Depth distortion and angular deviation of a fully guided tooth-supported static surgical guide in a partially edentulous patient: A systematic review and meta-analysis.

PURPOSE: This systematic review and meta-analysis aimed to evaluate the depth distortion and angular deviation of fully-guided tooth-supported static surgical guides (FTSG) in partially edentulous arches compared to partially guided surgical guides or freehand. MATERIAL AND METHODS: This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in the Open Science Framework (OSF). The formulated population, intervention, comparison, and outcome (PICO) question was: "In partially edentulous arches, what are the depth distortion and angular deviation of FTSG compared to partially guided surgical guides or freehand?" The search strategy involved four main electronic databases, and an additional manual search was completed in November 2023 by following an established search strategy. Initial inclusion was based on titles and abstracts, followed by a detailed review of selected studies, and clinical studies that evaluated the angular deviations or depth distortion in FTSG in partial arches, compared to partially guided surgical guides or freehand, were included. In FTSG, two surgical approaches were compared: open flap and flapless techniques, and two digital methods were assessed for surgical guide design with fiducial markers or dental surfaces. A qualitative analysis for clinical studies was used to assess the risk of bias. The certainty of the evidence was assessed according to the grading of recommendations, assessment, development, and evaluations (GRADE) system. In addition, a single-arm meta-analysis of proportion was performed to evaluate the angular deviation of freehand and FTSG. RESULTS: Ten studies, published between 2018 and 2023, met the eligibility criteria. Among them, 10 studies reported angular deviations ranging from -0.32° to 4.96° for FTSG. Regarding FTSG surgical approaches, seven studies examined the open flap technique for FTSG, reporting mean angular deviations ranging from 2.03° to 4.23°, and four studies evaluated flapless FTSG, reporting angular deviations ranging from -0.32° to 3.38°. Six studies assessed the freehand surgical approach, reporting angular deviations ranging from 1.40° to 7.36°. The mean depth distortion ranged between 0.19 mm to 2.05 mm for open flap FTSG, and between 0.15 mm to 0.45 mm for flapless FTSG. For partially guided surgical guides, two studies reported angular deviations ranging from 0.59° to 3.44°. Seven studies were eligible for meta-analysis, focusing on the FTSG in open flap technique, with high heterogeneity (I2 (95%CI) = 92.3% (88.7%-96.4%)). In contrast, heterogeneity was low in studies comparing freehand versus FTSG in open flap techniques (I2 (95%CI) = 21.3% (0.0%-67.8%)), favoring the FTSG surgical approach. CONCLUSION: In partially edentulous arches, FTSG systems exhibited less angular deviation than freehand and partially guided surgical guides. Flapless surgical approaches were associated with reduced angular deviation and depth distortion, suggesting a potential preference for the FTSG method in these procedures.

Preloading peri-implant crestal bone loss: A retrospective study of incidence and related factors.

BACKGROUND: The aim of this study was to evaluate the incidence of preloading crestal bone loss (PLCBL) and to identify the patient-related and implant-related factors associated with PLCBL. METHODS: This retrospective cohort examined the dental records of patients who received at least one dental implant. PLCBL was defined as a reduction ⩾0.5 mm and severe PLCBL (primary variable) as a reduction ⩾1.5 mm in mesial and/or distal bone level, measured from the day of implant placement to uncovering or abutment installation/crown delivery. The incidence of PLCBL and patient and implant variables were recorded. Bivariate analysis and binary logistic regression identified factors associated with PLCBL ⩾0.5 mm and ⩾1.5 mm. RESULTS: A total of 746 dental implants placed in 361 patients from January 2011 to July 2021 was included in the analyses. Of the implants assessed, 24.4% (n = 182) exhibited PLCBL ⩾ 0.5 mm and 10.5% (n = 78) presented severe PLCBL (i.e., ⩾1.5 mm). Males (odds ratio [OR] = 1.85, 95% confidence interval [CI] = 1.11-3.07), patients with diabetes (OR = 3.33, 95% CI = 1.73-6.42), and those allergic to penicillin (OR = 3.13, 95% CI = 1.57-6.22) were more likely to experience severe PLCBL (p < 0.05). Implants placed in the anterior area (OR = 2.08, 95% CI = 1.16-3.73), with bone-level platform-abutment connection (OR = 4.73, 95% CI = 1.94-11.49) and inserted supracrestally (OR = 3.77, 95% CI = 1.84-7.72), presented a greater risk of developing severe PLCBL (p < 0.05). Implants placed in a previously grafted area presented a lower likelihood of developing severe PLCBL (OR = 0.489, 95% CI = 0.28-0.84). CONCLUSION: The incidence of PLCBL ⩾ 0.5 mm and ⩾1.5 mm was 24.4% and 10.5%, respectively. Male sex, diabetes, allergy to penicillin, anterior location, bone-level platform-abutment connection, and supracrestal implant placement are potential risk factors for severe PLCBL. A previously grafted area is a potential protective factor.

