Clinical and radiographic outcomes of a two-piece ceramic implant: one year results from a prospective clinical trial.

OBJECTIVE: To describe the clinical and radiographic performance and survival rate of a new two-piece ceramic implant system after at least 12 months of follow-up. MATERIALS AND METHODS: Sixty-five implants were placed and followed up for at least 12 months (12.3 ± 1.5), in 50 patients. The implants were installed both in fresh extraction sockets and in healed sites and received provisional restoration when the clinical insertion torque was greater than 35Ncm. The primary results describe the survival rate of these implants. Clinical performance was evaluated through the evaluation of the Pink Esthetic Score (PES) and the degree of satisfaction of the patients. Bone loss was measured through radiographic measurements of the marginal bone loss in the mesial (MBLM) and distal (MBLD) sites. RESULTS: The survival rate was 98.5%. The average MBLM was 0.24 mm (± 0.53) and the MBLD was 0.27 mm (± 0.57). A statistical difference was observed only when comparing immediate implants with delayed ones (MBLM - p = 0.046 and MBLD - p = 0.028) and when they received immediate provisionalization or not (MBLM - p = 0.009 and MBLD - p = 0.040). The PES before the intervention (T0) was 13.4 (± 0.8) and the PES at T2 (12-month follow-up) was 12.9 (± 1.5) (p = 1.14). CONCLUSION: The new two-piece ceramic implant used in the present study showed predictable and reliable results, similar to those found with titanium implants after one year of follow-up. CLINICAL RELEVANCE: These implants can be used as an alternative to titanium implants in terms of the marginal bone loss and the degree of patient satisfaction.

Digital workflow for image-guided immediate implant placement by using the socket-shield technique and custom abutment in the esthetic area.

Marginal bone loss around immediately placed implants may compromise esthetic outcomes in the anterior maxilla. The relatively recent socket-shield technique of partial extraction therapy has been described as being useful to maintain the structure of peri-implant tissues. The present technique report introduced a digital workflow to perform image-guided implant placement after partial extraction therapy. In this technique, digital 3-dimensional images are used to plan and orient the flapless surgical procedure and to digitally design a custom abutment based on the natural emergence profile as segmented from the tooth to be extracted.

Tomographic evaluation of the effect of simvastatin topical use on alveolar bone microarchitecture, pain and swelling after mandibular third molar extraction: a randomized controlled trial.

OBJECTIVES: To evaluate the effect of a collagen sponge containing simvastatin on socket healing in terms of bone microarchitecture through tomographic analysis, pain, and swelling after impacted third molar extraction. MATERIALS AND METHODS: In this single-blind, split-mouth, randomized clinical trial, 29 patients undergoing impacted third molar extraction were allocated into two groups: (i) test group, a collagen sponge containing simvastatin was inserted within the sockets; and (ii) control group, in which sockets retained the clot. Bone volume (BV), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular spacing (Tb.Sp), and gray scale were evaluated using cone beam computed tomography (CBCT) acquired immediately postoperative and 3 months after surgery. Pain, swelling, and wound healing were evaluated using the 10-point visual analogue scale, three extra-oral reference measurements, and the Landry index. RESULTS: In total, 22 participants remained in the study; no loss-to-follow-up was related to the intervention. BV and BV/TV were significantly higher at 3 months postoperatively in the test group compared with the control group and were correlated with greater bone trabeculation. Pain, edema, and the Landry index revealed a greater inflammatory response in the test group during early repair. Simvastatin contributed to bone healing, with no adverse effects or postoperative complications. CONCLUSIONS: The absorbable collagen sponge containing simvastatin improved BV, BV/TV, and trabecular bone, indicating the potential of this drug to induce the formation of autogenous bone. CLINICAL RELEVANCE: Intraosseous statins represent a promising, low-cost, and easy-to-use alternative for alveolar ridge preservation and bone regeneration. TRIAL REGISTRATION: Brazilian Registry of Clinical Trials (REBEC), No. RBR-523N7R.

