Open-Healing Socket Preservation with a Novel Dense Polytetrafluoroethylene (dPTFE) Membrane: A Retrospective Clinical Study.

Background and objectives: Non-resorbable dense polytetrafluoroethylene (dPTFE) membranes are widely used for regeneration procedures, alone or in combination with particulate materials. The aim of this work was to examine the efficacy of a newly developed dPTFE membrane in the management of extraction socket healing. Materials and Methods: The extraction premolar sockets of 44 patients (20 men and 24 women) were preserved. One group received prosthetic rehabilitation with a fixed partial denture (FPD) (PROS group, N = 19) and a second group received immediate implant placement (IMPL group, N = 25). The PROS group sockets were augmented with a bovine derived xenograft and covered with a newly developed dPTFE membrane prior to FPD rehabilitation. Results: In the IMPL group, socket preservation was combined with immediate implant placement. Before (T0) and 6 months after surgery (T1), horizontal and vertical dimensions were measured with customized stents. No significant differences in alveolar bone loss from T0 to T1 were observed between the PROS and IMPL groups in the horizontal dimension for any tooth type. There was a significant difference in alveolar bone loss from T0 to T1 between the two groups for only single-rooted maxillary premolars in the vertical dimension. Conclusions: The use of the examined new dPTFE membrane consistently led to the preservation of hard tissue in the extraction sites.

The use of TLR2 modified BMSCs for enhanced bone regeneration in the inflammatory micro-environment.

The repair of periodontal bone tissue defects in patients with periodontitis is one of the major challenges for dentists. Stem cell-based bone regeneration has been considered as a promising strategy to restore the lost periodontal bone tissue. However, the local inflammatory environment of periodontal tissue affects stem cell-based periodontal bone regeneration. Toll-like receptor 2 (TLR2), a member of the TLR family, plays an important role in regulating immunoreaction. Previous studies have shown that the activation of TLR2 signaling pathway is involved in enhancing tissue vascularization and wound healing. However, the mechanisms underlying the therapeutic effects of TLR2 on regulating bone marrow stromal cells (BMSCs) mediated periodontal bone tissue regeneration still need to be further investigated. In this study, we tested the effect of TLR2 on regulating BMSCs mediated alveolar bone regeneration by establishing a TLR2 gene-modified canine BMSCs using a lentivirus. Activation of TLR2 significantly enhanced the expression of hypoxia-inducible factor-1α (HIF-1α) and bone morphogenetic protein 2 (BMP-2) and then upregulated the expression of their downstream osteogenic and angiogenic related gene in BMSCs. TLR2-BMSCs mediated bone regeneration in canine tooth extraction sockets under an inflammatory environment demonstrated that activation of the TLR2 signaling pathway significantly stimulated BMSCs meditated angiogenesis and osteogenesis.

Low-Intensity Pulsed Ultrasound Prevents Development of Bisphosphonate-Related Osteonecrosis of the Jaw-Like Pathophysiology in a Rat Model.

We developed a rat model of bisphosphonate-related osteonecrosis of the jaw (BRONJ) by removing a maxillary molar tooth (M1) from ovariectomized rats after treatment with alendronate. To mimic periodontitis, some of the rats were administered Porphyromonas gingivalis (p. gingivalis) at the M1 site every 2 to 3 d for 2 wk. Rats pretreated with alendronate plus p. gingivalis showed delayed healing of socket epithelia, periosteal reaction of alveolar bone formation and lower bone mineral density in the alveolus above adjacent M2 teeth. These abnormalities were prevented by tooth socket exposure to 20 min/d low-intensity pulsed ultrasound (LIPUS), which restored diminished expression of RANKL, Bcl-2, IL-6, Hsp70, NF-κB and TNF-α messenger ribonucleic acids in remote bone marrow, suggesting LIPUS prevented development of BRONJ-like pathophysiology in rat by inducing systemic responses for regeneration, in addition to accelerating local healing. Non-invasive treatment by LIPUS, as well as low-level laser therapy, may be useful for medication-related osteonecrosis of the jaw patients.

Delayed Socket Healing After Dental Extraction in Patients Undergoing Myelosuppressive Chemotherapy for Hematological Malignancy: Incidence and Risk Factors.

