Academic literature on the topic 'Alveolar bone defect'

Objectives: The purpose of this study is to assess the effectiveness of mineralized plasmatic matrix in the soft tissue closure of naso-alveolar fistula, to estimate the postoperative bone fill and volume of the graft placed in the alveolar cleft defect using cone-beam computed tomography (CBCT) at 3rd- month and 6th- month. Material and methods: 10 patients, in the age group of 15‑30 years were included in this study. They were diagnosed with unilateral cleft lip and alveolus defects with or without a cleft palate requiring late secondary alveolar bone grafting. Alveolar cleft defects were closed with mineralized plasmatic matrix (MPM), a combination of autogenous iliac bone graft and platelet rich plasma (PRP) and platelet rich fibrin (PRF). Results: The mean defect volume pre-operatively is 0.75 cm3 and at the end of 3rd-month postoperatively is 0.51 cm3 and at 6th-month postoperatively is 0.27 cm3. The average percentage of bone fill between preoperative (A) & 3th- month postoperatively (B) is 33.4% and between 3rd-month (B) and 6th-month post operatively (C) is 49.5%. Conclusions: Utilization of this new matrix (MPM), has shown to be effective in the closure of the cleft defect, oro-nasal fistula and also reduction in the volume of the residual cleft defect seen with sequential cone-beam computed tomography (CBCT) radiographs.

In this study, hydroxyapatite coated vs uncoated implants were used to evaluate the type and dimensions of bone defects after progressive peri-implantitis in dogs. Thirty-two dental implants with 4 different surfaces—machined (M), sandblasted acid-etched (SA), 1-μm thin sputter hydroxyapatite (HA)-coated (S), and plasma-sprayed HA-coated (P)—were inserted into the mandibles of 4 beagle dogs after extracting all mandibular premolars. Experimental peri-implantitis was induced after 3 months using ligature to allow for plaque accumulation. After 4 months, ligatures were removed and plaque accumulation continued for 5 months (progression period). The open flap surgery demonstrated 3 patterns of peri-implantitis bone defect: (1) Class I defect: represented as circumferential intra-alveolar bone loss; (2) Class II defect: circumferential intra-alveolar defect with supra-alveolar bone loss exposing the implant surface; and (3) Class III defect: represented as circumferential intra-alveolar defect with supra-alveolar bone loss and buccal dehiscence. Class I was the most frequent (62.5%) defect pattern around implant types M, SA, and S; while implant type-P showed a recurring majority of Class II (62.5%). Comparison among the 4 implant groups revealed a significant defect width (DW) in implant type-P relative to other types (P < 0.01). However, no statistically significant differences were noted for defect depth (DD) (P > 0.05). We concluded that the shape and size of peri-implantitis bone defects were influenced by the type and thickness of the HA coat together with the quantity of the available peri-implant bone. Plasma-sprayed HA-coated implants showed larger peri-implant defects than did thin sputter HA-coated implants.

Calcitonin gene-related peptide (CGRP) is an important neuropeptide expressed in the nerve fibers during bone repair. Here, we aimed to pinpoint the role of CGRP in the osteogenic differentiation property of human periodontal ligament stem cells (hPDLSCs) and the resultant repair of alveolar bone defect. The key factor related to the osteogenic differentiation of hPDLSCs was retrieved from the GEO database. After extraction from hADSCs (hADSC-EVs) and identification, EVs were subjected to coculture with hPDLSCs, in which the expression patterns of CGRP and osteogenic differentiation marker proteins (ALP, RUNX2, and OCN), as well as ALP activity, were detected. A novel cell-free tissue-engineered bone (TEB) comprised of PLGA/pDA and hADSC-EVs was implanted into the rats with alveolar bone defects to evaluate the repair of alveolar bone defects. CGRP was enriched in hADSC-EVs. hADSCs delivered CGRP to hPDLSCs through EVs, thereby promoting the osteogenic differentiation potential of hPDLSCs. The PLGA/pDA-EV scaffold released EVs slowly, and its implantation into the rat alveolar bone defect area significantly induced bone defect repair, which was reversed by further knockdown of CGRP. In conclusion, our newly discovered cell-free system consisted of hADSC-EVs, and PLGA/pDA scaffold shows promising function in repairing alveolar bone defects.

Mesenchymal stem cells sheets have been verified as a promising non-scaffold strategy for bone regeneration. Alveolar bone marrow mesenchymal stem cells, derived from neural crest, have the character of easily obtained and strong multi-differential potential. However, the bone regenerative features of alveolar bone marrow mesenchymal stem cells sheets in the craniofacial region remain unclear. The purpose of the present study was to compare the osteogenic differentiation and bone defect repairment characteristics of bone marrow mesenchymal stem cells sheets derived from alveolar bone (alveolar bone marrow mesenchymal stem cells) and iliac bone (Lon-bone marrow mesenchymal stem cells) in vitro and in vivo. Histology character, osteogenic differentiation, and osteogenic gene expression of human alveolar bone marrow mesenchymal stem cells and Lon-bone marrow mesenchymal stem cells were compared in vitro. The cell sheets were implanted in rabbit calvarial defects to evaluate tissue regeneration characteristics. Integrated bioinformatics analysis was used to reveal the specific gene and pathways expression profile of alveolar bone marrow mesenchymal stem cells. Our results showed that alveolar bone marrow mesenchymal stem cells had higher osteogenic differentiation than Lon-bone marrow mesenchymal stem cells. Although no obvious differences were found in the histological structure, fibronectin and integrin β1 expression between them, alveolar-bone marrow mesenchymal stem cells sheet exhibited higher mineral deposition and expression levels of osteogenic marker genes. After being transplanted in the rabbit calvarial defects area, the results showed that greater bone volume and trabecular thickness regeneration were found in bone marrow mesenchymal stem cells sheet group compared to Lon-bone marrow mesenchymal stem cells group at both 4 weeks and 8 weeks. Finally, datasets of bone marrow mesenchymal stem cells versus Lon-bone marrow mesenchymal stem cells, and periodontal ligament mesenchymal stem cells (another neural crest derived mesenchymal stem cells) versus umbilical cord mesenchymal stem cells were analyzed. Total 71 differential genes were identified by overlap between the 2 datasets. Homeobox genes, such as LHX8, MKX, PAX9, MSX, and HOX, were identified as the most significantly changed and would be potential specific genes in neural crest mesenchymal stem cells. In conclusion, the Al-bone marrow mesenchymal stem cells sheet-based tissue regeneration appears to be a promising strategy for craniofacial defect repair in future clinical applications.