Alveolar socket healing in 5-lipoxygenase knockout aged female mice treated or not with high dose of zoledronic acid.

This study investigated the role 5-lypoxigenase (5-LO) on alveolar socket healing in aged female mice treated with zoledronic acid (ZL). Forty 129/Sv female mice (64-68 weeks old), 20 wild type (WT) and 20 5-LO knockout (5LOKO) were equally distributed according to ZL treatment: WT Control, WT ZL, 5LOKO Control, and 5LOKO ZL. ZL groups were treated with an intraperitoneal injection of 250 µg/Kg of ZL, while controls were treated with saline. Treatments were administered once a week, starting four weeks before surgery for tooth extraction and until 7 and 21 days post-surgery. Mice were euthanized for a comprehensive microscopic analysis (microCT, histomorphometry and immunohistochemistry). WT ZL mice presented intense inflammatory infiltrate (7 days), delayed bone formation (21 days), reduced collagenous matrix quality, and a deficiency in Runx-2 + , TRAP + , and macrophages as compared to controls. 5LOKO ZL animals presented decreased number of Runx-2 + cells in comparison to 5LOKO Control at 7 days, but no major changes in bone healing as compared to WT or 5LOKO mice at 21 days. The knockout of 5LO favored intramembranous bone healing in aged female mice, with a direct impact on inflammatory response and bone metabolism on the development of ONJ-like lesions.

Effects of osteoporosis on alveolar bone repair after tooth extraction: A systematic review of preclinical studies.

OBJECTIVE: This systematic review aimed to address whether the alveolar socket repair after a tooth extraction is impacted by an osteoporotic phenotype and propose methodological observations. DESIGN: A search strategy in MEDLINE/PubMed, EMBASE, Web of Science, and Scopus databases was performed. Quality assessment was carried out through the SYRCLE Risk of Bias tool. RESULTS: Out of the 1147 potentially relevant records, 25 met the inclusion criteria. Most of the studies were performed in rats, and ovariectomy (OVX) was the most frequent osteoporosis induction method. Histomorphometry, micro-computed tomography (microCT), and immunohistochemistry were the main bone repair evaluation methods. Most of the included studies (88 %) presented negative impacts of osteoporosis on the alveolar socket repair. Only three studies (12 %) showed no statistical differences among groups. Overall, most of the quality assessment categories presented a high percentage of unclear risk of bias due to insufficient information in the studies. CONCLUSIONS: The results indicated that an osteoporotic phenotype seems to impair alveolar socket repair after tooth extraction. However, there is still a lack of information and standardization. Therefore, further studies should consider the proposed methodological aspects regarding animal characteristics, OVX associated with a low calcium diet, waiting 8 weeks to osteoporosis induction, maxillary molars as the best option for tooth extraction, confirming and reporting OVX and osteoporosis success, and an appropriate method of repair analysis.

Clinical efficacy of simvastatin gel combined with polypropylene membrane on the healing of extraction sockets: A triple-blind, randomized clinical trial.

OBJECTIVES: This study aimed to evaluate dimensional changes, level of soft tissue healing, and pain/discomfort perception in post-extraction sockets filling with 1.2% simvastatin (SIM) gel covered with polypropylene membranes (PPPM). MATERIAL AND METHODS: Twenty-six post-extraction sockets of posterior teeth were randomly allocated in two groups: (a) socket filling with 1.2% SIM gel and covered with PPPM (n = 13) and (b) socket filling with placebo gel and covered with PPPM (n = 13). Cone-beam computed tomography (CBCT) images before and 90 days after the extraction enabled alveolar bone dimensional changes calculation using horizontal and vertical measurements. The measurements occurred at three different levels for thickness located 1, 3, and 5 mm from the top of the bone crest. The vertical (depth) measure was assessed from the most apical portion of the socket to the bone crest's most coronal portion. Seven days after the extractions, the level of soft tissue healing and pain perception were also analyzed. RESULTS: After 90 days of extractions, the dimensional changes in thickness in the test group were significantly smaller in sections A (p = .044), B (p = .036) and C (p = .048) when compared to the control group. The test group showed a significantly lower height-dimensional change than the control group (p < .0001). Soft tissue healing index (p = .63), perception of pain (p = .23), and number of analgesics consumed (p = .25) were similar between groups. CONCLUSIONS: Simvastatin at 1.2% compared with placebo effectively reduced the dimensional changes in post-extraction sockets covered with PPPM. There was no significant difference in the level of soft tissue healing and postoperative pain between the test and control groups.

