was the glass foam; group B was the same material associated with PRP, prepared from each animal. The other side of alveolar bone was used as a control group, in which the bone defect did not receive any biomaterial. The thickness of the bone area was measured before and after the intervention. After a period of 60 days implantation, the right and left bones were measured again, and a bone biopsy on both regions was conducted for histological analysis. The findings show an increase of bone thickness for both materials implanted compared to the control group. Group B, implanted with bioactive glass foam associated with PRP, showed a thicker bone area compared to Group A. Histological results indicate bone formation for both materials used. However, the bioactive glass associated with PRP gave rise to a more mature bone formation. These results show that bioactive glass foams processed by a sol-gel method is effective in maintaining the thickness of the alveolar ridge, and the use of PRP associated with the foams improve bone formation. PMID:18493909

OBJECTIVE: Excessive pressure due to wearing mal-adapting dentures is well known to cause residual bone resorption beneath the denture. X-rays have been commonly utilized to evaluate the changes in the bone beneath the denture. However, X-ray images merely detect bone density and relatively large changes in the bone shape and structure, whereas nuclear medicine imaging can detect functional changes, which occur prior to structural changes. This article aimed to describe the time course of the bone metabolism at the residual ridge beneath the denture following denture use by (18)F-fluoride positron emission computerized-tomography (PET)/computed tomography (CT) scanning. METHODS: Three subjects, who had a free-end edentulous mandible, were treated with a denture replacing the edentulous region of the dental arch. The metabolic changes in the residual bone beneath the denture were assessed by (18)F-fluoride PET/CT imaging. (18)F-fluoride PET/CT scanning was performed at baseline, and 4-6 and 13 weeks after denture use. A volume of interest (VOI) was placed on their mandibles at the edentulous region beneath the denture on the PET/CT image. CT value and mean standardized uptake value (SUV) of the VOI were calculated. The difference in the time variation between the CT value and SUV was analyzed. RESULTS: The adaptation of the denture base to the residual ridge was successful, and there was no trouble such as pain at the residual ridge beneath the denture. The SUVs of each VOI significantly increased at 4-6 weeks after denture use and then decreased at 13 weeks in all three subjects (P VOI remained static after denture use in all three subjects. CONCLUSIONS: This study indicates that in the present first-time removable partial denture (RPD) users, wearing of a well-adapted RPD initially increased bone metabolism beneath the denture and then decreased it at around 13 weeks after RPD use without any bone structural changes detectable by clinical X-rays. These metabolic changes are a mechanobiological reaction to the pressure induced by RPD use. PMID:22903818

BACKGROUND: The transcrestal approach with osteotomes is a commonly applied and predictable technique for maxillary sinus floor elevation. However, Schneiderian membrane perforation is a common and often inevitable intraoperative complication. Recently, the use of balloons has been proposed to reduce the risk of sinus membrane perforation and to facilitate the surgical technique. The aim of this study was to determine membrane elevation height and perforation rate using the transcrestal balloon technique (B) and a conventional osteotome approach, as control (C). METHODS: Ten fresh, completely edentulous cadaver heads (seven male and three female) were selected. In a split-mouth design, each sinus was randomly assigned to either the experimental or the control technique. Pre-surgical planning was aided by cone-beam computed tomography. During the procedure, an endoscope was used to monitor the elevation procedure and the occurrence of sinus perforation. The elevation continued until either 15 mm (measured from the alveolar crest) was reached or a perforation occurred. The residual ridge and the elevated membrane height were measured and compared with the paired Student's t-test. Presence of sinus perforation was recorded at three cutoff points: 10, 12, and 15 mm. RESULTS: The mean age of the specimens was 77.7 ± 14.2 years (range 49-92). The mean initial, final, and elevated sinus membrane height for the B group was 5.3 ± 1.9, 13.7 ± 1.9, and 8.3 ± 3.1 mm, whereas the correspondent values for the C group were 5.1 ± 2.1, 13.2 ± 2.8, and 8.1 ± 3.1 mm. The incidence of sinus perforation, using 10, 12, and 15 mm as end points was 0%, 22.2%, and 44.4% in the B group, whereas in the C group the respective values were 10.0%, 20.0%, and 50.0%. No statistically significant differences were found between the two groups for all the above-mentioned variables. In addition, mean residual ridge height was not significantly different between the non-perforation and perforation sites in the B group (5.2 ± 2.2 and 5.5 ± 1.7 mm) and in the C group (5.2 ± 2.5 and 5.0 ± 2.0 mm). Three cadavers had perforations in both sinuses, accounting for 66.6% of total number of perforations. CONCLUSIONS: Based on the findings of this study, the balloon and the conventional osteotome approach are comparable in terms of perforation rate as it relates to the elevation height. Also, the amount of residual alveolar bone was not related to the incidence of perforation and the height of sinus elevation. PMID:22725990