A precise volumetric assessment of maxillary alveolar defects in patients with cleft lip and palate can reduce donor site morbidity or allow accurate preparation of bone substitutes in future applications. However, there is a lack of agreement regarding the optimal volumetric technique to adopt. This study measured the alveolar bone defects by using two cone-beam computed tomography (CBCT)-based surgical simulation methods. Presurgical CBCT scans from 32 patients with unilateral or bilateral clefts undergoing alveolar bone graft surgery were analyzed. Two hands-on CBCT-based volumetric measurement methods were compared: the 3D real-scale printed model-based surgical method and the virtual surgical method. Different densities of CBCT were compared. Intra- and inter-examiner reliability was assessed. For patients with unilateral clefts, the average alveolar defect volumes were 1.09 ± 0.24 and 1.09 ± 0.25 mL (p > 0.05) for 3D printing- and virtual-based models, respectively; for patients with bilateral clefts, they were 2.05 ± 0.22 and 2.02 ± 0.27 mL (p > 0.05), respectively. Bland–Altman analysis revealed that the methods were equivalent for unilateral and bilateral alveolar cleft defect assessment. No significant differences or linear relationships were observed between adjacent different densities of CBCT for model production to obtain the measured volumes. Intra- and inter-examiner reliability was moderate to good (intraclass correlation coefficient (ICC) > 0.6) for all measurements. This study revealed that the volume of unilateral and bilateral alveolar cleft defects can be equally quantified by 3D-printed and virtual surgical simulation methods and provides alveolar defect-specific volumes which can serve as a reference for planning and execution of alveolar bone graft surgery.

Introduction: this study was conducted to investigate the osteogenic ability of periodontal ligament stem cells (PDLSCs) derived exosomes (PDLSCs-Exos) and the effect of PDLSCs-Exos with hydrogel on alveolar bone defect repairment in the rat. Methods: the PDLSCs were obtained through primary cell culture, and PDLSCs-Exos were purified by the ultracentrifugation method. The CCK-8 kit and ALP staining were used to explore the effect of PDLSCs-Exos on promoting the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). In vivo, the alveolar bone defect models were made mesial to the bilateral maxillary first molars of rats. MicroCT, HE staining, and Masson staining were used to analyze the new bone at the bone defect of rats. Results: the periodontal ligament stem cells and the periodontal ligament stem cells derived exosomes were successfully extracted. The results of the CCK-8 kit and ALP staining showed PDLSCs-Exos significantly promoted the proliferation osteogenic differentiation of BMSCs. In vivo experiment results revealed that compared with the control group and the hydrogel group, the rats in the hydrogel with exosomes group showed more new bone formation in alveolar bone defects. Conclusion: Periodontal ligament stem cells and exosomes derived from periodontal ligament stem cells were successfully extracted. The results demonstrated that the hydrogel successfully delivered periodontal ligament stem cells derived exosomes for repairing alveolar bone defects in rats in vivo at the initial stage.

Polyetheretherketone (PEEK) has the advantages of good biocompatibility, thus become a widely used bone remodeling material. Bioceramics are also highly effective bone repair materials. However, the repairing effect of biphasic bioceramics combined with polyetheretherketone composites on alveolar bone defects has not been elucidated. SD rats were separated into control group that was established as alveolar bone injury model; PEEK group that the alveolar bone injury model was repaired with polyether ether ketone; and composite group that alveolar bone injury model was repaired with double-tube biphase bioceramic/polyetheretherketone. After 8 weeks of treatment, the bone mineral density (BMD) changes were assessed by X-ray absorptiometry. HE staining was used to analyze the changes of tooth defect. The change of alkaline phosphatase (ALP) content was analyzed. Real-time PCR was performed to measure osteogenic factors Opn and Runx2 expressions. Serum BMP-2 level was analyzed by ELISA. The alveolar ridge height was compared and the alveolar bone repair rate was calculated. In the PEEK group and the composite group, BMD was significantly increased, bone was repaired, Runx2 and Opn mRNA expression was upregulated and ALP activity was enhanced along with elevated BMP-2 secretion, alveolar ridge height and bone repair rate compared to control group (P < 0 05). The composite group exhibited more significant changes compared with PEEK group (P < 0 05). Double-tube biphasic bioceramic/polyetheretherketone composites can repair alveolar bone defects, promote osteogenic differentiation, induce BMP-2 secretion, enhance bone density, and accelerate alveolar bone repair.

Abstract Extensive bone defects complicate the adequate placement of dental implants and the required angulation. In such cases, alveolar-ridge augmentation techniques such as guided bone regeneration, particulate or block grafting, and alveolar bone distraction are needed. The present study describes a case in which a large vertical bone defect in the anterior mandibular zone was corrected via vertical alveolar bone distraction. Six dental implants were posteriorly placed for implant-supported restoration of the mandible, with early implant loading. The clinical and radiologic control showed good implant and soft tissue conditions 12 months later.

Objective: To assess the radiographic outcome of secondary alveolar bone grafting in individuals with nonsyndromic unilateral or bilateral cleft lip and palate using cone beam computed tomography. Methods: This prospective study was conducted at the University of California at San Francisco Center for Craniofacial Anomalies on 21 consecutive nonsyndromic complete cleft lip and palate individuals between 8 and 12 years of age who required alveolar bone grafting. Seventeen unilateral and four bilateral cleft lip and palate individuals had preoperative and postoperative cone beam computed tomography scans that were analyzed using Amira 3.1.1 software. Results: The average volume of the preoperative alveolar cleft defect in unilateral cleft lip and palate was 0.61 cm3, and the combined average volume of the right and left alveolar cleft defects in bilateral cleft lip and palate was 0.82 cm3. The average percentage bone fill in both unilateral cleft lip and palate and bilateral cleft lip and palate was 84%. The outcome of alveolar bone grafting was assessed in relation to (1) type of cleft, (2) size of preoperative cleft defect, (3) presence or absence of lateral incisor, (4) root development stage of the maxillary canine on the cleft side, (5) timing, and (6) surgeon. None of these parameters significantly influenced the radiographic outcome of alveolar bone grafting. Conclusions: Secondary alveolar bone grafting of the cleft defect in our center was successful, based on radiographic outcome using cone beam computed tomography scans. Volume rendering using cone beam computed tomography and Amira software is a reproducible and practical method to assess the preoperative alveolar cleft volume and the adequacy of bone fill postoperatively.