Short-term use of an exposed polypropylene barrier in the preservation of alveolar bone after extraction: randomized clinical trial.

This study was performed to evaluate the short-term preservation of alveolar bone volume with or without a polypropylene barrier and exposure of the area after extractions. Thirty posterior tooth extraction sockets were distributed randomly to a control group (n=15; extraction and suture) and a barrier group (n=15; extraction, barrier, and suture). All sutures and barriers were removed 10 days postoperatively. Cone beam computed tomography scans taken with the aid of a tomographic guide were obtained preoperatively, immediately postoperative, and at 120 days postoperative. A visual analysis of the coronal sections of the alveolus was performed, and vertical loss in the mesial, distal, buccal, and lingual bone ridges and horizontal thickness were evaluated. The mean vertical loss after extraction did not differ significantly between the control and barrier groups (Student t-test: mesial P= 0.989, buccal P= 0.997, lingual/palatal P= 0.070, distal P= 0.107). The mean vertical loss at 120 days postoperative did not differ significantly between the control (0.65 mm) and barrier (0.52 mm) groups (P> 0.05), with an effect size of 0.13 mm. At 120 days, the barrier group presented a mean resorption in thickness (0.45 mm) that was significantly lower than that in the control group (0.76 mm) (P= 0.021), with an effect size of 0.31 mm. The polypropylene barrier reduced the horizontal resorption in sockets of posterior teeth after extraction.

Impact of fully or partially guided surgery on the position of single implants immediately placed in maxillary incisor sockets: A randomized controlled clinical trial.

PURPOSE: The aim of this study was to compare the deviation of the implant position after placement in single maxillary incisor post-extraction sockets between fully and partially guided surgery. MATERIALS AND METHODS: Twenty-four patients with a failing maxillary incisor were randomly allocated into two groups: the partially guided surgery (PGS, n = 12) group or fully guided surgery (FGS, n = 12) group. Clinical analyses, intra-oral scans, and computed tomography scans (CT) were initially performed to define the virtual positioning of the implants and fabrication of the 3D printed surgical guides. A narrow, 3.5 × 16 mm implant was placed in each socket. In this moment, the insertion torque (IT) was assessed and resonance frequency analysis (RFA) was performed. All patients received an immediate provisional without occlusal contacts. Another CT scan was performed after the procedures to compare the implant position with the virtually planned position. RESULTS: Significant deviations occurred at the implant apex, according to the global and facial-palatal analyses, in comparison to its cervical position. The PGS group also presented a larger deviation in the MD position. No statistical differences between the groups were detected, however, there was a tendency of lower angular deviation in the PGS group. CONCLUSIONS: While there was a slight deviation from the virtually planned position of the implant to the actual position and a tendency of lower angular deviation in the PGS group, there was no difference among groups regarding its position and primary stability. (UNT: 1111-1214-2812 - http://www.ensaiosclinicos.gov.br/rg/RBR-4tmcrk/).

The effects of intro-oral parathyroid hormone on the healing of tooth extraction socket: an experimental study on hyperglycemic rats.