PURPOSE: The purpose of this study was to measure the frequency and identify factors associated with delayed socket healing after dental extraction in patients undergoing myelosuppressive chemotherapy for hematologic malignancy. MATERIALS AND METHODS: This prospective cohort study focused on delayed healing after extraction in patients with hematologic malignancy. Sockets with delayed healing were defined as those with intense pain and bone exposure 1 week postoperatively. Patients with and without delayed socket healing were compared using the Fisher exact test and Mann-Whitney U test with some variables. Receiver operating characteristics curve analysis was conducted to define cutoff values for delayed healing. RESULTS: One hundred ninety-four dental extractions in 93 patients (median age, 64 yr; range, 20 to 85 yr) were analyzed. The incidence of delayed socket healing was 7.5% (7 of 93 patients). There was no postoperative bleeding. Older age, type of hematologic malignancy (acute leukemia), shorter time from dental extraction to initiation of chemotherapy, low platelet count or hemoglobin level, requirement for red blood cell concentrate or platelet transfusion, and use of an absorbable hemostatic agent were statistically associated with the occurrence of delayed socket healing. Platelet and hemoglobin cutoffs were 4.6 × 104/µL and 7.7 g/dL, respectively. CONCLUSIONS: Although dental extraction can be safely performed in patients undergoing myelosuppressive chemotherapy for hematologic malignancy, oral surgeons should understand the potential risk for delayed socket healing. When considering dental extraction, patients with hematologic malignancy and low hemoglobin or platelet levels should be informed about the possibility of delayed socket healing.

Healing of Postextraction Sockets Preserved With Autologous Platelet Concentrates. A Systematic Review and Meta-Analysis.

PURPOSE: The true benefit of autologous platelet concentrates (APCs) for enhancing the healing of postextraction sites is still a matter of debate, and in recent years several clinical trials have addressed this issue. The purpose of this study was to determine the effectiveness of an APC adjunct in the preservation of fresh extraction sockets. MATERIALS AND METHODS: An electronic search was performed on Medline, Embase, Scopus, and the Cochrane Central Register of Controlled Trials. Only controlled clinical trials or randomized clinical trials were included. Selected articles underwent risk-of-bias assessment. The outcomes were complications and adverse events, discomfort and quality of life, bone healing and remodeling assessed by histologic and radiographic techniques, and soft tissue healing. RESULTS: Thirty-three comparative studies were included. Nine articles had a parallel design and 24 had a split-mouth design. Twenty studies were considered to have a low risk of bias and 13 were considered to have a high risk. Overall, 1,193 teeth were extracted from 911 patients. Meta-analysis showed that soft tissue healing, probing depth at 3 months, and bone density at 1, 3, and 6 months were statistically better for the APC group. Qualitative analysis suggested that APCs might be associated with a decrease in swelling and trismus. However, no relevant difference among groups was found for probing depth at 1 month, incidence of alveolar osteitis, acute inflammation or infection, percentage of new bone, and indirect measurement of bone metabolism. CONCLUSION: APCs should be used in postextraction sites to improve clinical and radiographic outcomes such as bone density and soft tissue healing and postoperative symptoms. The actual benefit of APCs on decreasing pain in extraction sockets is still not quantifiable.

Efficacy of bone substitute material in preserving volume when placing a maxillary immediate complete denture: study protocol for the PANORAMIX randomized controlled trial.