In this study, we fabricated gelatin/nano-hydroxyapatite/metformin scaffold (GHMS) and compared its effectiveness in bone regeneration with extraction-only, Sinbone, and Bio-Oss Collagen® groups in a critical size rat alveolar bone defect model. GHMS was synthesized by co-precipitating calcium hydroxide and orthophosphoric acid within gelatin solution, incorporating metformin, and cross-linked by microbial transglutaminase. The morphology, characterization, and biocompatibility of scaffold were examined. The in vitro effects of GHMS on osteogenic gene and protein expressions were evaluated. In vivo bone formation was assessed in a critical size rat alveolar bone defect model with micro-computed tomography and histological examination by comparing GHMS with extraction-only, Sinbone, and Bio-Oss Collagen®. The synthesized GHMS had a highly interconnected porous structure with a mean pore size of 81.85 ± 13.8 µm. GHMS exhibited good biocompatibility; promoted ALPL, RUNX2, SP7, BGLAP, SPARC and Col1a1 gene expressions; and upregulated the synthesis of osteogenic proteins, including osteonectin, osteocalcin, and collagen type I. In critical size rat alveolar bone defects, GHMS showed superior bone regeneration compared to extraction-only, Sinbone, and Bio-Oss Collagen® groups as manifested by greater alveolar ridge preservation, while more bone formation with a lower percentage of connective tissue and residual scaffold at the defect sites grafted with GHMS in histological staining. The GHMS presented in this study may be used as a potential bone substitute to regenerate alveolar bone. The good biocompatibility, relatively fast degradation, interconnected pores allowing vascularization, and higher bioactivity properties of the components of the GHMS (gelatin, nHA, and metformin) may contribute to direct osteogenesis.