Linear Accuracy of Intraoral Scanners for Full-Arch Impressions of Implant-Supported Prostheses: A Systematic Review and Meta-Analysis.

This article compares the accuracy of intraoral scanners (IOSs) used in the digital impression of full arches to fabricate implant-supported complete prostheses. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered in the Open Science Framework (DOI 10.17605/OSF.IO/CPM9K). Six electronic databases, gray literature databases, and a manual search were performed in April 2022. Studies that evaluated the accuracy of intraoral scan impressions compared with conventional impressions in full-arch impressions were included for complete implant-supported prostheses. In addition, an adapted checklist for reporting in vitro studies was used to assess the risk of bias. Meta-analysis was conducted using a random-effects Hunter- Schmidt model. Nine studies were included in the analysis. IOS impressions present higher accuracy (137.86 µm) than conventional impressions (182.51 µm) (p<0.001). The heterogeneity of the study's methodology was I2»18.34. However, impression accuracy varies significantly with scan body type, IOS type, scanning strategy, and modification technique. For most IOS systems, the acceptable clinical threshold of linear accuracy of 200 µm can be achieved, except for the True Definition Scanner in one of the studies. Based on the results of the included studies, digital impressions using IOS present similar or better linear accuracy than conventional impression techniques.

The beyond the gap filling approach: Modeling facial and interproximal tissues and improving esthetics for anterior flapless immediate implant placement.

OBJECTIVE: Maintenance of adequate interproximal tissue height between an implant and a natural tooth or between adjacent implants represents an esthetic challenge in implant dentistry. The aim of this case report is to describe a modified technique referred to as the beyond the gap filling (BGF) approach designed to improve the horizontal and vertical components of the facial aspect and particularly the height of interproximal bone peaks around immediately placed implants into fresh extraction sockets. CLINICAL CONSIDERATIONS: Four patients (five teeth) requiring anterior tooth extraction were treated with the BGF approach that included: (a) minimally traumatic tooth extraction; (b) immediate implant placement without flap elevation; (c) installation of a narrow profile healing abutment to protect the implant during grafting; (d) grafting with a construct with 90% bovine bone granules and 10% porcine collagen packed coronally to the facial and interproximal bone walls above the level of the bone crest; and (e) delivery of an immediate restoration. CONCLUSIONS: The current report suggests that the level/height of the interproximal bone crests between an implant and a natural tooth or between two adjacent implants can be improved by the BGF approach and, consequently, papilla height can be maintained in cases with a high risk of papilla height collapse and, consequently, esthetic outcomes can be maximized. CLINICAL SIGNIFICANCE: The BGF is a simple technique to be used by clinicians to prevent significant papilla collapse in anterior immediate implants and consequently achieve maximum esthetic outcomes in implant dentistry.

Local effect of simvastatin combined with different osteoconductive biomaterials and collagen sponge on new bone formation in critical defects in rat calvaria.

PURPOSE: To evaluate the local effect of simvastatin (SVT) combined with deproteinized bovine bone (DBB) with hydroxyapatite/ß-tricalcium phosphate biphasic ceramics (HA/TCP) and with collagen sponge (CS) on bone repair in critical size defects (CSDs) in rat calvaria. METHODS: Forty-two 5-mm diameter CSDs were made bilaterally in the calvaria of 18 rats. The animals were allocated according to the type of biomaterial and associations used to fill the CSD. After 8 weeks, the animals were euthanized, and their calvaria were evaluated for repaired tissue composition using histologic and histometric analyses. RESULTS: In the histometric analysis, the use of SVT showed to increase bone formation in the CSDs when combined with all the bone substitutes tested in this study (p<0.05). Greater bone formation was observed in the groups with SVT compared to the groups without SVT. CONCLUSIONS: The use of SVT without the need for a vehicle and combined with a commercially available biomaterial may be a cheaper way to potentiate the formation of bone tissue without the need to produce new biomaterials. Therefore, SVT combined with DBB induced significantly greater new bone formation than did the other treatments.