Abstract in spanish Propósito: La periodontitis crónica es una enfermedad de naturaleza inflamatoria y etiología infecciosa, caracterizada por la destrucción del aparato de inserción del diente, cemento radicular, ligamento periodontal y hueso alveolar, y que causa la pérdida de los dientes. Durante su desarrollo se establece un denso infiltrado inflamatorio celular, constituido principalmente por linfocitos T, con la capacidad de secretar una serie de citoquinas que participan en los (more) eventos patogénicos de la enfermedad, regulando la inflamación de los tejidos periodontales y la destrucción del hueso alveolar. En la artritis reumatoide, la citoquina recientemente identificada RANKL (Ligando del receptor activador del factor nuclear kB) es expresada por los linfocitos T CD4+, participando directamente en los procesos de estimulación de la diferenciación osteoclástica y en la activación de osteoclastos maduros, y por lo tanto, en la destrucción ósea articular. El objetivo del presente estudio es determinar si mayores niveles de RANKL se encuentran asociados a la periodontitis crónica y si estos son sintetizados por los linfocitos T CD4+ reclutados en los sitios con periodontitis crónica. Material y métodos: En 33 pacientes mayores de 35 años de edad afectados de periodontitis crónica y 20 individuos controles sanos, se determinaron los niveles de mensajero de ácido desoxiribonucleico (mARN) de RANKL en biopsias de encía mediante transcriptasa reversareacción en cadena de la polimerasa (RT-PCR) en tiempo real. A partir de las mismas biopsias, células gingivales totales fueron aisladas para inmunotipificar y cuantificar los leucocitos infiltrantes gingivales e identificar las células responsables de la expresión de RANKL mediante doble tinción por citometría de flujo. Resultados: Los pacientes con periodontitis mostraron mayores niveles de mARN de RANKL en comparación a individuos sanos, observándose que la expresión de RANKL se incrementó en 238,3 veces con relación a los sujetos controles. Los individuos con periodontitis mostraron mayores porcentajes de linfocitos T CD4+ y CD8+. Además, una asociación entre RANKL y los linfocitos T CD4+ fue determinada mediante doble tinción por citometría de flujo. Conclusión: Estos datos demuestran que mayores niveles de RANKL se encuentran asociados a la periodontitis y que estos mayores niveles se pueden explicar en parte a la actividad de los linfocitos T CD4+ en el sitio de la infección. La determinación de la asociación entre la periodontitis crónica y la síntesis de RANKL constituye un interesante mecanismo molecular que contribuye a explicar en parte la destrucción tisular asociada y permite proyectar posibles nuevas estrategias inmunoterapéuticas que ayudarían a controlar la pérdida de tejido característica de la enfermedad periodontal. Abstract in english Background: Chronic periodontitis is an infectious disease, characterized by alveolar bone destruction and teeth loss. Receptor activator of nuclear factor kB- ligand (RANKL) is an osteoclastogenic cytokine, central regulatory factor in the osteoclasts life-span and physiological and pathological bone resorption. Gingival T cells synthesize RANKL contributing to molecular local unbalance that entail to the alveolar bone resorption seen in periodontitis. Our study was aime (more) d at associating the levels of RANKL with the CD4+ T cell activity present in gingival tissues of chronic periodontitis patients. Methods: Gingival biopsies were obtained from 33 chronic periodontitis patients and 20 healthy controls. Specimens were either formalin fixed and paraffin embedded for real-time reverse transcriptionpolymerase chain reaction (RT-PCR) and histological analysis, or tissue digestion processed for cell culture and flow cytometry analysis. RANKL mRNA and protein levels were determined by quantitative RT-PCR and enzyme-linked immunosorbent assay (ELISA) in gingival cells culture supernatants. Gingival leukocytes were quantified by flow cytometry. RANKL and CD4 immunoreactivity was analyzed by flow cytometry and confocal microscopy. Results: RANKL mRNA levels were higher in periodontitis than in healthy subjects and spontaneous and LPSand PHA-stimulated RANKL synthesis were higher also in patients than controls. CD4+ T lymphocytes were the predominant infiltrate cell subset present in gingival tissues of periodontitis patients. Furthermore, an association between RANKL and CD4+ T cells was determined by double-staining flow cytometry and confocal microscopy. Conclusion: Taken together, these data demonstrate that gingival CD4+ T cells are the main cells responsible for the higher levels of RANKL observed in chronic periodontitis human patients.

Osteoporosis is an important age-related bone disease characterized by increased bone turnover with insufficient bone formation relative to bone resorption. According to the current understanding of this disorder, anti-resorptive and anabolic drugs have been developed for therapeutic intervention. Another therapeutic approach consists of dissociating bone resorption and formation. Preclinical and clinical studies provided evidence that strontium (in the form of ranelate) induces beneficial effects on bone mass and resistance in animal models of bone loss and in osteoporotic patients. These effects are mediated in part by the pharmacological actions of strontium on bone metabolism, by reducing bone resorption and maintaining or increasing bone formation. Current pharmacological studies show...

Alveolar breath sampling and analysis can be extremely useful in exposure assessment studies involving volatile organic compounds (VOCs). Over recent years scientists from the EPA's National Exposure Research Laboratory have developed and refined an alveolar breath collection ...

We report a 37 year old Chinese woman with systemic lupus erythematosus complicated by concomitant cytomegalovirus pneumonia and alveolar haemorrhage. The cytomegalovirus pneumonia may have been causally related to the alveolar haemorrhage.

... lip and chin. This nerve is called the inferior alveolar nerve. Any infections, tumors or bone disease that may ... problem. It is caused by injury to the inferior alveolar nerve in your lower jaw. Complete healing may take ...

ABSTRACT. Maxillary defects resulting from cancer, trauma, and congenital malformation affect the chewing efficiency and retention of dentures in these patients. The use of implant-retained palatal obturator dentures has improved the self-esteem and quality of life of several subjects. We evaluate the stress distribution of implant-retained palatal obturator dentures with different attachment systems by using the photoelastic analysis images. Two photoelastic models of the maxilla with oral-sinus-nasal communication were fabricated. One model received three implants on the left side of the alveolar ridge (incisive, canine, and first molar regions) and the other did not receive implants. Afterwards, a conventional palatal obturator denture (control) and two implant-retained palatal obturator dentures with different attachment systems (O-ring; bar-clip) were constructed. Models were placed in a circular polariscope and a 100-N axial load was applied in three different regions (incisive, canine, and first molar regions) by using a universal testing machine. The results were photographed and analyzed qualitatively using a software (Adobe Photoshop). The bar-clip system exhibited the highest stress concentration followed by the O-ring system and conventional denture (control). Images generated by the photoelastic method help in the oral rehabilitator planning. PMID:23143194

The purpose of this research was to evaluate the maximum stress around osseointegrated implants and alveolar ridge, in a mandible with left partial resection through a photoelastic mandibular model. The first group consisted of two implants: traditional model (T), implants placed in the position of both canines; fulcrum model (F), implants placed in the position of left canine CL and right lateral incisor LiR. Both models linked through a bar and clips. The second group was consisted of three implants, with implants placed in the position of both canines (CR and CL) and the right lateral incisor (LiR), which composed four groups: (1) model with 3 "O" rings, (2) model 2 ERAs, bar with clips, (3) model 2 ERAs bar without clips; (4) model "O" ring bar and ERA. An axial and an oblique load of 6.8 kgf was applied on a overdenture at the 1st Pm, 2nd Pm, and 1st M. Results showed that the area around the left canine (CL) was practically free of stress; the left lateral incisor (LiL) developed only small tensions, and low stress in all the other cases; the right canine tooth suffered the largest concentrations of stress, mainly with the ERA retention mechanism. PMID:20467562

Abstract in english Many techniques have been proposed for root coverage. However, none of them presents predictable results in deep and wide recessions. OBJECTIVES: The aim of this case series report is to describe an alternative technique for root coverage at sites showing deep recessions and attachment loss >4 mm at buccal sites. MATERIAL AND METHODS: Four patients presenting deep recession defects at buccal sites (>4 mm) were treated by the newly forming bone graft technique, which consi (more) sts in the creation of an alveolar socket at edentulous ridge and transferring of granulation tissue present in this socket to the recession defect after 21 days. Clinical periodontal parameters, including recession depth (RD), probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), plaque index (PI) and keratinized gingiva width (KGW) were evaluated by a single examiner immediately before surgery and at 1, 3, 6 and 9 months postoperatively. RESULTS: All cases showed reduction in RD and PD, along with CAL gain, although no increase in KGW could be observed. These findings suggest that the technique could favor periodontal regeneration along with root coverage, especially in areas showing deep recessions and attachment loss.