INTRODUCTION During the three-year doctoral period, the candidate developed 3 research projects which, although different, are all related to one of the most controversial topics of advanced implant dentistry which include procedures to make it possible the use of dental implants also in case of severely atrophic edentulous ridges. During the last decade, a variety of surgical procedures have been proposed, each of them with specific indications, contraindications, advantages and disadvantages. Despite the publication of numerous systematic reviews and meta-analyses focused on this fascinating topic, much controversy is still present between clinicians and researches. The aims of the PhD candidate have been to focus on three main areas related to the correction of severely atrophic edentulous ridges in order to: 1) update the present knowledge on this particular field thank to a systematic analysis of the available literature; and 2) develop three different research projects specifically dedicated to regeneration/reconstruction procedures. More in detail, one line of research was focused on the evaluation of medium to long-term results of dental implants placed in severely atrophic jaws reconstructed with autogenous calvarial bone blocks covered with bovine bone mineral and collagen membranes. Seventy-two patients and 330 implants were involved in this retrospective study with a mean follow-up after implant loading of 8 years, ranging from 3 to 19 years. The second project, similar in structure to the previous one, was designed to evaluate retrospectively the medium and long-term results (with a mean follow-up of 10 years) of implants placed in atrophic edentulous ridges grafted with autogenous mandibular blocks covered with bovine bone mineral and collagen membranes. Seventy-five patients, 82 sites, and 182 implants were involved in this study. The third line of research allowed the candidate to design a prospective study which involved edentulous and atrophic patients treated with guided bone regeneration using CAD-CAM customized titanium meshes. The effectiveness of digitally customized titanium meshes in association with autologous bone particles and bovine bone mineral for the regeneration of atrophic edentulous sites, and the survival rate of implants placed in the reconstructed areas were evaluated. A histomorphometric analysis of mandibular regenerated bone were also performed. Forty-one patients, 53 sites, and 106 implants were involved in this study and the follow-up of implants before and after loading ranged from 2 to 23 months (mean: 11 months), and from 1 to 15 months (mean: 6 months), respectively. This latter research is of particular interest, as the literature supporting this particular technique is scarce, and available data are difficult to be compared, because they have been collected in a non- systematic way and mainly retrospectively. In all these studies, a dedicated questionnaire, adapted from the OHIP-14 survey, was performed to evaluate patients’ satisfaction (patient reported outcome measurements – PROMs) as regards the treatment received. It was therefore possible to elaborate a discussion of the results on two different levels: the first associated to the specific regenerative / reconstructive technique; the second allowed a comparison among the different treatment solutions. AIMS The aim of the first and second project, two retrospective longitudinal cohort studies, is to present the medium to long-term outcome of bone reconstructions with calvarium or mandibular grafts , respectively by evaluating: a) complication rate of the reconstructive procedure; b) bone resorption before implant placement; c) peri-implant bone resorption; d) implant-related complications; e) implant survival rate; and, f) patient’s satisfaction inquired with a dedicated questionnaire. The aims of the third project, a prospective, single-arm clinical study, are to evaluate: a) the effectiveness of digitally customized titanium meshes in association with autologous bone particles and BBM and covered with collagen membranes for the regeneration of atrophic edentulous sites; b) the survival rate of implants placed in the regenerated areas and, c) PROMs inquired with a dedicated questionnaire. MATERIALS & METHODS Project 1 – calvarium From 1998 to 2014, 72 patients presenting with severe bone defects were reconstructed with autogenous calvarial bone blocks covered with bovine bone mineral granules and collagen membranes. Four to 9 months later, 330 implants were placed and loaded 3 to 9 months later. The follow-up ranged from 3 to 19 years (mean: 8.1 years). Project 2 – ramus from 1997 to 2015, 75 patients presenting with bone defects of the jaws were grafted with autogenous mandibular bone blocks. One-hundred-eighty-two implants were placed 4 to 12 months later and loaded 3 to 10 months later: the mean follow-up was 10 years (range: 3-16 years). Project 3 – GBR with Ti-mesh 41 patients, presenting with 53 atrophic sites were enrolled between 2018 and 2019. GBR was obtained with titanium meshes filled with autogenous bone chips and bovine bone mineral (BBM). After a mean of 7 months (range: 5-12 months), meshes were removed and 106 implants placed. After a mean of 3.5 months (range: 2-5 months), implants were uncovered and prosthetic restorations started. RESULTS Project 1 – calvarium No patients developed severe complications, such as complete loss or resorption of the grafts. A dehiscence occurred in 6 patients, which developed a mild graft resorption. The mean peri-implant bone resorption before implant placement was 0.13 mm (SD ± 0.71). All patients received the planned number of implants. Three patients were lost during the follow-up. The survival rate of implants at the end of the observation period was 98.5%. The mean peri-implant bone resorption ranged from 0.00 mm to 4.87 mm (mean: 1.11 mm). Finally, 90% of the patients were very satisfied as regards the treatment received. Project 2 – ramus Post-operative recovery was uneventful in the majority of patients. An early dehiscence occurred in three patients, but with no significant bone loss, while 3 experienced temporary paresthesia. The mean vertical and horizontal bone resorption before implant placement was 0.18 mm (standard deviation (SD)=0.43) and 0.15 mm (SD=0.42), respectively. The mean peri-implant bone loss ± standard deviation was 1.06±1.19 (range 0.00 to 5.05) at patient level, and 1.11±1.26 (range 0.00 to 5.20) at implant level. Two implants in 2 patients lost integration and were removed; 10 implants in 7 patients developed peri-implantitis, but healed after surgical treatment. The cumulative implant survival and success rates were 98.11% and 85.16%, respectively. PROMs were very positive: 95.5% of patients would have undergone the procedure again. Project 3 – GBR with Ti-mesh out of 53 sites, 11 underwent mesh exposure: 8 of them were followed by uneventful integration of the graft, while 3 by partial bone loss. The mean vertical and horizontal bone gain after reconstruction was 4.78±1.88mm (range 1.00 to 8.90mm), and 6.35±2.10mm (range 2.14 to 11.48 mm), respectively. At the time of implant placement, mean changes of initial bone gain were -0.39±0.64mm (range -3.1 to +0.80mm), and -0.49±0.83mm (range –3.7 to +0.4mm), in the vertical and horizontal dimensions, respectively. Reduction of bone volume was significantly higher (P<0.001 for both dimensions) in the exposed sites. At histologic analysis, mesh appeared well osseointegrated, except that in sites where membrane exposure occurred. In all sites, newly formed tissue resulted highly mineralized, well-organized and formed by 35.88% of new lamellar bone, 16.42% of woven bone, 10.88% of osteoid matrix, 14.10% of grafted remnants and 22.72% of medullary spaces. Blood vessels were the 4 % of the tissue.The mean follow-up of implants after loading was 10.6±6.5months (range: 2 to 26months). The survival rate of implants was 100%. PROMs were very positive: 92.5% of patients would have undergone the procedure again. DISCUSSION These three projects have offered, on one side, a relevant opportunity to evaluate the short, medium, and long-term outcomes of both reconstructions with autogenous bone blocks and guided bone regeneration with an innovative, customized, titanium mesh. On the other side, “intrinsic” methodologic limits have appeared during the development of this PhD thesis, such as: o heterogeneity of patient samples and type of defects; o retrospective and prospective type of study; o duration of the observation period; o presence/absence of evaluation of bone gain and with different methods; o different methods used to evaluate bone resorption before implant placement. Despite these limits, results from these three researches offered relevant information as regards the behaviour of the transplanted /regenerated bone as well as the behaviour of peri-implant bone over time. Although the three projects significantly differ among them as regards details in the reconstructive procedures, it must be underlined that many aspects are in common. Therefore, to reduce redundancies it has been decided to write a “unified” discussion which will make it possible a direct comparison of pros, cons, indications and contra-indications of each of them. More in detail, each of the following issues will be discussed reporting and comparing obtained from each study: 1. bone gain; 2. complication rate of the reconstructive procedure; 3. bone resorption before implant placement; 4. peri-implant bone resorption; 5. survival rate of implants and implant-related complications; 6. patient’s satisfaction inquired with a dedicated questionnaire. CONCLUSION Despite the descriptive nature of the first two retrospective longitudinal cohort studies and the variability of the selected patients (including different patients anamnesis, defects locations, defect morphologies, and prosthetic rehabilitations), medium- to long-term results seem to confirm the efficacy of reconstruction of atrophic ridges using autogenous bone blocks taken from both the calvarium and the mandibular ramus covered by a protective layer of bovine bone mineral and stabilized by a collagen membrane. The use of autogenous calvarial grafts may be prefer in case of severely deficient edentulous ridges, when the ramus can offer an insufficient quantity of bone. The low postoperative morbidity, the stability over time of the augmented bone, the high survival rate of implants placed in a prosthetically driven way, leading to very satisfactory prosthetic restorations, confirmed the long-term reliability of these procedures. Preliminary results of the third prospective study, on the other hand, despite the limited number of patients, implants, short follow-up, and the non-negligible incidence of Ti-mesh exposures, seem to demonstrate that CAD-CAM customized Ti-meshes may represent a reliable GBR option for the correction severely atrophic edentulous ridges in terms of vertical bone gain, limited peri-implant bone resorption and survival rate of implants. It is however worth noting that if on one hand it is possible to simplify the reconstructive procedure thanks to the customization of Ti-meshes, on the other hand surgeons have to face the non-negligible incidence of Ti-mesh exposures and the higher complexity of their removal at the time of implant placement. Therefore, studies involving a higher sample of patients and with longer follow-ups are necessary. PROMs seem to validate the use of all the regenerative and reconstructive procedures, with high value of patient’ satisfaction.