Local effect of simvastatin combined with different osteoconductive biomaterials and collagen sponge on new bone formation in critical defects in rat calvaria

Abstract Purpose To evaluate the local effect of simvastatin (SVT) combined with deproteinized bovine bone (DBB) with hydroxyapatite/β-tricalcium phosphate biphasic ceramics (HA/TCP) and with collagen sponge (CS) on bone repair in critical size defects (CSDs) in rat calvaria. Methods Forty-two 5-mm diameter CSDs were made bilaterally in the calvaria of 18 rats. The animals were allocated according to the type of biomaterial and associations used to fill the CSD. After 8 weeks, the animals were euthanized, and their calvaria were evaluated for repaired tissue composition using histologic and histometric analyses. Results In the histometric analysis, the use of SVT showed to increase bone formation in the CSDs when combined with all the bone substitutes tested in this study (p<0.05). Greater bone formation was observed in the groups with SVT compared to the groups without SVT. Conclusions The use of SVT without the need for a vehicle and combined with a commercially available biomaterial may be a cheaper way to potentiate the formation of bone tissue without the need to produce new biomaterials. Therefore, SVT combined with DBB induced significantly greater new bone formation than did the other treatments.

Soft tissue cone beam computed tomography (ST-CBCT) for the planning of esthetic crown lengthening procedures.

OBJECTIVE: The aim of this study was to measure the clinical crown, anatomical crown, and amount of gingiva covering the enamel of anterior maxillary teeth with soft tissue cone beam computed tomography (ST-CBCT) and thus propose a protocol for the application of this noninvasive method for the planning of esthetic crown lengthening procedures to prevent undesired root exposure. MATERIALS AND METHODS: Ten young patients (mean age 22.8 years) requiring esthetic crown lengthening surgeries but not restorative procedures were included in this study. The ST-CBCT images were analyzed with an image editor and analysis software (Pixelmator 3.2), and the clinical crown, anatomical crown, and amount of gingiva covering the enamel were measured. RESULTS: The mean value of the length of the anatomical crowns of the central incisors, lateral incisors, and canines were 11.06 mm, 9.55 mm, and 9.77 mm, respectively. Thus, the canines were approximately 1.3 mm shorter than the central incisors. CONCLUSION: It was shown that ST-CBCT is a useful tool to assess the actual length of the anatomical crown and the amount of gingival tissue that needs to be surgically removed in an esthetic crown lengthening procedure to prevent undesired root exposure. Thus, ST-CBCT is a helpful noninvasive procedure for the planning of esthetic crown lengthening surgeries, making it possible to better predict their final outcome.

Simvastatin and biphasic calcium phosphate affects bone formation in critical-sized rat calvarial defects.

PURPOSE: To investigate the effects of locally applied simvastatin plus biphasic calcium phosphate (BoneCeramic(r)) or collagen sponge on bone formation in critical-sized bone defects. METHODS: Thirty defects of 5mm in diameter were created bilaterally with a trephine bur in the calvariae of fifteen Wistar rats. The defects were divided into five groups: group 1 - control, no treatment; group 2 (BoneCeramic(r)); group 3 (BoneCeramic(r) + 0.1mg simvastatin); group 4 (collagen sponge); and group 5 (collagen sponge + 0.1mg simvastatin). After eight weeks the animals were euthanized and their calvariae were histologically processed. Hematoxylin and eosin-stained sections were subjected to histological and histomorphometrical analyses. The area of newly formed bone was calculated and compared between groups. RESULTS: The greater amount of a bone-like tissue was formed around the carrier in group 3 (BoneCeramic(r) + 0.1mg simvastatin) followed by group 2 (BoneCeramic(r)), and almost no bone was formed in the other groups. Group 3 was significantly different compared to group 2, and both groups were significantly different compared to the other groups. CONCLUSION: Simvastatin combined with BoneCeramic(r) induced significantly greater amounts of newly formed bone and has great potential for the healing of bone defects.