Objective To investigate the effects of intro-oral injection of parathyroid hormone (PTH) on tooth extraction wound healing in hyperglycemic rats. Methodology 60 male Sprague-Dawley rats were randomly divided into the normal group (n=30) and DM group (n=30). Type 1 diabetes mellitus (DM) was induced by streptozotocin. After extracting the left first molar of all rats, each group was further divided into 3 subgroups (n=10 per subgroup), receiving the administration of intermittent PTH, continuous PTH and saline (control), respectively. The intermittent-PTH group received intra-oral injection of PTH three times per week for two weeks. A thermosensitive controlled-release hydrogel was synthesized for continuous-PTH administration. The serum chemistry was determined to evaluate the systemic condition. All animals were sacrificed after 14 days. Micro-computed tomography (Micro-CT) and histological analyses were used to evaluate the healing of extraction sockets. Results The level of serum glucose in the DM groups was significantly higher than that in the non-DM groups (p<0.05); the level of serum calcium was similar in all groups (p>0.05). Micro-CT analysis showed that the DM group had a significantly lower alveolar bone trabecular number (Tb.N) and higher trabecular separation (Tb.Sp) than the normal group (p<0.05). The histological analyses showed that no significant difference in the amount of new bone (hard tissue) formation was found between the PTH and non-PTH groups (p>0.05). Conclusions Bone formation in the extraction socket of the type 1 diabetic rats was reduced. PTH did not improve the healing of hard and soft tissues. The different PTH administration regimes (continuous vs. intermittent) had similar effect on tissue healing. These results demonstrated that the metabolic characteristics of the hyperglycemic rats produced a condition that was unable to respond to PTH treatment.

Photobiomodulation as an adjunctive therapy for alveolar socket preservation: a preliminary study in humans.

Bone remodeling results in loss of alveolar bone height and thickness. Photobiomodulation (PBM) based on photochemical stimulation by low-intensity lasers emerges as an adjunctive therapy for alveolar socket preservation. Our study aimed to evaluate the effects of PBM therapy on alveolar bone repair. Twenty healthy patients in need of bilateral extraction of lower molars were enrolled in this split-mouth randomized and blind clinical trial. The extraction sites were randomly selected to receive either the PBM therapy with a CW GaAIAs diode laser (808 nm; 0.028 mm2; 0.1 W; 3.6 W/cm2; 89 J/cm2; 2.5 J/point) or no treatment (Control). Bone biopsies were harvested 45 days after the dental extraction and evaluated using micro-computerized tomography (µCT), morphometric, and histological analysis. Data were compared using the paired t test, and the level of significance was set at 5%. Bone surface (p = 0.029), bone surface/total volume (p = 0.028), trabecular number (p = 0.025), and connectivity density (p = 0.029) were higher at the PBM group compared with Control. The histological observations confirmed the µCT findings. PBM samples exhibited higher number of organized and connected bone trabeculae along with higher density of blood vessels than Control. Control samples displayed a dense and highly cellular connective tissue at the central area accompanied by the presence of immature bone trabeculae at the periphery. Our results indicated that the PBM therapy improved the newly bone trabeculae formation and their connectivity which increased bone surface, indicating the positive effect of the laser on alveolar human socket repair.

Alendronate improves bone density and type I collagen accumulation but increases the amount of pentosidine in the healing dental alveolus of ovariectomized rabbits.

BACKGROUND: It has been shown that the oral aminobisphosphonate sodium alendronate (ALN) therapy reduces the risk of main fractures in osteoporotic women, but its effect on the jaw bones is poorly known. Here, we hypothesized that ALN affects the newly formed alveolar bone, particularly the quality of the type I collagen cross-linking. METHODS: Osteoporosis was induced by ovariectomy (OVX) in 6-month old rabbits. Six weeks following surgery, eight animals were treated by oral gavage with ALN (OVX + ALN) and ten received placebo (OVX + Pbo). Another six rabbits which were sham operated also received placebo (SHAM + Pbo). One month following the beginning of treatment, the upper and lower left first premolars were removed. Six weeks later, the upper and the lower right first premolars were also extracted. One month after the second extraction, biopsies were collected from the maxillary extraction sites and collagen crosslinks were analyzed in the newly formed bone tissue by HPLC. Also, at this time, mandibular bone segments were subjected to µCT. RESULTS: Animals treated with ALN achieved a roughly 2-time greater bone volume fraction value at a late healing period than animals in the other groups (p < 0.05). Collagen mean results were 2- to 4-times superior in the OVX + ALN group than in the control groups (p < 0.05). ALN-treated animals presented higher amounts of the non-enzymatic collagen cross-link pentosidine (PEN) than the sham-operated rabbits (p < 0.05), whereas the OVX + Pbo group presented the highest amount of PEN (p < 0.05). CONCLUSION: Alendronate increases bone volume and collagen accumulation, but does not fully rescue the non-osteoporotic alveolar tissue quality as is evident from the increased quantity of pentosidine.