Peri implant and periapical bone defects are widespread in the world population. Considering the high number of implant placement and root canal treatment performed every year, resolution of these bone defects will be of predominant interest in the next future. The present project has several aims: The first part of the project aimed to investigate how and what factors affect peri implant bone remodeling process. Microchemical analysis of the peri implant bone interface of retrieved human dental implants was performed. In addition, prospective clinical studies were conducted to evaluate the factors mostly related to peri implant bone loss. The second part of the project aimed to evaluate chemical physical and micromorphological properties of hydraulic calcium silicates based materials (CaSi), which gained a particular attention in the endodontic field. Use of these materials claimed to resolve several complex endodontic complications, however few information is present in literature. These materials were compared with some “gold standard” bioinert materials. Given the attractive biointeractive properties of CaSi based materials, the last part of the study will focus on the design and characterization of new mineral based scaffolds, aimed to be applied in future bone regeneration procedures. Scaffolds, composed of a polymeric matrix were doped with CaSi and calcium phosphates, in order to increase the materials biointeractive properties. A complete characterization of their chemical-physical-mechanical-thermal properties was performed, as well as the evaluation of apatite forming ability (bioactivity) and biocompatibility of these mineral based scaffolds. The combination of Human Periapical-cysts Mesenchymal Stem Cells (hPC-MSC) as a potential strategy to achieve periapical bone regeneration was evaluated. Finally, the angiogenesis potential of these scaffolds was investigated through the growth and proliferation of porcine vascular wall mesenchymal stem cells (pvw-MSC) was performed.

Objetivo: O propósito deste estudo é avaliar a regeneração óssea nos defeitos alveolares congênitos com proteína morfogenética óssea (rhBMP-2) em membrana de colágeno reabsorvível. Material e Métodos: Vinte e quatro pacientes com fissura labiopalatina completa unilateral, em momento ideal, foram distribuídos ao acaso entre os grupos controle (porção medular de ilíaco) e teste (rhBMP-2 em membrana de colágeno absorvível). Foram avaliados em 6 meses e 1 ano de pós-operatório por meio de radiografias periapicais e tomografias computadorizadas pela escala de Chelsea. Resultados: Encontraram-se índices de sucesso quanto à altura do septo ósseo semelhantes entre os grupos: em 6 meses, na análise radiográfica, 81,82% no controle e 91,67% no teste; em 1ano, 83,33% no controle e 100% no teste; na análise tomográfica, observaram-se 70% no controle e 91,67% no teste em 6 meses, 75% no controle e 100% no teste em 1 ano. Na análise volumétrica, os valores encontrados foram 45,34% de preenchimento ósseo da fissura no grupo controle aos 6 meses e 40,63% no teste, 53,33% no controle e 53,1% no teste em 1 ano. Não houve diferença estatisticamente significante. Conclusão: A rhBMP-2 em membrana reabsorvível de colágeno produziu resultados semelhantes ao enxerto autógeno de medula de crista ilíaca ao reparar defeitos alveolares de fissuras labiopalatinas completas.
Objective: The purpose of this study is to assess the bony regeneration of alveolar clefts using bone morphogenetic protein (rhBMP-2) in a collagen sponge carrier. Material and Methods: Twenty four patients with unilateral complete cleft lip and palate, in the very best moment, were randomly assigned to groups control (iliac crest cancellous bone) and test (rhBMP-2 in an absorbable collagen sponge). They were evaluated 6 months and 1 year postoperative with periapical radiographs and computed tomographs using Chelsea scale. Results: For control group, radiographic examination revealed success index for bone height 81,82% 6 months and 83,33% 1 year postoperative; for test group, findings were 91,67% first control and 100% 1 year. Computed tomograph revealed 70% 6 months and 75% 1 year for control group, 91,67% first control and 100% 1 year for bone height test group. Volume ratios were 45,34% bone filling 6 months and 53,33% 1 year for control group and 40,63% 6 months and 53,1% 1 year for test. There was no statistical significance. Conclusion: rhBMP-2 in a collagen sponge carrier induced bony regeneration close to that from iliac crest cancellous bone to repair complete alveolar clefts.