Abstract Objective: To determine the incidence and most frequent anatomical locations of residual oronasal fistulas in children with different types of clefts who were treated at the University Department of Maxillofacial and Oral Surgery in Ljubljana. Design: Retrospective analysis of 857 consecutive cleft patients born between 1984 and 2003. Results: After primary surgical repair, 33 out of 857 (3.9%) children had residual oronasal fistulas. The incidence of clinically significant fistulas that required surgical repair was 17 of 857 (2.0%). In UCLP, BCLP and CP children, the incidence of palatal fistulas was 23 of 644 (3.6%), while those with clinically significant palatal fistulas was 12 of 644 (1.9%). Oronasal fistulas were most frequently found in children with BCLP or 9 of 88 (10.2%), followed by UCLP or 12 of 215 (5.6%) and CP children at 12 of 341 (3.5%). No fistulas were found in CL±A children. In 10 cases (30.3%), the oronasal fistula remained in the alveolar ridge, in 11 cases (33.3%) in the anterior part of the hard palate, and in 11 cases (33.3%) at the junction of the hard and soft palates. In one case (3%), the records were lost. Conclusion: The low incidence of oronasal fistulas is the result of a surgical technique and tensionless suturing, followed by a two-layer closure, two-stage palate repair in BCLP and UCLP patients and preoperative orthopedics in UCLP cases. Keywords : oronasal fistula, palatal fistula, cleft palate. PMID:21740163

Fifty-seven treatments were performed on 27 head and neck patients with recurrent or residual tumors on a high dose rate, remote controlled afterloading unit: There were 16 cases of maxillary sinus tumors, 6 epipharynx, 3 alveolar ridge, 1 hard palate and 1 floor of mouth. All patients have been followed up more than 2 years except one. Five patients are alive without local recurrence for more than 2 years. In 13 patients local tumors disappeared once and normal mucosa covered the tumor sites. Two patients died from local bleeding. In six patients this method failed to destroy tumors. Our purpose was palliative local control: therefore, in two-thirds of cases treated we were successful with this easy method of nonfractionated acute intracavitary radiation. This result is favorable, considering that all cases treated here were failures following full dose external radiation, although the treatment had to be repeated more than twice in 15 cases. Relief of symptoms is excellent when this therapy is used.

ABSTRACT:: Extranodal natural killer (NK)/T-cell lymphoma, nasal type, is a rare type of non-Hodgkin's lymphoma with similar presentation to various benign inflammatory diseases. Adequate biopsy is required for a diagnosis because this lymphoma frequently coexists with large amount of necrosis and inflammation. In this study, a case of a 49-year-old woman presenting with a 3-week history of right maxillary alveolar ridge pain with a subsequent diagnosis of periodontitis is described. The patient's clinical condition deteriorated over a period of 6 weeks. Computed tomography delineated involvement of the right maxillary sinus, posterior part of the right pharynx and right nasal cavity. Immunohistopathology initially revealed Wegener's granulomatosis, followed by extranodal nasal-type NK/T-cell lymphoma. Severe refractory periodontitis in a background of Wegener's granulomatosis may be the initial presentation of extranodal NK/T-cell lymphoma, nasal type. In addition to careful examination, radiographic and laboratory testing, multiple large biopsies should be taken for immunohistochemical analysis to obtain an appropriate diagnosis. PMID:23111392

The purpose of the present study was to evaluate stress distribution by finite element analysis in an accurate model simulating trabecular bone using micro-CT. Dentulous and edentulous maxillary jaws of Japanese adult cadavers were used (5 sides each; total, 10 sides). Imaging was performed using a micro-CT, followed by reconstruction with 3-D images. Finite element analysis models were developed using the maxilla with average bone morphometry. A load corresponding to occlusal force was applied in different loading conditions, followed by evaluation of stress distribution. In dentulous maxillas, a load was applied in the dental axis direction to the first molar crown (LD). In edentulous maxillas, a load was applied directly to a circular area 4mm in diameter (LER0) to a cylinder 4mm in diameter and 10mm in height (LER10) corresponding to the first molar area. Stress was concentrated in cortical bone around the first molar, trabecular bone and cortical bone at the maxillary sinus base in LD, cortical bone of the alveolar ridge in LER0, and trabecular bone around the cylinder and cortical bone at the maxillary sinus base in LER10. LER0 showed a stress distribution markedly different from that in LD. Compared with LER0, LER10 showed a stress distribution close to that in LD. A model simulating trabecular bone allows a more accurate evaluation of stress distribution.   

Rhabdomyosarcoma has 2 major histological subtypes, embryonal and alveolar. Alveolar histology is associated with the fusion genes PAX3-FKHR and PAX7-FKHR. Definition of alveolar has been complicated by changes in terminology and subjectivity. It is currently unclear whether adverse clinical behavio...

The number of fibroblasts composing the alveolar structures in controlled within narrow limits by a strictly modulated rate of fibroblast replication. One possible source of growth-modulating signals for alveolar fibroblasts is the alveolar macrophage, a member of the mononuclear phagocyte family of...

Wiskott Aldrich Syndrome protein (WASP) has a unique regulatory role in sealing ring formation and bone resorption in osteoclasts. Here, using the TAT-transduction method, we show the possible role of WASP domain(s) in sealing ring formation and bone resorption. Transduction of TAT-fused full-length...

Allografts are often used during revision hip replacement surgery for stabilization of the implant. Resorption of the allograft may exceed new bone formation, and instability of the prosthesis can develop. We investigated whether strontium could regulate the imbalance of fast resorption of allograft and slower formation of new bone, because it is both an anabolic and an anticatabolic agent.

Background Receptor activator of nuclear factor kappa B (NF-kB) ligand (RANKL) and osteoprotegerin (OPG) have been recently shown to play important roles in bone resorption. The aim of this study was to investigate the possible association between the expression of bone resorption regulators (RANKL ...

Active ridge propagation frequently occurs along spreading ridges and profoundly affects ridge crest segmentation over time. The mechanisms controlling ridge propagation, however, are poorly understood. At the slow spreading Mid-Atlantic Ridge at 21.5°N a seismic refraction and wide-angle reflection...

  Rat fetuin, which is the rat counterpart of human ?2-HS glycoprotein and bovine fetuin, is only detectable in calcified tissues such as bone matrices and dentin, and bone cells such as osteoblasts and osteocytes immunohistochemically. The effect of this protein on bone resorption was examined to study its physiological role in bone metabolism. Rat fetuin increased bone resorption in the presence of low concentrations of parathyroid hormone (PTH), but it had no activity on bone resorption without PTH. The increase in bone resorption by PTH and PTH plus rat fetuin was inhibited by the addition of chymostatin, an inhibitor for cathepsin L. Moreover, we found that when type I collagen from rat was preincubated with rat fetuin, the digestion of rat type I collagen by cathepsin L was increased. These findings suggest that rat fetuin present in bone matrix is important in bone resorption.   