Alveolar bone healing in mice genetically selected in the maximum (AIRmax) or minimum (AIRmin) inflammatory reaction.

The exact role of inflammatory immune response in bone healing process is still unclear, but the success of the alveolar bone healing process seems to be associated with a moderate and transitory inflammatory response, while insufficient or exacerbated responses seems to have a detrimental influence in the healing outcome. In this context, we performed a comparative analysis of mice strains genetically selected for maximum (AIRmax) or minimum (AIRmin) acute inflammatory response to address the influence of inflammation genes in alveolar bone healing outcome. Experimental groups comprised 8-week-old male or female AIRmax and AIRmin submitted to extraction of upper right incisor, and evaluated at 0, 3, 7, 14 and 21 days after upper incision extraction by micro-computed tomography (µCT), histomorphometry, birefringence, immunohistochemistry and molecular (PCRArray) analysis. Overall, the results demonstrate a similar successful bone healing outcome at the endpoint was evidenced in both AIRmin and AIRmax strains. The histormophometric analysis reveal a slight but significant decrease in blood clot and inflammatory cells density, as well a delay in the bone formation in AIRmax strain in the early times, associated with a decreased expression of BMP2, BMP4, BMP7, TGFb1, RUNX2, and ALP. The evaluation of inflammatory cells nature reveals increased GR1+ cells counts in AIRmax strain at 3d, associated with increased levels of neutrophil chemoattractants such as CXCL1 and CXCL2, and its receptor CXCR1, while F4/80+ cell prevails in AIRmin strain at 7d. Also, our results demonstrate a relative predominance of M2 macrophages in AIRmin strain, associated with an increased expression of ARG1, IL10, TGFb, while M1 macrophages prevail in AIRmax, which parallel with increased IL-1B, IL-6 and TNF expression. At late repair stage, AIRmax presents evidences of increased bone remodeling, characterized by increased density of blood vessels and osteoclasts in parallel with decreased bone matrix density, as well increased levels of MMPs, osteoclastogenic and osteocyte markers. In the view of contrasting inflammatory and healing phenotypes of AIRmin and AIRmax strains in other models, the unpredicted phenotype observed suggests the existence of specific QTLs (Quantitative trait loci) responsible for the regulation 'sterile' inflammation and bone healing events. Despite the similar endpoint healing, AIRmax strain delayed repair was associated with increased presence of neutrophils and M1 macrophages, supporting the association of M2 cells with faster bone healing. Further studies are required to clarify the elements responsible for the regulation of inflammatory events at bone healing sites, as well the determinants of bone healing outcome.

Cellular profile of primary molars with pulp necrosis after treatment with antibiotic paste.

The interradicular region of primary molars is permeated by many foramina, channels and accessories that connect the pulp cavity with the periapical tissues anatomically. Thus, pulp decomposition products or drugs used in endodontic treatment can trigger inflammatory reactions. The aim of this study was to evaluate the blood cell profile of the alveolar region after extraction of primary molars treated with CTZ paste. Forty-eight primary molars were selected with clinical and radiographic signs of extraction. The sample was divided into three groups with 16 teeth each: Group 1-healthy teeth; Group 2-untreated decayed teeth; and Group 3-teeth treated with CTZ paste. Immediately after the extraction, blood from the interface of the tooth socket was collected and smears were performed for further evaluation. The slides were stained by the Fast Panoptic® method and analysed by two previously trained examiners who counted the leucocytes in sets of 100 cells/slide, differentiating them into neutrophils, lymphocytes, monocytes, eosinophils and basophils. The data were analysed statistically by the MANOVA test. The blood samples from Group 2 differed significantly from Group 1 samples for all classes of leucocytes, except basophils, with higher average for lymphocytes (62.56), monocytes (7.81) and eosinophils (2.31). For Group 3, there was a relative difference (P < 0.05) to Group 2, of monocytes and eosinophils values. The blood cellularity interface in the tooth socket of primary teeth treated with CTZ paste is similar to those of healthy, exfoliated teeth and physiologically different from untreated decayed teeth.