Proposição: avaliar radiograficamente e histologicamente o comportamento do incisivo inferior de rato frente à realização de uma solução de continuidade em sua porção radicular mediana quanto ao comportamento do tecido pulpar e dos enxertos ósseos alógenos congelados à -80°C e a evolução do seu processo eruptivo dentário em alvéolos quando expostos aos efeitos da ação do ultra-som. Metodologia: estudo experimental in vivo, amostragem randomizada, com um grupo teste e outro controle. Constou de 29 ratos, da espécie Rattus novergicus albinus, linhagem Wistar, machos, divididos em quatro grupos, correspondendo aos tempos de sete, 14, 21 e 45 dias. Em cada grupo, cinco animais foram teste e dois animais foram controle. Em cada animal foi removido, cirurgicamente, o segmento medial do incisivo inferior direito. Entretanto, nos animais do grupo experimental foram realizados enxertos de osso alógeno congelado a -80°C, nos 2,0mm distais do total da cavidade alveolar cirurgicamente obtida com ultra-som.Resultados: aos sete dias observou-se estrutura tecidual desorganizada e ricamente vascularizada em ambos os grupos avaliados e início da integração do enxerto ósseo no grupo teste. Aos 14 dias seguem as mesmas observações descritas aos sete dias com progressão da incorporação do enxerto ósseo. Aos 21 dias, observa-se intensa neoformação óssea, ricamente vascularizada em ambos grupos. Aos 45 dias, existe também uma intensa neoformação óssea alveolar, fechando o alvéolo e a completa integração dos enxertos ósseos. Em todos os grupos observou-se que houve mínimo crescimento do segmento dentário proximal e que o mesmo manteve sua vitalidade pulpar. Conclusão: Após a realização deste estudo foi possível concluir que: o tecido pulpar, contido no segmento proximal manteve sua vitalidade, reagindo na forma de reparação dentinária compatível com o dente humano; o enxerto ósseo alógeno congelado evolui favoravelmente no processo de incorporação a partir de um leito receptor criado no alvéolo dentário e que o incisivo inferior do rato, submetido à odontossecção com ultra-som não seguiu com o processo de crescimento e erupção em seu segmento proximal, podendo estar relacionado com o reparo do alvéolo devido à intensa neoformação óssea, provavelmente por efeito do ultra-som.
Proposition: This study aimed to evaluate, both radiographically and histologically, the behaviour of a rat’s inferior incisive concerning the realization of a continuous solution in its medial radicular portion, regarding the behaviour of the pulpal tissue and allogeneic freezing bone grafts, at –80° C, as well as the evolution in its dental eruptive process in alveoli exposed to ultrasound effects. Methodology: An in vivo experimental study, using randomized samples, including a study group and a control group. Twenty-nine Wistar strain male rats, Rattus novergicus albinus species, divided into 4 groups, corresponding to 7, 14, 21, and 45 days. From each group, five animals were considered as the test group, and two of them as the control group. Each animal had the medial segment of the right inferior incisive surgically removed. However, the animals from the test group underwent allogeneic freezing bone grafts, at –80° C, in a range of 2.0 mm distal of the total alveolar cavity, surgically performed by ultrasound. Results: In seven days a disorganized and well-vascularized tissue structure in both assessment groups as well as the beginning of the integration of the bone graft in the experimental group could be observed. In 14 days similar observations to day 7 and progression in the incorporation of the bone graft were found. In 21 days intense, well-vascularized, bone neoformation was observed in both groups. In 45 days an intense neoformation of the alveolar bone could also be observed, with the closure of the alveolus, and the complete integration of the bone grafts. All groups had a minimum growth of the dental proximal segment, which maintained its pulpal vitality. Conclusion: The study concluded that the pulpal tissue contained in the proximal segment maintained its vitality, providing a reaction compatible with human tooth regarding dental repairing. The allogeneic freezing bone graft evolved favorably in the incorporation process from a receiver layer created inside the dental alveolus. It was also concluded the rat’s inferior incisive which underwent ultrasonic dental cutting did not follow the growth and eruption process in its proximal segment, what might be related to the alveolus repair due to intense bone neoformation, probably caused by the ultrasound effect.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Proposição: A proposta deste estudo foi avaliar por análise histométrica a resposta tecidual óssea de enxerto autógeno coletado por piezocirurgia para o preenchimento de defeitos nas porções cervicais de implantes instalados em tíbias de coelhos. Métodos: Foram instalados 26 implantes em 13 tíbias de coelho, após a estabilidade inicial foram realizados defeitos cervicais por trefinagem, em um grupo foi mantido apenas o coágulo como preenchimento e em outro grupo o defeito foi preenchido por osso autógeno coletado por equipamento piezoelétrico, os animais foram sacrificados após 15 e 30 dias, a análise histométrica das interfaces implante-osso foram realizadas pelo software Image Lab. Resultados: Foi analisado o percentual de extensão linear de contato entre tecido ósseo e implante, a média percentual obtida de contato entre tecido ósseo neoformado e implante foram estabelecidas como médias da área de osso neoformado entre as espiras e contato osso-implante (BIC). Os resultados obtidos foram: no controle de 15 dias, o percentual entre as espiras foi de 65,2% e entre as espiras e contato osso-implante (BIC) de 88,7%. No controle de 30 dias o contato entre as espiras foi na ordem de 65,2% e entre as espiras e contato osso-implante (BIC) de 73,2%. No grupo de enxerto de 15 dias, o osso formado entre as espiras foi de 69,3% e entre as espiras e contato osso-implante (BIC) em 81%, no grupo enxerto 30 dias o osso formado entre as espiras foi de 91,47% e entre as espiras e contato ossoimplante (BIC) 91,56%. Conclusão: o enxerto ósseo autógeno particulado obtido por piezocirurgia apresenta melhor resultado que o coágulo sanguíneo no osso neoformado entre as espiras e no contato osso-implante
Purpose: The purpose of this study was to evaluate by histometric analysis the outcome of autogenous bone collected through piezo surgery equipment in filling cervical portion defects around implants placed in rabbits tibias. Materials and Methods: Twenty-six implants were installed in 13 rabbits tibias, after initial primary stability, cervical defects were carried out by the use of a trephina, in one group the cloth was maintained as the defect filling and in another group the defect was filled by autogenous bone collected through piezo surgery equipment, the animals were sacrificed after 15 and 30 days, the histometric analysis of the implant-bone interfaces were carried out by the use of Image Lab software. Results: The lineal stretch percentage of contact between bone and implant was analyzed, the average percentage obtained in the contact between the newly formed bone and the implant was established as the average area of the newly formed bone in the space between the spires and the bone-implant contact (BIC). The results obtained were: in the 15-days control group, the percentage of bone formation between the spires was of 65.2% and between the spires and boneimplant contact (BIC) was of 88.7%. In the 30-days control group the contact between the spires was of 65.2% and between the spires and bone-implant contact (BIC) of 73.2%. In the 15-days control grafted group, the formed bone between the spires was of 69.3% and between the spires and bone-implant contact (BIC) of 81%, in the 30-days control grafted group, the formed bone between the spires was of 91.47% and between the spires and bone-implant contact (BIC) of 91.56%. Conclusions: the autogenous bone collected through piezo surgery equipment showed better results than the blood clot regarding the newly formed bone between the spires and bone-implant contact (BIC)