The hypothesis of this study is that children with unexpected early apical resorption of the primary teeth are also predisposed to resorption in the permanent dentition. Accordingly, the aim was to perform a longitudinal study focussing on the permanent teeth in children with unexpected early apical resorption in the primary dentition.Panoramic radiographs of 12 children (7 boys and 5 girls) aged 6 years 4 months to 8 years 9 months with unexpected early apical resorption of primary teeth were identified from a dental archive of 588 patients. After written request, follow-up radiographs were obtained (2-15 year interval between early and follow-up radiographs). The radiographs were examined in order to verify the abnormal resorption pattern of the primary teeth and dental deviations in the...

Prostate carcinoma frequently metastasizes to bone where the microenvironment facilitates its growth. Inhibition of bone resorption is effective in reducing tumor burden and bone destruction in prostate cancer. However, whether drugs that inhibit osteoclast function inhibit tumor growth independent of inhibition of bone resorption is unclear. Calcium is released during bone resorption and the calcium sensing receptor is an important regulator of cancer cell proliferation. The goal of this investigation was to elucidate the role of calcium released during bone resorption and to determine the impact of drugs which suppress bone resorption on tumor growth in bone. To compare tumor growth in a skeletal versus non-skeletal site, equal numbers of canine prostate cancer cells expressing luciferas...

Abstract in spanish El granuloma periférico de células gigantes (GPCG) es una lesión reactiva benigna relativamente frecuente de la cavidad bucal. Se origina a partir del periostio o de la membrana periodontal tras una irritación o un traumatismo crónico que actúa localmente. Se manifiesta en forma de nódulo de color rojo-púrpura, situado en la encía o en el reborde alveolar edéntulo, preferentemente en la mandíbula. Aparece a cualquier edad, con una mayor incidencia entre la quin (more) ta y sexta décadas de la vida, con una ligera predilección por el sexo femenino. Es una lesión de las partes blandas que muy rara vez implica el hueso subyacente, aunque puede causarle una erosión superficial. Se han revisado cinco casos de GPCG que afectaban a 3 hombres y a 2 mujeres de edades comprendidas entre los 19 y 66 años, presentándose tres de ellos en el maxilar superior. En dos casos se observaba radiográficamente una reabsorción ósea en forma de "aplanamiento". El tratamiento consistió en realizar la exéresis-biopsia, efectuándose dos casos mediante láser de CO2 y tres con bisturí frío. No se ha observado ninguna recidiva en el seguimiento postoperatorio (rango de 10 meses a 4 años). En el diagnóstico diferencial se deben descartar lesiones de características clínicas e histológicas muy similares -como el granuloma central de células gigantes-, que asientan en el interior del propio maxilar y cuyo comportamiento es más agresivo; solamente el estudio radiológico permitirá esta distinción. El diagnóstico precoz y preciso de esta lesión permite efectuar un tratamiento conservador sin riesgo para los dientes vecinos ni para el hueso adyacente. Abstract in english Peripheral giant cell granuloma (PGCG) is a relatively frequent benign reactive lesion of the oral cavity, originating from the periosteum or periodontal membrane following local irritation or chronic trauma. PGCG manifests as a red-purple nodule located in the region of the gums or edentulous alveolar margins, fundamentally in the lower jaw. The lesion can develop at any age, though it is more common between the fifth and sixth decades of life, and shows a slight female (more) predilection. PGCG is a soft tissue lesion that very rarely affects the underlying bone, though the latter may suffer superficial erosion. The present study reviews 5 cases of PGCG, involving 3 males and 2 females between 19-66 years of age, and with presentation in the upper jaw in three cases. Two patients showed radiological concave depression images corresponding to bone resorption. Treatment consisted of resection and biopsy, using a carbon dioxide laser in 2 cases and a cold scalpel in the remaining 3. There were no relapses during postoperative follow-up (range 10 months to 4 years). The differential diagnosis of PGCG includes lesions with very similar clinical and histological characteristics, such as central giant cell granuloma, which are located within the jaw itself and exhibit a more aggressive behavior. Only radiological evaluation can establish a distinction. The early and precise diagnosis of these lesions allows conservative management without risk to the adjacent teeth or bone.

Abstract in spanish Se han propuesto diferentes procedimientos quirúrgicos para la preservación y aumento del reborde alveolar, así como para el tratamiento de recesiones gingivales e incremento de la amplitud de la encía adherida, alrededor de dientes naturales e implantes. Cuando se utilizan injertos autógenos en estas intervenciones se evidencian algunas desventajas que incluyen la inconformidad asociada con un sitio quirúrgico adicional y la disponibilidad limitada de tejido donant (more) e. Recientemente, se utilizan como sustitutos de los injertos autógenos en cirugía periodontal, dos tipos de aloinjertos de matriz dérmica acelular. Debido al gran uso de matrices alodérmicas, no solo en periodoncia sino en otras áreas de las ciencias de la salud, se ha dispuesto mayor atención a las medidas de seguridad y a la eficacia de varios procesos de esterilización realizados por los bancos tisulares. Desafortunadamente, el procesamiento y las técnicas de esterilización podrían producir efectos deletéreos sobre las propiedades biomecánicas de los tejidos alogénicos, ocasionando resultados indeseables en las intervenciones realizadas. Por otra parte, se ha indicado que a pesar de la rigurosidad de los procesos de evaluación en donantes y tejidos, además del procesamiento extenso de las matrices, existe la posibilidad de permanencia de material genético en los aloinjertos disponibles comercialmente. Abstract in english Several surgical procedures have been proposed for the preservation and increase of the alveolar ridge, and for the treatment of gingival recessions and to increase the width of attached gingiva around natural teeth or implants. The disadvantages of harvesting autogenous grafts on these procedures lie in the postoperative discomfort associated with an extra surgical site, as well as the limitation of available donor tissue. Recently, two types of acellular dermal matrix a (more) llografts have been approved as substitutes for autogenous grafts in mucogingival surgery. Due to the increased use of allografts on periodontics and other areas of health sciences, has brought more focus to the safety of allogenic tissue and the efficacy of various sterilization techniques. Unfortunately, these sterilization techniques could produce deleterious effects on the biomechanical properties of allogenic tissues, causing undesirable results on the interventions. Moreover, it has been suggested that despite the thoroughness of the evaluation processes and tissue donors, in addition to the processing of the matrices, there is possibility of retention of genetic material on allografts commercially available