Hyaluronic acid accelerates bone repair in human dental sockets: a randomized triple-blind clinical trial.

This study evaluated the effects of hyaluronic acid (HA) on bone repair of human dental sockets. Thirty-two lower first premolars were extracted from 16 patients (2 per patient) for orthodontic reasons. Following the extractions, one socket was randomly filled with 1% HA gel, while the other was allowed to naturally fill with blood clot. After 30 and 90 days of surgery, patients underwent cone beam computed tomography. Five central orthoradial slices were captured from each socket. The gray intensity was measured in each image and results were reported as mean percentage of bone formation. The buccolingual alveolar ridge width was measured and dimensional changes were compared between the postoperative intervals. The pattern of alveolar trabecular bone was evaluated through the fractal dimension. Treated sockets showed a higher percentage of bone formation and fractal dimension values (58.17% and 1.098, respectively) compared with controls (48.97% and 1.074, respectively) in the 30-day postoperative period (p < 0.05). After 90 days, there was no significant difference between groups. Additionally, no significant difference was found between groups regarding the alveolar dimensions (p > 0.05). Use of 1% HA gel after tooth extraction accelerates bone repair in human dental sockets.

Tomographic late evaluation of xenogeneic bone grafts in sockets of impacted third molars.

OBJECTIVE: It is necessary to preserve height and thickness of the alveolar bone to facilitate rehabilitation with osteointegratable implants or simply to maintain bone integrity after extraction. Biomaterials associated with resorbable or non-resorbable membranes, when placed in the region of the socket, may contribute to avoid this unwanted reabsorption. OBJECTIVE: The objective of this study was to evaluate the distance of the crest of alveolar ridge to the cementoenamel junction (CEJ) of the lower second molars and the bone density of the third molar socket filled with Gen-Tech®, 5 years after an exodontia using cone beam computed tomography (CBCT) to visualize the central region of the sockets, without overlapping of the buccal and lingual cortical bones. MATERIAL AND METHODS: A total of 12 individuals from an initial group of 39 patients submitted to extraction of the unruptured lower third molars and grafting of an association of inorganic bovine bone matrix, organic bovine bone matrix, collagen and bone morphogenetic proteins (BMP) (Gen-Tech®) on one side and the contralateral sockets filled only by clot, returned to control after 5 years, and were submitted to CBCT. The distance from the crest of alveolar bone to the CEJ and the bone density (BD) were measured using the i-CAT Vision Software. RESULTS: The results showed that the distance from the crest of alveolar bone to the CEJ in the control group was similar to that observed before the exodontia; in the experimental group, this distance was smaller. Considering the BD measurement, a significantly higher density was observed in the experimental group (p<0.05). CONCLUSION: Part of the biomaterial was not absorbed and allowed the stability of the evaluated parameters after 5 years, being able to be used as a bone substitute in the socket.

Alveolar bone healing in rats: micro-CT, immunohistochemical and molecular analysis.