BACKGROUND: Bone preservation is an essential issue in the context of last teeth extraction and complete edentulism. The intended treatment, whether a complete denture or an implant placement, is facilitated with a voluminous residual ridge. Bone resorption after multiple extractions has not been as well studied as the bone resorption that occurs after the extraction of a single tooth. Recent advances in bone substitute materials have revived this issue. The purpose of this study is to evaluate the interest in using bone substitute material to fill the socket after last teeth extraction in a maxillary immediate complete denture procedure compared with the conventional protocol without socket filling. METHODS/DESIGN: A randomized, controlled, clinical trial was designed. The 34 participants eligible for maxillary immediate complete denture were divided into two groups. Complete dentures were prepared despite persistence of the last anterior teeth. The control group received a conventional treatment including denture placement immediately after extractions. In the experimental group, in addition to the immediate denture placement, a xenograft bone-substitute material (Bio-Oss Collagen®) was placed in the fresh sockets. The primary outcome of the study is to compare mean bone ridge height loss 1 year after maxillary immediate complete denture placement, with or without bone-substitute material, in incisor and canine sockets. The secondary outcomes are to compare the average bone ridge height and width loss for each extraction site. An original quantitative evaluation method using cone beam computed tomography was designed for reproducible measurements, with a radio-opaque denture duplicate. Two independent operators perform the radiologic measurements. DISCUSSION: The immediate complete denture technique limits bone resorption in multiple extraction situations and thus allows better denture retention and better options for implant placement. To compare the benefit of using any bone socket-filling material, we proposed a quantitative evaluation protocol of resorption in the specific case of the last anterior maxillary teeth extraction with immediate denture placement. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02120053 . Registered on 18 April 2014.

Alveolar socket preservation technique: Effect of biomaterial on bone regenerative pattern.

BACKGROUND: There is a lack of evidence in the literature on the correlation between histomorphometric findings and gene/protein expression markers for bone metabolism. AIM: Evaluation of the histological features, changes in protein expression and gene activation for specific markers of bone metabolism following application of the alveolar ridge preservation technique with magnesium-enriched hydroxyapatite (MgHA). MATERIALS AND METHODS: For each patient (n=15), bone samples were harvested after tooth extraction and processed for immunohistochemical and gene expression analysis (T0). Then, all alveolar sockets were grafted with MgHA. After 4 months (T1), bone samples were harvested for histomorphometrical, immunohistochemical and gene expression analysis. Gene expression and protein expression were evaluated for: RANK, RANKL, OPG, IL-6, TNF-α. RESULTS: For all markers, gene expression increased, but not significantly, from T0 to T1. The mean RANKL/OPG ratio was 1.88±1.24. Protein expression increased significantly (p<0.05) for TNF-α, IL-6, RANK and RANKL. Histomorphometrical features at T1 were not significantly related to protein expression at T0. CONCLUSIONS: After ridge preservation with MgHA, markers for bone catabolism were activated. No significant correlation was found between histomorphometrical features of the regenerated tissue and protein expression at baseline.

The non-healing extraction socket: a diagnostic dilemma - case report and discussion.

STATEMENT OF THE PROBLEM: Delayed healing, or failure of the alveolus to heal post exodontia, is not an uncommon finding in both primary care and hospital practice. Local factors dominate and the majority of cases are the result of clot dissolution, secondary infection, foreign bodies, etc. However, potentially life-threatening, malignant lesions complicating healing can be overlooked and underestimated due to their rare occurrence. PURPOSE OF THE REVIEW: This article presents a contemporary review of the normal physiological process that directs healing within the extraction socket and a differential diagnosis for delayed healing or failure of healing following extraction, with guidance on appropriate management. METHOD: A case report of a squamous cell carcinoma presenting in the clinical setting of a non-healing extraction socket, and a discussion of local and systemic factors that may interfere with healing, are presented. CONCLUSION: The aetiologies of delayed healing and failure of the extraction site to heal are diverse, and the process can be affected by local and systemic factors alike.'Given that neoplastic lesions are relatively rare, it is therefore all the more important for GDPs to remain cognisant of the diagnostic red flags that may raise suspicions of a mitotic lesion to ensure that appropriate referral pathways are instituted.

Alveolar dimensional changes relevant to implant placement after minimally traumatic tooth extraction with primary closure