Osteoporosis is a systemic disease in which the skeletal condition is characterized by a decreased mass of normally mineralized bone, due to an augmentation of bone resorption processes. Bone biomarkers serum are used for the diagnosis. On the other hand the main cause of the resorption in the bone jaws are periodontitis, inflammatory cysts, developmental cysts, odontogenic neoplasms. Periodontal diseases can be localized to a single site of the jaws or can affect all the teeth, with a massive bone resorption. The cysts are classified in developmental and inflammatory. They caused a local bone resorption in the jaws. Keratocystic odontogenic tumor produces a large bone resorption for its local aggressive nature. Their diagnosis is clinical and radiological.The aim of our review is to find a correlation between bone biomarkers serum and periodontitis, inflammatory cists, developmental cysts, odontogenetic neoplasms.The RANK/RANKL/OPG system is the most studied not only in osteoporosis but also in the periodontitis, inflammatory cysts, developmental cysts, odontogenic neoplasms. In the last years osteoimmunology was used to study the periodontal disease progression, because the immunity cells start the bone resorption processes.A lot of studies analyze the biomarkers present in the biofluids, as saliva and gingival crevicular fluid, but not the correlation with serum biomarkers.Future studies must be organized to deepen the correlation between bone biomarkers and bone jaws resorption and to allow diagnosis and prognosis of periodontitis, inflammatory cysts, developmental cysts, odontogenic neoplasms. PMID:23087720

Summary Osteoporosis is a systemic disease in which the skeletal condition is characterized by a decreased mass of normally mineralized bone, due to an augmentation of bone resorption processes. Bone biomarkers serum are used for the diagnosis. On the other hand the main cause of the resorption in the bone jaws are periodontitis, inflammatory cysts, developmental cysts, odontogenic neoplasms. Periodontal diseases can be localized to a single site of the jaws or can affect all the teeth, with a massive bone resorption. The cysts are classified in developmental and inflammatory. They caused a local bone resorption in the jaws. Keratocystic odontogenic tumor produces a large bone resorption for its local aggressive nature. Their diagnosis is clinical and radiological. The aim of our review is to find a correlation between bone biomarkers serum and periodontitis, inflammatory cists, developmental cysts, odontogenetic neoplasms. The RANK/RANKL/OPG system is the most studied not only in osteoporosis but also in the periodontitis, inflammatory cysts, developmental cysts, odontogenic neoplasms. In the last years osteoimmunology was used to study the periodontal disease progression, because the immunity cells start the bone resorption processes. A lot of studies analyze the biomarkers present in the biofluids, as saliva and gingival crevicular fluid, but not the correlation with serum biomarkers. Future studies must be organized to deepen the correlation between bone biomarkers and bone jaws resorption and to allow diagnosis and prognosis of periodontitis, inflammatory cysts, developmental cysts, odontogenic neoplasms. PMID:19455299

Subperiosteal resorption in finger phalanges is usually thought to be the result of osteoclastic bone resorption on the periosteal surface of bone, progressive centripetally with creation of the serrated appearances and ''lace-like'' patterns in periosteal cortical bone. Our longitudinal microradioscopic observations in patients with secondary hyperparathyroidism of chronic renal failure have revealed evidence of another pathogenetic mechanism: by the enlargement of intracortical juxtaperiosteal resorption spaces, the remaining thin layer of bone is broken down from inside the bone, i.e., a centrifugal rather then centripetal process.

Abstract in portuguese OBJETIVO: Determinar a acurácia de diferentes métodos radiográficos para estimação de altura óssea na região do forame mentual. METODOLOGIA: Vinte hemi-mandíbulas humanas, secas, foram examinadas por radiografia periapical e panorâmica e tomografia computadorizada. Um paquímetro digital foi usado para medir os traçados obtidos das radiografias em três diferentes tempos (grupos A1, A2 e A3) e nas hemi-mandíbulas seccionadas transversalmente (grupo B). As medi? (more) ?ões foram: Medida 1 - do limite superior da crista óssea ao limite superior do forame mentual; Medida 2 - do limite superior do forame mentual ao limite inferior do osso cortical da base da mandíbula; Medida 3 - do limite superior da crista óssea ao limite inferior do osso cortical da base da mandíbula. Os dados foram analisados por teste t de Student e teste de Friedman. RESULTADOS: Os valores médios de diferença na Medida 1 foram 0,33 mm, 0,35 mm e 0,85 mm para a radiografia periapical, tomografia computadorizada e radiografia panorâmica, respectivamente (intervalos de confiança de 0,17 a 0,49 mm, 0,18 a 0,53 mm e 0,38 a 1,32 mm, respectivamente). As radiografias panorâmicas mostraram as maiores diferenças nas Medidas 2 e 3, com valores médios de 1,05 mm e 1,93 mm, respectivamente. CONCLUSÃO: A radiografia periapical e a tomografia computadorizada mostraram a melhor acurácia. Sugere-se uma margem de segurança em caso de cirurgias. Abstract in english PURPOSE: To determine the accuracy of different radiographic methods for bone height estimation at the mental foramen area. METHODS: Twenty dry human hemimandibles were examed by using periapical and panoramic radiography, and computed tomography. An electronic digital caliper was used to measure the tracings obtained from the radiographies in three different times (groups A1, A2 and A3) and in the cross-sectioned hemimandibles (group B). Measurements consisted of: Measur (more) e 1 - from the upper limit of the alveolar ridge to the upper limit of the mental foramen; Measure 2 - from the upper limit of the mental foramen to the inferior limit of the cortical bone of the base of the jaw; Measure 3 - from the upper limit of the alveolar ridge to the inferior limit of the cortical bone of the base of the jaw. Data were analyzed with Student-t and Friedman tests. RESULTS: The average difference values in Measure 1 were 0.33 mm, 0.35 mm and 0.85 mm for the periapical radiography, computed tomography and panoramic radiography, respectively (confidence intervals of 0.17 mm to 0.49 mm, 0.18 mm to 0.53 mm and 0.38 mm to 1.32 mm, respectively). Panoramic radiographies showed the greatest differences in Measures 2 and 3, with average values of 1.05 mm and 1.93 mm, respectively. CONCLUSION: Periapical radiography and computed tomography showed the best accuracy. A safety margin for surgical purposes has been suggested.