Orientador: Idelmo Rangel Garcia Júnior
Banca: Élio Hitoshi Shinohara
Banca: Thallita Pereira Queiroz
Banca: Jéssica Lemos Gulinelli
Banca: Martha Alayde Alcantara Salim
Resumo: Proposição: A proposta deste estudo foi avaliar por análise histométrica a resposta tecidual óssea de enxerto autógeno coletado por piezocirurgia para o preenchimento de defeitos nas porções cervicais de implantes instalados em tíbias de coelhos. Métodos: Foram instalados 26 implantes em 13 tíbias de coelho, após a estabilidade inicial foram realizados defeitos cervicais por trefinagem, em um grupo foi mantido apenas o coágulo como preenchimento e em outro grupo o defeito foi preenchido por osso autógeno coletado por equipamento piezoelétrico, os animais foram sacrificados após 15 e 30 dias, a análise histométrica das interfaces implante-osso foram realizadas pelo software Image Lab. Resultados: Foi analisado o percentual de extensão linear de contato entre tecido ósseo e implante, a média percentual obtida de contato entre tecido ósseo neoformado e implante foram estabelecidas como médias da área de osso neoformado entre as espiras e contato osso-implante (BIC). Os resultados obtidos foram: no controle de 15 dias, o percentual entre as espiras foi de 65,2% e entre as espiras e contato osso-implante (BIC) de 88,7%. No controle de 30 dias o contato entre as espiras foi na ordem de 65,2% e entre as espiras e contato osso-implante (BIC) de 73,2%. No grupo de enxerto de 15 dias, o osso formado entre as espiras foi de 69,3% e entre as espiras e contato osso-implante (BIC) em 81%, no grupo enxerto 30 dias o osso formado entre as espiras foi de 91,47% e entre as espiras e contato ossoimplante (BIC) 91,56%. Conclusão: o enxerto ósseo autógeno particulado obtido por piezocirurgia apresenta melhor resultado que o coágulo sanguíneo no osso neoformado entre as espiras e no contato osso-implante
Abstract: Purpose: The purpose of this study was to evaluate by histometric analysis the outcome of autogenous bone collected through piezo surgery equipment in filling cervical portion defects around implants placed in rabbits tibias. Materials and Methods: Twenty-six implants were installed in 13 rabbits tibias, after initial primary stability, cervical defects were carried out by the use of a trephina, in one group the cloth was maintained as the defect filling and in another group the defect was filled by autogenous bone collected through piezo surgery equipment, the animals were sacrificed after 15 and 30 days, the histometric analysis of the implant-bone interfaces were carried out by the use of Image Lab software. Results: The lineal stretch percentage of contact between bone and implant was analyzed, the average percentage obtained in the contact between the newly formed bone and the implant was established as the average area of the newly formed bone in the space between the spires and the bone-implant contact (BIC). The results obtained were: in the 15-days control group, the percentage of bone formation between the spires was of 65.2% and between the spires and boneimplant contact (BIC) was of 88.7%. In the 30-days control group the contact between the spires was of 65.2% and between the spires and bone-implant contact (BIC) of 73.2%. In the 15-days control grafted group, the formed bone between the spires was of 69.3% and between the spires and bone-implant contact (BIC) of 81%, in the 30-days control grafted group, the formed bone between the spires was of 91.47% and between the spires and bone-implant contact (BIC) of 91.56%. Conclusions: the autogenous bone collected through piezo surgery equipment showed better results than the blood clot regarding the newly formed bone between the spires and bone-implant contact (BIC)
Doutor

Introdução A abordagem do estudo dos recursos imaginológicos aplicados à análise óssea diz respeito ao estudo topográfico do periodonto e suas alterações. Consiste em avaliar a contribuição dos referidos recursos em razão das limitações dos exames convencionais. Objetivo Analisar por meio de dois sistemas de imagens digitais: a radiografia digital direta e a tomografia computadorizada por feixe cônico, comparando a eficácia de cada aparelho na análise das corticais do tecido periodontal e suas alterações. Métodos Cinco espécimes de mandíbulas foram incluídos em nosso estudo, com 6 tipos de defeitos ósseos distribuídos no septo interdentário e na porção radicular do dente. Radiografias periapicais foram realizadas, com o sensor sensor Dixi®2 (Planmeca Oy, Helsinki, Finlândia), e exames tomográficos, com o aparelho Newtom 3G (QR Srl, Verona, Itália). A pesquisa qualitativa, de caráter subjetivo, contemplou a análise das corticais ósseas avaliadas por três observadores em um total de 40 sítios para cada modalidade de exame. Teste estatístico de McNemar foi empregado para análise inter e intraobservadores. Resultados Resultados não concordantes foram relacionados à sobreposição de estruturas anatômicas em sua maior parte pela radiografia digital direta. Os resultados de acerto da tomografia computadorizada por feixe cônico: para análise da cortical vestibular do septo interdentário foi de 84%; para a cortical lingual de 92%; para a cortical proximal de 80%; e para cortical radicular de 80%, contra 60%, 64%, 80% e 46% respectivamente da radiografia digital. Não foram encontradas diferenças entre a 1ª e a 2ª análises na avaliação intra-observadores, contudo houve variação inter-observadores. Conclusões A tomografia computadorizada por feixe cônico mostrou-se como potencial recurso de imagem para análise das corticais ósseas do tecido periodontal. Entretanto, os resultados também apontaram que ambos os métodos são observador-dependentes, havendo necessidade de profissionais habilitados para utilização desses recursos recentes de imagem. Também avaliamos que estudos adicionais deveriam ser aplicados para maior entendimento do assunto estudado.
Introduction The study of the imaging resources applied to bone analysis regards to the topographic study of the periodontium and its changes. It is an assessment of the contribution of the related resources as compared to the limitations of conventional exams. Objective To analyze two digital imaging systems: the direct digital radiography and the cone beam computed tomography, comparing the efficacy of each device to analyze the cortical plates of the periodontal tissue and its changes. Methods Five mandible specimens were included in our study, with 6 types of bone defects distributed on the interdental septum and on the radicular portion of the tooth. Periapical radiographs with the Dixi®2 sensor (Planmeca Oy, Helsinki, Finland) and tomographic scans with Newtom 3G device (QR Srl, Verona, Italy) were obtained. The qualitative research, with a subjective feature, included the analysis of the bone cortical plates for a total of 40 sites with each examination method carried out by three observers. The McNemar statistic test was used for inter and intraobserver analyses. Results Results which did not agree were related to the overlay of anatomic structures mainly due to the direct digital radiography. The correct results for cone beam computed tomography were: 84% for the analysis of vestibular cortical plate of the interdental septum; 92% for lingual cortical plate; 80% for proximal cortical plate; and 80% for radicular cortical plate, against 60%, 64%, 80% e 46%, respectively, with digital radiography. No differences were found between the 1st and 2nd intraobserver analyses, but there was interobserver variation. Conclusion The cone beam computed tomography was shown to be a potential imaging resource for the analysis of the bone cortical plates of the periodontal tissue. However, the results also showed that both methods are observer-dependent, and there is a need for skilled professionals to use this recent imaging technology. In addition, we considered the additional studies that should be applied to improve the understanding of this subject.