The purpose of this study is to evaluate the dimensional changes that occur in the alveolar ridge after minimally traumatic tooth extraction by means of computed tomography (CT), with special focus on the portion of bone supporting the gingival zenith. Twenty subjects with indication for singlerooted tooth extraction and preserved alveolar walls were selected for this study. After a minimally traumatic extraction, two CT scans were performed; the first within 24 hours postextraction (TC1) and the second 6 months (TC2) later. A radiographic guide with a radiopaque marker was used to obtain references that enabled accurate measurements over time, in both vertical and horizontal directions. The bone crest immediately apical to the gingival zenith was identified and termed “osseous zenith”. The displacement of the osseous zenith in horizontal and vertical direction was analyzed and correlated with several alveolar anatomical variables with the aim of identifying possible predictors for bone remodeling. Dimensional changes that occur in postextraction sockets within a 6month period showed significant vertical and horizontal displacement of the osseous zenith (p<0.001). Mean vertical resorption was 2.1 ± 1.7 mm, with a median of 1.9 mm and a range of 0.2 to 7.5 mm. Mean horizontal resorption was 1.8 ± 0.8 mm with a median of 1.7 mm and a range of 0.6 to 4.4 mm. However, no correlation was found between the width of the facial alveolar crest and the displacement of the osseous zenith. The results of the present study showed that if the width of the facial crest at the apicalcoronal midpoint is less than 0.7 mm, a high degree of displacement of the osseous zenith (> 3 mm) should be expected. The present study suggests that the width of the alveolar crest at its midlevel, rather than crestal width, may be correlated with the displacement of the osseous zenith.

El objetivo del presente estudio es evaluar los cambios dimen sio nales que ocurren en el reborde alveolar luego de realizar una exodoncia atraumática mediante tomografía computada, con especial atención en el tejido óseo que soporta el cénit gingival. Se seleccionaron 20 sujetos con indicación de exodoncia de piezas unirradiculares y que presentaban las paredes alveolares conservadas. Luego de llevar a cabo una exodoncia atraumática se realizaron dos tomografías computadas (TC); la primera dentro de las 24 hs postexodoncia (TC1) y la segunda a los 6 meses (TC2). Se utilizó una guía radiológica con un marcador radiopaco para obtener medidas precisas en el tiempo, tanto en el plano horizontal como vertical. Se identificó la cresta ósea inmediatamente apical al cénit gingival y se definió como “cénit óseo”. Se realizó un análisis del desplazamiento del cénit óseo en el plano horizontal y vertical y se correlacionó con diferentes variables anatómicas con el objetivo de determinar posibles predictores del remo delado óseo. Los cambios dimensionales que ocurren 6 meses postexodoncia mostraron un desplazamiento significativo del cénit óseo (p<0.001) . La reabsorción vertical promedio fue de 2.1 ± 1.7 mm con una media de 1.9 mm y un rango de 0.2 a 7.5 mm. El promedio de reabsorción horizontal fue de 1.8 ± 0.8 mm con una media de 1.7 mm y un rango de 0.6 a 4.4 mm. No se halló correlación entre el ancho de la cresta vestibular y el desplazamiento del cénit óseo. Los resultados del presente estudio mostraron que si el ancho de la cresta vestibular en el punto medio (en sentido apicocoronal) es menor a 0.7mm se puede esperar un desplazamiento del cénit óseo (>3mm). Este estudio sugiere que el ancho de la cresta alveolar en su punto medio podría predecir el desplazamiento del cénit óseo.

Regeneración ósea guiada en defectos de tipo II: revisión bibliográfica y presentación de un caso clínico / Guided bone regeneration in type II defects: review of the literature and report of a clinical case

La regeneración ósea guiada es una técnica capaz depromover la neoformación ósea. A través de la aplicaciónde la misma se pueden corregir los defectosóseos como dehiscencias, fenestraciones y defectoscircunferenciales similares a los causados por unaextracción dentaria. Esta técnica permite además, elaumento horizontal y vertical del reborde alveolar.La finalidad de este trabajo es la de realizar una revisiónbibliográfica para evaluar los beneficios de laregeneración ósea guiada en defectos de tipo II.

Guided bone regeneration is a techniquecapable of promoting the new bone formation.The bone defects such as dehiscences andfenestrations circumferential defects similar to thosecaused by a tooth extraction could becorrect through the application of the same.This technique also allows increased horizontaland vertical alveolar ridge. The purpose of thiswork is the carry out of a literature review toevaluate the benefits of bone regenerationguided defects in type II.

Immediate effects of tooth extraction on ridge integrity and dimensions.