INTRODUCTION: Ossifying fibroma (OF) is a well-defined benign neoplasm characterized by slow growth and predilection for the posterior mandible site, usually treated by conservative surgical approaches. In this context, Le Fort I Approach (LFIA) has been increasingly used providing good visualization and an easy access to the lesion. It also allows removal of the lesion quickly. Although there are case reports using LFIA for the management of benign neoplasms, odontogenic cysts and tumors of the middle third of face, to our knowledge, only one article describes the use of surgical LFIA for OF of the maxilla. Thus, the objective of this study was to report the second paper on the use of horizontal osteotomy of the maxilla in the resection of an extensive OF and conduct a brief literature review on this surgical approach. CASE REPORT: The following case report describes a 33-year-old man who was diagnosed with OF. Oral examination showed a painless swelling of hard consistency, covered by normal mucosa in edentulous alveolar ridge of the maxillary posterior region of the right side. Tomographic slices revealed that the image with mixed density had a centrifugal growth, with expansion of the buccal and lingual cortical with an upper displacement of the maxillary sinus. The patient was admitted to the hospital for surgical resection of the lesion via LFIA. Satisfactory functional results were obtained after 18-month follow-up period. In addition, no recurrence or clinical complaints were noted. DISCUSSION: LFIA shall be considered as a feasible option when planning surgery for removal of extensive benign lesions located in midfacial region because it is a predictable technique and routinely performed by the oral and maxillo-facial surgeons. PMID:22933036

The purpose of this study was to investigate by CT the origin of radiodense maxillary sinus concretions and whether CT densitometry is effective in the prediction of maxillary sinus aspergillosis and in the differentiation of the origin of these concretions. In a prospective study in 21 patients with radiodense maxillary sinus concretions detected by radiography, a preoperative CT study of the paranasal sinuses and the concretions was undertaken. Additional scans of the upper alveolar ridge were also performed. Radiological findings were compared with clinical symptoms and with CT findings, especially CT densitometry of the sinus concretions and dental root-filling material. All patients underwent a functional Caldwell-Luc operation; histological and microbiological examinations were performed. Fifteen of the 21 patients (71.4%) with radiodense concretions had a histological and microbiological diagnosis of sinus aspergillosis. The sinus concretions had CT densities higher than 2000 HU (Housfield units) in 15 patients and lower than 2000 HU in 6. Fourteen of 15 patients (93.3%) with concretions ahving CT densities higher than 2000 HU had a postoperative diagnosis of maxillary sinus aspergillosis. The mean CT density of the sinus concretions in patients with maxillary sinus aspergillosis was 2868 HU (range 1870-3070 HU), and in patients without aspergiollosis was 778 HU (range 228-2644 HU). The mean CT density of the dental root-filling material was 2866 HU (range 2156-3070 HU). Paranasal sinus CT with CT densitometry of a sinus concretion has a higher accuracy than standard radiogrpahy and clinical findings in the prediction of maxillary sinus aspergillosis (93.3% vs 71.4%). CT densitometry helps to confirm the dental origin of maxillary sinus concretions and to explain a possible dental pathogenesis of maxillary sinus aspergillosis. (orig.)

Purpose: The purpose of this longitudinal study was to evaluate the success of bovine bone and calcium sulfate (CaSO(4) ) as sinus augmentation material with osteotome maxillary sinus lift. Materials and Methods: Thirty-one osteotome sinus lift procedures were performed for 18 healthy patients (7 males and 11 females). A mixture of bovine bone and CaSO(4) (ratio, 4:1) was used as sinus augmentation material with simultaneous implant placement. Implants were loaded 4 to 5?months postimplant surgery. Cases were followed for an average of 23.4?months postloading (range, 12-60?months). Results: The mean age of the study group was 49.7?±?10.66?years. The residual height of the alveolar ridge ranged from 5.5 to 11?mm (mean, 8.16?±?1.52?mm). Four to 5?months after implant placement, the x-ray showed a 1.5 to 5?mm apical shift of the sinus floor (mean, 3.47?±?0.97?mm), which was maintained to the end of the evaluation period. At 12?months postloading, crestal bone loss ranged from 0.5 to 1.5?mm (mean, 0.87?±?0.26?mm), and pocket depth ranged from 2 to 4?mm (mean, 2.9?±?0.67?mm). No significant change in crestal bone loss or pocket depth was noticed afterward. Conclusion: Bovine bone plus CaSO(4) can be used successfully as a sinus augmentation material with osteotome sinus elevation. The use of CaSO(4) significantly improved the handling properties of bovine bone and helped to stabilize the bone graft particles during healing. PMID:22176672

IntroductionCone-beam computed tomography (CBCT) has been used to assess alveolar bone changes after rapid palatal expansion. The purpose of this study was to investigate the accuracy of alveolar bone-height measurements from CBCT images with varied bone thicknesses and imaging resolutions. MethodsEleven maxillary specimens from 6-month-old pigs were measured for alveolar bone height (distance between drilled reference holes and alveolar crests) at 6 locations with a digital caliper, followed by CBCT scanning at 0.4-mm and 0.25-mm voxel sizes. Buccal alveolar bone of these locations was then reduced approximately by 0.5 to 1.5 mm, followed by CBCT rescanning with the same voxel sizes. The CBCT images were measured by using 3-dimensional software to determine alveolar bone height and thickn...

The aim was to explore the relation between radiographic bone quality on panoramic radiographs and relative alveolar bone level. Digital panoramic radiographs of 94 female patients were analysed (mean age, 44.5; range, 35?74). Radiographic density of the alveolar bone in the premolar region was determined using Agfa Musica? software. Alveolar bone level and bone quality index (BQI) were also assessed. Relationships between bone density and BQI on one hand and the relative loss of alveolar bone level on the other were assessed. Mandibular bone density and loss of alveolar bone level were weakly but significantly negatively correlated for the lower premolar area (r?=?-.27). The BQI did not show a statistically significant relation to alveolar bone level. Radiographic mandibular bone density ...

Evaluate the efficacy of new integrated resistance and aerobic training .... Monitoring Bone Health by Daily Load Stimulus Measurement during Lunar Missions ... Sweat: A Non-Invasive, Time Efficient Means of Monitoring Bone Resorption ...

Content of cyclic nucleotides and activity of acid and alkaline phosphates were ... calcium, sodium, potassium, phosphorus, and acid and alkaline phosphates ... in activity of tartrate-resistant acid phosphatase (an enzyme of bone resorption).

Radiopaque cement containing barium sulfate causes significantly more bone resorption in vivo and in vitro than radiolucent cement. The aim of this study was to investigate the osteolytic potential of an alternative radiopaque agent, triphenyl bismuth (TPB). Bone cement particles containing various concentration of TPB (15 and 25 wt %) prepared by two methods, blending and dissolution, were added to monocytes in a bone resorption assay and the extent of lacunar resorption on dentine slices was determined. The results clearly show that cement particles containing TPB cause less bone resorption than cement particles containing barium sulfate. In addition, our results suggest that TPB prepared by dissolution in bone cement induces less osteolytic response than TPB-cement prepared by blending. The osteolysis in response to bone cement wear particles may therefore be reduced with TPB prepared using the blending technique. PMID:16015616

The cycle characteristics of thermochemical resorption refrigeration system were investigated, and the experimental comparison between the basic resorption cycle and adsorption cycle was performed. Experimental results showed that the conversion rate during the regeneration phase in the resorption refrigeration cycle was higher than that in the adsorption refrigeration cycle at the same constraining temperatures. However, the conversion rate was lower during the cold production phase in the former cycle than in the latter cycle. Moreover, the reaction plateau temperature in the resorption cycle was lower than that in the adsorption cycle at the same regeneration temperature and heat sink temperature. The thermal capacity of metallic part of reactor has a stronger influence on the system pe...