INTRODUCTION: Alveolar bone healing after upper incisor extraction in rats is a classical model of preclinical studies. The underlying morphometric, cellular and molecular mechanism, however, remains imprecise in a unique study. OBJECTIVES: The aim of this study was therefore to characterize the alveolar bone healing after upper incisor extraction in rats by micro computed tomographic (Micro-CT), immunohistochemical and real-time polymerase chain reaction (RT-PCR) analysis. MATERIAL AND METHODS: Thirty animals (Rattus norvegicus, Albinus Wistar) were divided into three groups after upper incisors extraction at 7, 14, and 28 days. Micro-CT was evaluated based on the morphometric parameters. Subsequently, the histological analyses and immunostaining of osteoprotegerin (OPG), receptor activator of nuclear kappa B ligand (RANKL) and tartrate resistant acid phosphate (TRAP) was performed. In addition, RT-PCR analyses of OPG, RANKL, the runt-related transcription factor 2 (RUNX2), osteocalcin (OC), osteopontin (OPN), osterix (OST) and receptor activator of nuclear kappa B (RANK) were performed to determine the expression of these proteins in the alveolar bone healing. RESULTS: Micro-CT: The morphometric parameters of bone volume and trabecular thickness progressively increased over time. Consequently, a gradual decrease in trabecular separation, trabecular space and total bone porosity was observed. Immunohistochemical: There were no differences statistically significant between the positive labeling for OPG, RANKL and TRAP in the different periods. RT-PCR: At 28 days, there was a significant increase in OPG expression, while RANKL expression and the RANKL/OPG ratio both decreased over time. CONCLUSION: Micro-CT showed the newly formed bone had favorable morphometric characteristics of quality and quantity. Beyond the RUNX2, OC, OPN, OST, and RANK proteins expressed in the alveolar bone healing, OPG and RANKL activity showed to be essential for activation of basic multicellular units during the alveolar bone healing.

Tomographic late evaluation of xenogeneic bone grafts in sockets of impacted third molars

Abstract It is necessary to preserve height and thickness of the alveolar bone to facilitate rehabilitation with osteointegratable implants or simply to maintain bone integrity after extraction. Biomaterials associated with resorbable or non-resorbable membranes, when placed in the region of the socket, may contribute to avoid this unwanted reabsorption. Objective The objective of this study was to evaluate the distance of the crest of alveolar ridge to the cementoenamel junction (CEJ) of the lower second molars and the bone density of the third molar socket filled with Gen-Tech®, 5 years after an exodontia using cone beam computed tomography (CBCT) to visualize the central region of the sockets, without overlapping of the buccal and lingual cortical bones. Material and Methods A total of 12 individuals from an initial group of 39 patients submitted to extraction of the unruptured lower third molars and grafting of an association of inorganic bovine bone matrix, organic bovine bone matrix, collagen and bone morphogenetic proteins (BMP) (Gen-Tech®) on one side and the contralateral sockets filled only by clot, returned to control after 5 years, and were submitted to CBCT. The distance from the crest of alveolar bone to the CEJ and the bone density (BD) were measured using the i-CAT Vision Software. Results The results showed that the distance from the crest of alveolar bone to the CEJ in the control group was similar to that observed before the exodontia; in the experimental group, this distance was smaller. Considering the BD measurement, a significantly higher density was observed in the experimental group (p<0.05). Conclusion Part of the biomaterial was not absorbed and allowed the stability of the evaluated parameters after 5 years, being able to be used as a bone substitute in the socket.

Alveolar bone healing in rats: micro-CT, immunohistochemical and molecular analysis

Abstract Alveolar bone healing after upper incisor extraction in rats is a classical model of preclinical studies. The underlying morphometric, cellular and molecular mechanism, however, remains imprecise in a unique study. Objectives The aim of this study was therefore to characterize the alveolar bone healing after upper incisor extraction in rats by micro computed tomographic (Micro-CT), immunohistochemical and real-time polymerase chain reaction (RT-PCR) analysis. Material and Methods Thirty animals (Rattus norvegicus, Albinus Wistar) were divided into three groups after upper incisors extraction at 7, 14, and 28 days. Micro-CT was evaluated based on the morphometric parameters. Subsequently, the histological analyses and immunostaining of osteoprotegerin (OPG), receptor activator of nuclear kappa B ligand (RANKL) and tartrate resistant acid phosphate (TRAP) was performed. In addition, RT-PCR analyses of OPG, RANKL, the runt-related transcription factor 2 (RUNX2), osteocalcin (OC), osteopontin (OPN), osterix (OST) and receptor activator of nuclear kappa B (RANK) were performed to determine the expression of these proteins in the alveolar bone healing. Results Micro-CT: The morphometric parameters of bone volume and trabecular thickness progressively increased over time. Consequently, a gradual decrease in trabecular separation, trabecular space and total bone porosity was observed. Immunohistochemical: There were no differences statistically significant between the positive labeling for OPG, RANKL and TRAP in the different periods. RT-PCR: At 28 days, there was a significant increase in OPG expression, while RANKL expression and the RANKL/OPG ratio both decreased over time. Conclusion Micro-CT showed the newly formed bone had favorable morphometric characteristics of quality and quantity. Beyond the RUNX2, OC, OPN, OST, and RANK proteins expressed in the alveolar bone healing, OPG and RANKL activity showed to be essential for activation of basic multicellular units during the alveolar bone healing.