OBJECTIVES: This study aims to assess possible immediate post-extraction changes in ridge integrity and width. METHODS: Tooth extractions (53 teeth in 30 adults) were performed following atraumatic techniques. Root trunk and ridge width were measured at the crest level in buccolingual direction. Similarly, socket width and buccal plate thickness were also determined. Pre- and post-extraction buccal plate dehiscence, fenestration, or fracture was recorded. Diameter and length of extracted tooth root were also measured. Multinomial logistic regression was used to reveal relationships between ridge outcome (expanded, stable, or collapsed groups) and assessed tooth/site parameters. RESULTS: Post-extraction, buccal plate fracture developed in 5 (9%), dehiscence in 15 (28%), and complete buccal plate loss in 2 sites (4%). Following extraction, ridge width was expanded in 30 (57%), collapsed in 12 (23%), and remained unchanged in 11 (21%) sites. In most sites (72%), post-extraction socket size was wider than pre-extraction root trunk width (p < 0.0001). Socket size was a statistically significant predictor for ridge outcome (expansion or collapse compared to stable) (p < 0.01). CONCLUSION: Loss of ridge integrity is uncommon, while ridge width expansion is a common finding immediately following tooth extraction. The significance of such expansion compared to integrity of socket walls remains to be established. CLINICAL RELEVANCE: Tooth extraction approaches that preserve ridge integrity are accompanied by mainly ridge expansion in ridge width. The significance of such immediate changes for the long-term ridge outcomes (i.e., effect on bone remodeling especially in relation to buccal bone integrity) needs further investigation.

Implante post exodoncia y provisionalización inmediata: reporte de un caso clínico / Postextraction implant and immediate provisionalization: report of a clinical case

La colocación de implantes dentales es una alternativa de tratamiento que ofrece La colocación de implantes dentales son una alternativa de tratamiento que ofrece buenos resultados para dientes que por distinta causa están indicados a la exodoncia. Los implantes dentales inmediatos a la extracción dental surgen a la exigencia de acortar los tiempos de tratamiento y, sobre todo, a la necesidad de preservar las estructuras alveolares que sin ellas estarían destinadas a atrofiarse. Presentamos un caso tratado con la colocación de un implante post extracción y el manejo de tejidos periimplantarios con provisionalización inmediata.

Dental Implant placement is a treatment option that provides good results for teeth thatby any chance have been planned to be extracted Immediate implants arise for the requi-rement to shorten overall treatment time but also to preserve alveolar structures whichwill atrophy without them. We present a case report about an immediate dental implantand immediate provisionalization to manage peri-implant tissues.

Tissue remodeling after bone expansion in grafted and ungrafted sockets.

PURPOSE: The aim of this clinical study was to assess horizontal width changes in grafted and ungrafted sites after bone expansion and implant placement. MATERIALS AND METHODS: Twenty-three patients were included in this prospective study. Each patient required extraction of two teeth and replacement with implants. After dental extraction in 23 alveoli (group 1), a collagen sponge was used to cover fresh sockets, and the remaining 23 alveoli (group 2) were grafted with corticocancellous porcine bone. Three months after extraction, bone expansion was performed in each site, and 46 dental implants were placed. To evaluate tissue volume changes, the variations in width of the buccal ridge were recorded with a periodontal probe immediately after tooth extraction, 3 months later (before implant placement), and 3 months after implant placement. RESULTS: In group 1, at 3 months after implant placement, mean volume changes of +1.6 ± 0.8 mm for incisors and canines, +1.4 ± 0.5 mm for premolars, and +0.8 ± 0.5 mm for molars were seen. In group 2, mean changes of +1.5 ± 0.8 mm for incisors and canines, +1.3 ± 0.3 mm for premolars, and +2.8 ± 0.6 mm for molars were observed. Statistically significant differences were found only for molars. CONCLUSIONS: In both groups, incisor, canine, and premolar sites showed no differences in volume changes, but statistically significant differences were found between molars in the two groups; the biomaterial graft prevented collapse of the large defects and significant volume loss.

Evaluation of a dense polytetrafluoroethylene membrane to increase keratinized tissue: a randomized controlled clinical trial.