Abstract The osteoclast initiates resorption by creating a resorption lacuna. The ruffled border surrounding the lacunae arises from exocytosis of lysosomes. To dissolve the inorganic phase of the bone, the vacuolar adenosine triphosphatase, located in the ruffled border, pumps protons into the resorption lacunae. The electroneutrality of the lacunae is maintained by chloride transport through the chloride-proton antiporter chloride channel 7. Inhibition of either proton or chloride transport prevents bone resorption. The aims of this study were to validate the human osteoclastic microsome- based influx assay with respect to lysosomal acidification and assess whether it is a reliable test of a compound's ability to inhibit acidification. Investigated were the expression levels of the lysos...

Polgreen LE, Rudser K, Deyo M, Smith A, Baker KS, Petryk A. Changes in biomarkers of bone resorption over the first six-months after pediatric hematopoietic cell transplantation. Abstract:- Bone loss has been observed within the first six-months after HCT in both children and adults. While there is some evidence that bone formation may be reduced in children after HCT, it is currently unknown whether bone resorption is increased. The objective of this prospective study was to evaluate changes in markers of bone resorption over the first six-months after pediatric HCT. Twenty-six participants (eight females) aged 10.9--3.4-yr entered the study prior to HCT. Bone resorption was measured by urine DPD and PYD, and by plasma NTX and CTX. Seventeen participants who completed day +30 visit and ei...

As Americans live longer, degenerative skeletal diseases, such as osteoporosis, become increasingly prevalent. Regardless of cause, osteoporosis reflects a relative enhancement of osteoclast activity. Thus, this unique bone resorptive cell is a prominent therapeutic target. A number of key observati...

Chronic inflammatory disorders, such as rheumatoid arthritis, are often accompanied by systemic bone loss, which is thought to occur through inflammatory cytokine-mediated stimulation of osteoclast resorption and inhibition of osteoblast function. However, the mechanisms involved in osteoblast i...

The occurrence of Sciadicleithrum variabilum on the gills of discus Symphysodon aequifasciatus larvae 7 days after hatching is reported for the first time. This suggests that altricial larvae are susceptible to Monogenea following gill differentiation and before complete yolk resorption.

The pulmonary alveolar epithelium, comprised of alveolar Type I (TI) and Type II (TII) cells, covers more than 99% of the internal surface area of the lungs. The study of isolated and cultured alveolar epithelial TI and TII cells has provided a large amount of information about the functions of both cell types. This chapter provides information about methods for isolating and culturing both of these cell types from rat lungs. PMID:23097106

We investigate surface plasmon modes supported by flat-top silver nano-ridges. We calculate the mode electromagnetic field distribution, the dispersion curve, the travel range, and the figure-of-merit of the nano-ridge mode. We find that the nano-ridge surface plasmon modes are quasi-TEM modes with longitudinal field components three orders of magnitude smaller than the transverse field components. The quasi-TEM nature of mode profiles reveals that the propagation of free electron oscillations on the top of the nano-ridge contributes mainly to the tightly confined ridge mode. We also find that as the width of the nano-ridge decreases, the ridge mode becomes more tightly confined on the ridge top. As the width of the nano-ridge increases, the nano-ridge mode approaches two decoupled right-angle wedge plasmon modes.

Background:- Chronic alcohol abuse causes oxidative stress, impairs alveolar macrophage immune function, and increases the risk of pneumonia and acute lung injury. Recently we determined that chronic alcohol ingestion in rats decreases zinc levels and macrophage function in the alveolar space; provocative findings in that zinc is essential for normal immune and antioxidant defenses. Alveolar macrophage immune function depends on stimulation by granulocyte/monocyte colony-stimulating factor, which signals via the transcription factor PU.1. In parallel, the antioxidant response element signals via the transcription factor Nrf2. However, the role of zinc bioavailability on these signaling pathways within the alveolar space is unknown. Methods:- To determine the efficacy of dietary zinc supple...

Rationale: Endothelin-1 (ET-1) is increased in patients with high-altitude pulmonary edema and acute respiratory distress syndrome, and these patients have decreased alveolar fluid reabsorption (AFR).

The rate of cortical bone resorption was assessed from long-term in vivo measurements of 90Sr content in the skeleton for men aged 50-80 years and for women 0-30 years after menopause. Measurements of 90Sr were conducted with a whole body counter for residents of the Techa Riverside communities (Southern Urals, Russia), who ingested large amounts of 90Sr as a result of releases of liquid radioactive wastes into the river from the Mayak plutonium facility in early 1950s. The results of this study showed an increase in the rate of cortical bone resorption in both men and women, as based on the use of accidentally ingested 90Sr as a tracer for bone metabolism. In men there was a continuous gradual increase in the rate of cortical bone resorption after 55 years from 2.8 to 4.5%/year by the age of 75 years. In women, there was a doubled increase in the rate of cortical bone resorption after menopause of up to 6%/year; then the rate remained unchanged for 10-12 years with a subsequent gradual decline down to 5-5.5%/year. Comparison of the rate of cortical bone resorption in men and women older than 55 years showed that women expressed significantly higher levels of cortical bone resorption.

Resorption of the tail of the anuran larva during metamorphosis is induced by the thyroid hormones. In contrast, the pituitary hormone prolactin favors growth of the tail fin and inhibits resorption. The present investigations were designed to explore the mechanisms by which the thyroid hormones and prolactin bring about their cellular effects. Incubation of explants of tail fin with derivatives of cAMP was shown to inhibit T/sub 4/-induced resorption of explants in a manner similar to that of prolactin. Likewise, inhibition of phosphodiesterases also inhibited resorption. Prolactin, however, failed to alter the levels of cAMP in cultured explants of tail fin. Although cAMP antagonizes the resorptive effects of T/sub 4/, prolactin apparently does not act by elevating cellular levels of that cyclic nucleotide. Newly synthesized proteins from explants of tail fin were examined by isotopical labeling followed by two-dimensional gel electrophoresis and fluorography. Incorporation of /sup 35/S-methionine into four proteins was increased within 8 to 48 hours after exposure of explants to T/sub 4/. Three of the same proteins appeared to be synthesized more rapidly in explants of fin from tadpoles at metamorphic climax than in fin from tadpoles of premetamorphic stages. These results indicate that treatment of explants with T/sub 4/ or elevation of endogenous levels of thyroid hormones during spontaneous metamorphosis increased the relative rates of synthesis of several proteins. Those proteins are potentially involved in initiating the effects of T/sub 4/ which lead to cell death and resorption of the tail.