Hyaluronic acid accelerates bone repair in human dental sockets: a randomized triple-blind clinical trial

Abstract This study evaluated the effects of hyaluronic acid (HA) on bone repair of human dental sockets. Thirty-two lower first premolars were extracted from 16 patients (2 per patient) for orthodontic reasons. Following the extractions, one socket was randomly filled with 1% HA gel, while the other was allowed to naturally fill with blood clot. After 30 and 90 days of surgery, patients underwent cone beam computed tomography. Five central orthoradial slices were captured from each socket. The gray intensity was measured in each image and results were reported as mean percentage of bone formation. The buccolingual alveolar ridge width was measured and dimensional changes were compared between the postoperative intervals. The pattern of alveolar trabecular bone was evaluated through the fractal dimension. Treated sockets showed a higher percentage of bone formation and fractal dimension values (58.17% and 1.098, respectively) compared with controls (48.97% and 1.074, respectively) in the 30-day postoperative period (p < 0.05). After 90 days, there was no significant difference between groups. Additionally, no significant difference was found between groups regarding the alveolar dimensions (p > 0.05). Use of 1% HA gel after tooth extraction accelerates bone repair in human dental sockets.

Diagnosis of alveolar and root fractures: an in vitro study comparing CBCT imaging with periapical radiographs.

OBJECTIVE: To compare periapical radiograph (PR) and cone-beam computed tomography (CBCT) in the diagnosis of alveolar and root fractures. MATERIAL AND METHODS: Sixty incisor teeth (20 higid and 40 with root fracture) from dogs were inserted in 60 anterior alveolar sockets (40 higid and 20 with alveolar fracture) of 15 macerated canine maxillae. Each fractured socket had a root fractured tooth inserted in it. Afterwards, each maxilla was submitted to PR in two different vertical angulation incidences, and to CBCT imaging with a small field of view (FOV) and high-definition protocol. Images were randomized and posteriorly analyzed by two oral and maxillofacial radiologists two times, with a two-week interval between observations. RESULTS: Sensitivity and specificity values were good for root fractures for PR and CBCT. For alveolar fractures, sensitivity ranged from 0.10 to 0.90 for PR and from 0.50 to 0.65 for CBCT. Specificity for alveolar fractures showed lower results than for root fractures for PR and CBCT. Areas under the ROC curve showed good results for both PR and CBCT for root fractures. However, results were fair for both PR and CBCT for alveolar fractures. When submitted to repeated measures ANOVA tests, there was a statistically significant difference between PR and CBCT for root fractures. Root fracture intraobserver agreement ranged from 0.90 to 0.93, and alveolar fracture intraobserver agreement ranged from 0.30 to 0.57. Interobserver agreement results were substantial for root fractures and poor/fair for alveolar fractures (0.11 for PR and 0.30 for CBCT). CONCLUSION: Periapical radiograph with two different vertical angulations may be considered an accurate method to detect root fractures. However, PR showed poorer results than CBCT for the diagnosis of alveolar fractures. When no fractures are diagnosed in PR and the patient describes pain symptoms, the subsequent exam of choice is CBCT.