BACKGROUND: The presence of an adequate zone of keratinized tissue has been associated with implant health. This study evaluated the increasing of the zone of keratinized tissue using dense polytetrafluoroethylene (d-PTFE) membranes over extraction sites, without primary closure. MATERIALS AND METHODS: Fifteen sites received d-PTFE membranes. The control sites received no membranes. All cases were sutured with no attempt to achieve primary closure. Before surgery, initial measurements of buccal and lingual keratinized tissue were taken from the mucogingival line (MGL) to the most coronal gingival margins. Final measurements were taken from the buccal MGL to the lingual MGL, 60 and 90 days after extractions. RESULTS: In the test group, a mean increase in the zone of keratinized tissue of 7.06 ± 2.63 mm and 6.6 ± 2.84 mm was observed in 60 and 90 days, respectively. In the control group, a mean increase of 2.46 ± 1.59 mm and 1.40 ± 1.40 mm was observed in 60 and 90 days, respectively. CONCLUSION: Nonexpanded d-PTFE membranes can predictably be used to increase the zone of keratinized tissue in preparation to implant placement.

Extraction sockets: erratic healing impeding factors.

AIM: The aim of this exploratory study was to analyse prevalence of extraction sockets showing erratic healing and evaluate factors potentially impeding healing. METHODS: Erratic healing was defined as extraction sites showing clinical observations of fibrous scar tissue occupying the extraction site rather than bone following 12 or more weeks of healing. Computerized tomography was used to evaluate characteristics and calculate Hounsfield unit scores for sites showing erratic healing. RESULTS: A total of 1226 dental records from Seoul National University Dental Hospital archives including patients subject to extractions prior to implant placement were evaluated. Seventy subjects (5.71%) and 97 sites (4.24%) exhibited erratic extraction socket healing. Maxillary incisor/canine sites showed the lowest (0.47%), whereas mandibular molar sites the highest (5.41%) occurrence. In the multivariable analysis, erratic healing was more likely to occur in subjects <60 years old (OR = 2.23, 95%CI = 1.26-3.94), subjects with hypertension (OR = 2.37, 95%CI = 1.24-4.55), in molar sites (OR = 4.91, 95%CI = 1.41-17.07), and following single tooth extractions (OR = 2.98, 95%CI = 1.36-6.53). Computerized tomography showed the highest incidence of bone loss for the buccal wall (49.3%). CONCLUSION: Erratic extraction socket healing appears a not uncommon sequel and local factors seem to be major contributors to its occurrence.

The use of a polycaprolactone-tricalcium phosphate scaffold for bone regeneration of tooth socket facial wall defects and simultaneous immediate dental implant placement in Macaca fascicularis.

Bone regeneration and aesthetic outcomes may be compromised when immediate implants are placed at extraction sites with dehiscence defects. The aim of this study was to compare, in a monkey model, peri-implant bone regeneration and implant stability after immediate implant placement into tooth sockets with facial wall defects in two treatment groups. In eight control monkeys, the bony defect was reconstructed with autogenous particulate bone, whereas in 10 test monkeys a polycaprolactone-tricalcium phosphate (PCL-TCP) scaffold was used. The monkeys were sacrificed after 6 months and the specimens were analyzed by histology and histomorphometry. Better maintenance of facial bone contour was noted in the test group; however, bone regeneration was seen only at areas adjacent to a bony wall of the defect. The mean bone-to-implant contact was 27.6 ± 19.1% (control group) versus 6.8 ± 7.9% (test group). The mean bone area percentage was 11.8 ± 10.1% (control group) versus 6.8 ± 6.9% (test group). Implant survival was 100% at 6 months for both the groups. It was concluded that although the use of a PCL-TCP scaffold showed better maintenance of the alveolar contour as compared to autogenous particulate bone at 6 months, there was minimal bone regeneration within the defect.

Molecular events on tooth socket healing in diabetic rabbits.