In dental debilitating conditions, such as edentulism, the patient must have sufficient alveolar crest bone mass to guarantee the possibility of corrective interventions, such as implants. The decrease in bone tissue is caused by the body's natural reabsorption, which begins after tooth loss. Some surgical techniques could be used to solve this problem, such as guided bone regeneration. In this technique, a membrane developed with biomaterials is used, which aims to act as physical barrier to prevent the appearance of soft tissue and maintain the bone defect space, ensuring maximum regeneration. This membrane must be biocompatible, have specific rigidity to maintain the space, prevent the migration of epithelial cells and ensure the resorption time after bone tissue regeneration. This chapter will address the polymeric materials most used in the development of membranes for guided bone regeneration process, addressing their physicochemical characteristics, advantages, disadvantages, among other important aspects.

Implant supported restorations have become an ideal treatment alternative for the rehabilitation of edentulous sites. However alveolar bone defects due to resorption, trauma or oncologic diseases may considerably affect favorable implant positioning and prosthetic outcomes. Various alveolar ridge augmentation procedures are available to gain enough bone volume and apply the ideal treatment plan afterwards. Guided bone regeneration, ridge splitting, distraction osteogenesis, maxillary sinus augmentation and autogenous block bone grafting are main techniques which have successful outcomes in reconstruction of bone defects. It’s difficult to demonstrate that one augmentation procedure offers better outcomes than another. Studies documenting augmentation techniques seem to be comparable and state favorable results for each procedure.

Advanced therapies hold substantial promise for the treatment of periodontal conditions. Gene therapy has the potential to transfer “therapeutic” genes, which express proteins such as bone morphogenetic proteins, osteoprotegerin, and tissue nonspecific alkaline phosphatase, which is deficient in patients with hypophosphatasia, a condition that affects mineralization of teeth and bone. Transferred genes may also express platelet-derived growth factor, which modulates the growth of periodontal tissue and the alveolar bone. As regards cell therapy, several clinical trials have shown that mesenchymal stem cells, when used with different kinds of scaffolds to enable the required three-dimensional environment, possess a bone regeneration potential that is particularly useful in such disorders as osteoporosis and osteonecrosis, or for regenerating alveolar bone (osseointegration) prior to placing a dental implant. However, much work is still required before these new therapies become true alternatives in routine clinical dental practice. Medical advances require investments, which are usually influenced by the priorities of both politicians and society at large. This will contribute to promoting innovation, efficient treatments, medium- and long-term savings, and a higher quality of life.

Missing a permanent tooth is a miserable condition faced by a common man. A tooth decay, periodontitis, mechanical trauma, or any systemic complications lead to such a complication. These bone defects when left untreated lead to severe resorption of the alveolar bone. A proper dental filling with an appropriate bone substitute material could prevent such resorption and paves a way for subsequent implant placement. Dental implants are considered as the prime option by dentists to replace a single tooth or prevent bone resorption. A variety of bone substitutes are available differ in origin, consistency, particle size, porosity, and resorption characteristics. Herbal composites in dentistry fabricated using biphospho-calcium phosphate, casein, chitosan, and certain herbal extracts of Cassia occidentalis, Terminalia arjuna bark, Myristica fragans also were reported to possess a higher ossification property, osteogenic property and were able to repair bone defects. C. occidentalis was reported to stimulate mineralization of the bone and osteoblastic differentiation through the activation of the PI3K-Akt/MAPKs pathway in MC3T3-E1 cells of mice. This implant proved better osteoconductivity and bioactivity compared to pure HAP and other BCP ratios. Terminalia Arjuna was also worked in the incorporation in the graft to enhance the osteogenic property of the implant and gave good results. Another implant bone graft was synthesized containing BCP, biocompatible casein, and the extracts of Myristica fragans and subjected to in vitro investigations and the results revealed the deposition of apatite on the graft after immersing in SBF and also the ALP activity was high when treated with MG-63 cells, NIH-3 T3, and Saos 2 cell lines. This study indicates that the inclusion of plant extract enhances the osteogenic property of the graft. Thus, these novel dental implants incorporated with herbal composites evaluated by researchers revealed an enhanced bone healing, accelerates osseointegration, inhibits osteopenia, and inhibits inflammation. This application of herbal composite inclusion in dentistry and its applications has a greater potential to improve the success rate of dental implants and allows the implications of biotechnology in implant dentistry.

Periodontal disease leads to inflammation and consequently destruction of periodontium. The main aim of periodontal therapy is to minimize the inflammation by regeneration of defects. Over the past several decades, various materials as well as clinical techniques have been studied for repair and regeneration of periodontal defects. The tissue regeneration should permit proliferation of different cells in separate compartments, as four types of tissues constitute periodontium. Guided tissue regeneration (GTR) was introduced to restrict the growth of epithelium in alveolar bone space. Several barrier membranes were developed to aid in this technique which included both natural and synthetic materials. To achieve essential function of space maintenance, non-resorbable membranes were used previously with bone graft materials. Although these membranes were widely used, however they had many disadvantages which led to development of second generation (resorbable) and third generation (functional) membranes. This chapter focuses on advanced developments of biodegradable polymers for use in GTR treatment. Moreover, non-resorbable and resorbable polymeric membranes, classifications, advanced experimental research, clinical applications, and their challenges are also discussed. The composite periodontal membranes are also under research. Despite the biocompatibility and biodegradability of unreinforced barrier membranes, these are deficient in anti-bacterial properties. Therefore, barrier membranes blended with functional materials have been fabricated which exhibited more benefits. The comparison of past and recent trends of barrier membranes can guide correctly for periodontal regeneration therapy.

This paper aims to develop detection techniques and associated devices on irregular osseointegration during and after dental implant operations. More specifically, the study relates to the quantitative evaluation of an osseointegration between a dental implant and an alveolar bone through examining differences of dynamic characteristics of the dental implant and irregular bone defects. Developed techniques are able to inspect quantity, orientation and depth of bone defect. The associated device to this purpose is designed based upon the application of acoustic induced excitation and vibration response.