Abfraction lesions: etiology, diagnosis, and treatment options.

Abfraction is a type of noncarious cervical lesion (NCCL) characterized by loss of tooth tissues with different clinical appearances. Evidence supports that abfraction lesions, as any NCCLs, have a multifactorial etiology. Particularly, the cervical wear of abfraction can occur as a result of normal and abnormal tooth function and may also be accompanied by pathological wear, such as abrasion and erosion. The interaction between chemical, biological, and behavioral factors is critical and helps to explain why some individuals exhibit more than one type of cervical wear mechanism than others. In an era of personalized dentistry, patient risk factors for NCCLs must be identified and addressed before any treatment is performed. Marked variations exist in dental practice concerning the diagnosis and management of these lesions. The lack of understanding about the prognosis of these lesions with or without intervention may be a major contributor to variations in dentists' management decisions. This review focuses on the current knowledge and available treatment strategies for abfraction lesions. By recognizing that progressive changes in the cervical area of the tooth are part of a physiologically dynamic process that occurs with aging, premature and unnecessary intervention can be avoided. In cases of asymptomatic teeth, where tooth vitality and function are not compromised, abfraction lesions should be monitored for at least 6 months before any invasive procedure is planned. In cases of abfraction associated with gingival recession, a combined restorative-surgical approach may be performed. Restorative intervention and occlusal adjustment are not indicated as treatment options to prevent further tooth loss or progression of abfraction. The clinical decision to restore abfraction lesions may be based on the need to replace form and function or to relieve hypersensitivity of severely compromised teeth or for esthetic reasons.

Simvastatin and biphasic calcium phosphate affects bone formation in critical-sized rat calvarial defects

ABSTRACT PURPOSE: To investigate the effects of locally applied simvastatin plus biphasic calcium phosphate (BoneCeramic(r)) or collagen sponge on bone formation in critical-sized bone defects. METHODS: Thirty defects of 5mm in diameter were created bilaterally with a trephine bur in the calvariae of fifteen Wistar rats. The defects were divided into five groups: group 1 - control, no treatment; group 2 (BoneCeramic(r)); group 3 (BoneCeramic(r) + 0.1mg simvastatin); group 4 (collagen sponge); and group 5 (collagen sponge + 0.1mg simvastatin). After eight weeks the animals were euthanized and their calvariae were histologically processed. Hematoxylin and eosin-stained sections were subjected to histological and histomorphometrical analyses. The area of newly formed bone was calculated and compared between groups. RESULTS: The greater amount of a bone-like tissue was formed around the carrier in group 3 (BoneCeramic(r) + 0.1mg simvastatin) followed by group 2 (BoneCeramic(r)), and almost no bone was formed in the other groups. Group 3 was significantly different compared to group 2, and both groups were significantly different compared to the other groups. CONCLUSION: Simvastatin combined with BoneCeramic(r) induced significantly greater amounts of newly formed bone and has great potential for the healing of bone defects.

Entrevista com David L Cochran / An interview with David L. Cochran

Dr. David L. Cochran é graduado pela University of Virginia e recebeu os títulos de DDS, MS e PhD em Bioquímica pela Medical College of Virginia. Especializou-se em Periodontia pela Harvard School of Dental Medicine, onde também recebeu um segundo título de mestre. Recentemente, o Dr. Cochran recebeu o título de Doctor HonorisCausa pela University of Bern, na Suíça. Atualmente, é professor e chefe do Departamento de Periodontia na Faculdade de Odontologia da University of Texas Health Science Center, na cidade de San Antonio, nos Estados Unidos. Antes de assumir o cargo em San Antonio, era diretor do programa de pós-graduação em Periodontia naMedical College of Virginia. Dr. Cochran é membro de muitas organizações profissionais de Odontologia e diplomado pelo American Board of Periodontology. Além disso, é membro do American College of Dentistry e do International College of Dentistry.Dr. Cochran publicou inúmeros artigos científicos e resumos sobre vários tópicos relacionados à Periodontia, Bioquímica e Implantodontia. Recebeu prêmios nacionais e internacionais por suas pesquisas, e é um pesquisador clínico e científico ativo financiado tanto pela NIH-NIDCR (National Institutes of Health / National Institute of Dental and Craniofacial Research) quanto pela indústria privada...