Healing of extraction sockets involves complex cellular events such as repair and regeneration of tissue. These events are precisely controlled and regulated by specific signalling molecules such as transforming growth factor beta (TGF-ß), vascular endothelial growth factor (VEGF), bone morphogenetic protein (BMP), and insulin-like growth factor (IGF), which are well-conserved proteins involved in the initial response to injury and repair in soft and hard tissues. We studied 48 rabbits, which were divided into 3 groups of 16 each: the control group, the untreated diabetic group, and the insulin-treated diabetic group. The lower incisor of each rabbit was extracted and, after 2, 10, 20, and 30 days of healing, the expression of TGFß-3, VEGF, IGF-1R, and BMP-4 in the sockets was measured immunohistochemically. Rabbits with untreated diabetes expressed less TGFß-3 than the other groups throughout the healing periods, whereas IGF-1R expression was higher than that in the other groups. This increase in IGF-1R expression was responsible for increasing the healing time in rabbits in the untreated group. The healing of bone in diabetic rabbits that were not treated with insulin was prolonged because of a delay in the onset of cell proliferation and osteoblast differentiation, and the insulin treatment had a direct effect on the expression of TGFß-3 and IGF-1R, which accelerated healing of the socket.

Enhanced bone formation during healing process of tooth sockets filled with demineralized human dentine matrix.

BACKGROUND: Orthodontic procedures are often limited by the presence of bone defects caused by trauma, periodontal diseases or surgeries, thus requiring the development of materials capable to compensate such deficiencies. Since bone morphogenetic proteins (BMPs) are indicative of bone reconstitution, this study aimed to evaluate histological and immunohistochemically the temporal location of BMP-2 and BMP-4 in osteoblasts of rat alveolar wounds filled with demineralized human dentine matrix (DHDM), used as a graft material. METHODS: After extraction of the upper second molars, the left side alveoli were filled with DHDM and the right side served as the control. The animals were euthanized after 3, 5, 10 and 14 days of surgery. After fixation, demineralization and paraffin embedding, representative samples of each group were stained with H&E and immunohistochemically evaluated. RESULTS: The data showed a statistically significant (p < 0.05) increased number of osteoblasts positively immunostained for BMP-2 and BMP-4 on the experimental side (left) at 10 days. Our results also showed that even when not degraded, dentine matrix was incorporated to new bone formation after 14 days of surgery. CONCLUSIONS: The results suggest that DHDM acts as a scaffold for osteoblast differentiation, actively yielding new bone formation, and it may represent an effective bone implant material.

Maintaining vitality of immediately reimplanted avulsed tooth: two-year follow-up case report.

Management of tooth avulsion in the permanent dentition often presents a challenge. Such injuries should be recognized and treated expeditiously because several studies support a more likely favorable prognosis with timely and appropriate initial management. This article describes the immediate management of an avulsed maxillary permanent incisor with afollow-up of 1 year.

Evaluation of optimal taper of immediately loaded wide-diameter implants: a finite element analysis.

This study aimed to evaluate the effects of different tapering angles of an immediately loaded wide-diameter implant on the stress/strain distribution in bone and implant after implant insertion in healed or fresh molar extraction sockets. A total of 10 finite element (FE) implant-bone models, including 8.1-mm diameter implant, superstructure, and mandibular molar segment, were created to investigate the biomechanical behavior of different implant taper angles in immediate and delayed placement conditions. The degrees of implant taper ranged from 2° to 14°, and the contact conditions between the immediately loaded implants and bone were set with frictional coefficients (µ) of 0.3 in the healed models and 0.1 in the extracted models. Vertical and lateral loading forces of 189.5 N were applied in all models. Regardless of the degree of implant tapering, immediate loading of wide-diameter implants placed in molar extraction sockets generated higher stress/strain levels than implants placed in healed sockets. In all models, the von Mises stresses and strains at the implant surfaces, cortical bone, and cancellous bone increased with the increasing taper angle of the implant body, except for the buccal cancellous bone in the healed models. The maximum von Mises strains were highly concentrated on the buccal cortical struts in the extracted models and around the implant neck in the healed models. The maximum von Mises stresses on the implant threads were more concentrated in the non-tapered coronal part of the 11° and 14° tapered implants, particularly in the healed models, while the stresses were more evenly dissipated along the implant threads in other models. Under immediate loading conditions, the present study indicates that minimally tapered implants generate the most favorable stress and strain distribution patterns in extracted and healed molar sites.