The increased bone remodeling in women after menopause induces an imbalance between bone resorption and formation, leading to decreased bone mass, altered bone microarchitecture, and increased fracture risk. Current antiosteoporotic drugs decrease bone remodeling or increase bone formation. Strontium ranelate (Protelos) is a newly developed antiosteoporotic drug that acts by reducing bone resorption and promoting bone formation, thereby inducing a positive bone balance. In rat and mouse culture models, strontium ranelate enhances preosteoblastic cell replication and bone formation markers. In contrast, it decreases rodent osteoclastic cell resorbing activity and human osteoclast differentiation, and increases rabbit osteoclast apoptosis. In vivo, strontium ranelate increases bone formation and reduces bone resorption in mice, resulting in increased vertebral bone mass. In rats, strontium ranelate increases bone mass and improves microarchitecture and bone geometry, resulting in increased bone resistance. In ovariectomized rats, strontium ranelate decreases bone resorption but maintains high bone formation, resulting in improved bone microarchitecture and increased bone mass and strength. In clinical trials, serum alkaline phosphatase levels increased whereas serum CTX levels simultaneously decreased in patients treated with Protelos versus placebo at all time-points. In these trials, histomorphometric analysis of bone biopsies showed that the osteoblast surface and mineral apposition rate increased whereas bone resorption parameters tended to decrease in treated patients compared to the placebo group. These preclinical and clinical data indicate that strontium ranelate acts by increasing bone formation and decreasing bone resorption, thus rebalancing bone turnover in favour of bone formation, an effect that results in increased bone mass and strength. PMID:16735840

In the present study, osteoclasts were isolated from hen medullary bones at the formative and resorptive phases. The cells were cultured on glass culture dishes and bone slices. After culturing, the adhesion activity of the isolated osteoclasts with the substrates was estimated with a light microscope, and the surfaces of the bone slices were observed with a scanning electron microscope. The results showed that the adhesion activity of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts is higher at the bone resorptive phase than at the bone formative phase, and this tendency in isolated osteoclasts was observed more frequently on the bone slices than on the glass culture dishes. Furthermore, scanning electron microscopy showed that the isolated osteoclasts in the bone resorptive phase adhered to the bone surface with developed-cytoplasmic projections and formed broad pits where collagen fibrils were exposed. On the other hand, isolated osteoclasts in the bone formative phase adhered to the bone slice with board-shaped cytoplasmic projections and did not form any pits. These results suggest that isolated osteoclasts in the bone resorptive phase have a high level of adhesion activity and actively resorb the bone, whereas isolated osteoclasts in the bone formative phase have a low level of adhesion activity and cease bone resorption. The procedure reported here is useful for studying the bone-resorptive mechanism of authentic osteoclasts.   

Plant nutrient recycling is an important mechanism for nitrogen (N) retention in plants and has been identified as a means for reducing N losses in perennial grass systems managed for biomass production. Warm-season (C4 photosynthesis) prairie grasses are thought to be inherently good at recycling N, because they often thrive in nutrient-limited native grasslands where N recycling strategies would be advantageous. Results from studies of plant responses to altered N resources and the subsequent ability or need for plants to resorb N in high-productivity environments have been equivocal. We addressed N resorption of four species -- Panicum virgatum in a switchgrass monoculture, and Andropogen gerardii, Sorghastrum nutans and Helianthus grosseserratus in a restored prairie -- and their responses to fertilizer additions of 0, 50, or 150 kg N ha-1 on productive mollisols. We hypothesized that senesced leaf N (the final N concentration retained in a senesced leaf) would increase with fertility, while N resorption efficiency (the proportion of original green leaf N resorbed after senescence) would decrease with fertility. N resorption efficiency rates in the prairie differed mainly by species without significant treatment effects. Helianthus grosseserratus resorption efficiency was highest (69.0 ± 2.6% [s.e.]), followed by Sorghastrum nutans (47.9 ± 5.4%) and Andropogen gerardii (35.3 ± 5.7%). Panicum virgatum resorption efficiencies responded opposite to our predictions with the highest resorption rates in the high-fertility treatment (62.9 ± 5.7%) and the lowest resorption rates in the unfertilized treatment (49.4 ± 6.1%). Fertilizer effects were only significant in senesced Panicum virgatum leaves, but across all species, plants with high green leaf N tended to also have higher senesced leaf N. This suggests that plants with high N resorption efficiencies may resorb a higher proportion of original leaf N because there is more N to remobilize. However, these plants were unable to reduce N concentrations to the low levels of their unfertilized counterparts. Although N resorption efficiency is an important strategy for plants in N-limited environments such as native grasslands, in fertilized agroecosystems senesced leaf N may be a better measure of potential N loss. Fertilizing switchgrass produced a low yield response along with increased senesced leaf-N, which demonstrates the challenge of limiting N losses when fertilizing species that exhibit incomplete resorption in high-productivity environments.

Dec 14, 1970 ... an Integrated Medical and Behavioral Laboratory Measurement System. IMBLMS will be a highly flexible, state-of-the-art system, capable of acquiring, displaying, analyzing, and ... B Measurement Requirement Data Sheets. C Laboratory ..... ALVEOLAR VENTILATION. ALVEOLAR ..... o Pneumonia/pleurisy ...

Premature infants are at risk for bronchopulmonary dysplasia, a complex condition characterized by impaired alveolar development and increased alveolar epithelial apoptosis. The functional involvement of pulmonary apoptosis in bronchopulmonary dysplasia- associated alveolar disruption remains undetermined. The aims of this study were to generate conditional lung-specific Fas-ligand (FasL) transgenic mice and to determine the effects of FasL-induced respiratory epithelial apoptosis on alveolar remodeling in postcanalicular lungs. Transgenic (TetOp)(7)-FasL responder mice, generated by pronuclear microinjection, were bred with Clara cell secretory protein (CCSP)-rtTA activator mice. Doxycycline (Dox) was administered from embryonal day 14 to postnatal day 7, and lungs were studied between embryonal day 19 and postnatal day 21. Dox administration induced marked respiratory epithelium-specific FasL mRNA and protein up-regulation in double-transgenic CCSP-rtTA(+)/(TetOp)(7)-FasL(+) mice compared with single-transgenic CCSP-rtTA(+) littermates. The Dox-induced FasL up-regulation was associated with dramatically increased apoptosis of alveolar type II cells and Clara cells, disrupted alveolar development, decreased vascular density, and increased postnatal lethality. These data demonstrate that FasL-induced alveolar epithelial apoptosis during postcanalicular lung remodeling is sufficient to disrupt alveolar development after birth. The availability of inducible lung-specific FasL transgenic mice will facilitate studies of the role of apoptosis in normal and disrupted alveologenesis and may lead to novel therapeutic approaches for perinatal and adult pulmonary diseases characterized by dysregulated apoptosis. PMID:18535181