Dr. David L. Cochran is a graduate of the University of Virginia and received hisDDS., MS. and PhD degrees in Biochemistry from the Medical College of Virginia (MCV). He was trained in Periodontology at the Harvard School of Dental Medicine where he also obtained a second Masters degree. He recently received an Honorary Doctorate from the University of Bern in Switzerland. Dr. Cochran is currently Professor and Chairman of the Department of Periodontics at The University of Texas Health Science Center at San Antonio, Dental School. Prior to his appointmentat San Antonio, Dr. Cochran was Director of Postgraduate Periodontics atMCV. Dr. Cochran is a member of many professional dental organizations and isa Diplomate of the American Board of Periodontology. He is a fellow of the American College of Dentistry and the International College of Dentistry. Dr. Cochran has published numerous scientific articles and abstracts on various periodontal, biochemistry, and implant topics. He has received awards for his research work at both the national and international levels. Dr. Cochran is an active basic science and clinical researcher who has received funding from both the NIH-NIDCR andprivate industry...

Behavioural and cognitive effects of simvastatin dose used in stimulation of bone regeneration in rats.

PURPOSE: To analyze the effects of simvastatin (SVT) in the locomotion, anxiety and memory of rats, as a reflection of the administration of a minimum dose capable of stimulating bone regeneration in defects in the calvariae. METHODS: Surgical procedures were performed in 15 female Wistar rats, 2-month old, to insert the grafting material regenerator (Bone-ceramic®) and/or SVT, followed by behavioural and cognitive assessments in the 7th, 30th and 60th days post surgery. RESULTS: The SVT locally applied with the goal of bone regeneration in defects created in rat calvariae does not interfere with locomotion, anxiety levels and/or memories of rats, except for the first week following surgery, when an anxiolytic effect was observed, as a result of a possible central action. CONCLUSION: Failure to provoke any response within 30 and 60 days post surgical procedures suggests that SVT may constitute a good choice in stimulating bone regeneration without affecting the long term neural functions.

Behavioural and cognitive effects of simvastatin dose used in stimulation of bone regeneration in rats

To analyze the effects of simvastatin (SVT) in the locomotion, anxiety and memory of rats, as a reflection of the administration of a minimum dose capable of stimulating bone regeneration in defects in the calvariae. METHODS: Surgical procedures were performed in 15 female Wistar rats, 2-month old, to insert the grafting material regenerator (Bone-ceramic(r)) and/or SVT, followed by behavioural and cognitive assessments in the 7th, 30th and 60th days post surgery. RESULTS: The SVT locally applied with the goal of bone regeneration in defects created in rat calvariae does not interfere with locomotion, anxiety levels and/or memories of rats, except for the first week following surgery, when an anxiolytic effect was observed, as a result of a possible central action. CONCLUSION: Failure to provoke any response within 30 and 60 days post surgical procedures suggests that SVT may constitute a good choice in stimulating bone regeneration without affecting the long term neural functions.

Dimension of the facial bone wall in the anterior maxilla: a cone-beam computed tomography study.

OBJECTIVE: To determine the thickness of the facial bone wall in the anterior dentition of the maxilla and at different locations apical to the cemento-enamel junction (CEJ). MATERIAL AND METHODS: Two-hundred and fifty subjects, aged between 17 and 66 years, with all maxillary front teeth present were included. Written informed consents were obtained. Cone-beam computed tomography scans were performed with the iCAT unit. This examination included all tooth and edentulous sites in the dentition. The images were acquired by means of the iCAT software and processed by a computer. Measurements of the (i) distance between the CEJ and the facial bone crest and (ii) the thickness of the facial bone wall were performed. The bone wall dimensions were assessed at three different positions in relation to the facial bone crest, i.e., at distances of 1, 3, and 5 mm apical to the crest. RESULTS: The measurements demonstrated that (i) the distance between the CEJ and the facial bone crest varied between 1.6 and 3 mm and (ii) the facial bone wall in most locations in all tooth sites examined was ≤1 mm thick and that close to 50% of sites had a bone wall thickness that was ≤0.5 mm. CONCLUSION: Most tooth sites in the anterior maxilla have a thin facial bone wall. Such a thin bone wall may undergo marked dimensional diminution following tooth extraction. This fact must be considered before tooth removal and the planning of rehabilitation in the anterior segment of the dentition in the maxilla.

Efeito de superfícies de implantes nano-estruturadas na expressão de genes de osteoblastos e no contato osso-implante in vivo / Effect of nanostructured implant surfaces on osteoblast related gene expression and bone-implant contact in vivo

As tendências atuais na terapia com implantes odontológicostêm incluído o uso de implantes com superfícies modificadasutilizando nanotecnologia. Ciência que permite a construçãode novos materiais e dispositivos pela manipulação de átomosindividuais e moléculas (escala menor do que 100nm). O objetivodeste trabalho foi avaliar o papel das modificações em escalananométrica de superfícies de implantes osseointegradospara melhorar o processo de osseointegração. Nanotecnologiaoferece a engenheiros e profissionais da área de biologia e saúdenovos meios para entender e otimizar funções e respostasespecíficas de células. As várias técnicas utilizadas para adicionarcaracterísticas nanométricas às superfícies de implantesosseointegrados são descritas neste trabalho. Vários trabalhostem apresentado os efeitos da nanotecnologia na modulaçãode etapas fundamentais do processo de osseointegração. Asvantagens e desvantagens da utilização da nanotecnologia nasuperfície de implantes também são discutidas nesse trabalho.Posteriormente, em uma série de experimentos in vitro e in vivo,foi possível avaliar o efeito específico destas modificações emdois diferentes modelos. Como efeitos observados da aplicaçãode nanoestruturas à superfície dos implantes osseointegradosfoi possível verificar-se uma melhor e mais rápida resposta deosseointegração destes materiais, atuando efetivamente na cascatade diferenciação de osteoblastos.

Current trends in clinical dental implant therapy include useof endosseous dental implant surfaces embellished with nanoscaletopographies. Nanotechnology deals with materials withat least one significant dimension less than 100nm. The goal ofthis study was to consider the role of nanoscale topographic modificationof titanium substrates for the purpose of improvingosseointegration. Nanotechnology offers engineers and biologistsnew ways of interacting with relevant biological processes.Moreover, nanotechnology has provided means of understandingand achieving cell specific functions. The various techniquesthat can impart nanoscale topographic features to titaniumendosseous implants are described. Existing data supportingthe role of nanotopography suggests that critical steps in osseointegrationcan be modulated by nanoscale modification ofthe implant surface. Important distinctions between nanoscaleand micron-scale modification of the implant surface are presentlyconsidered. The advantages and disadvantages of nanoscalemodification of the dental implant surface are discussed.Finally, available data concerning the current dental implantsurfaces that utilize nanotopography in clinical dentistry aredescribed. Nanoscale modification of titanium endosseous implantsurfaces can alter cellular and tissue responses that maybenefit osseointegration and dental implant therapy. In a seriesof in vitro and in vivo experiments it was possible to evaluatethe effect of this modifications in different study designs. Theadvantages of the use of nanocues added to the surface of theosseointegrated dental implants allowed to a better and fasterosseointegration response of these materials, by acting on thedifferentiation of the osteoblasts.

Nanostructured alumina-coated implant surface: effect on osteoblast-related gene expression and bone-to-implant contact in vivo.

PURPOSE: The use of nanotechnology to enhance endosseous implant surfaces may improve the clinical control of interfacial osteoblast biology. This study investigated the influence of a nanostructure-coated implant surface on osteoblast differentiation and its effects on bone-to-implant contact (BIC) and removal torque values. MATERIALS AND METHODS: Titanium disks were machined (M) or machined and subsequently treated by acid etching (Ac) or by dipping in an aluminum oxide solution (Al2O3). Surfaces were characterized by scanning electron microscopy, atomic force microscopy, and x-ray microanalysis. For the in vitro experiment, rat mesenchymal stem cells (rMSCs) were grown in osteogenic supplements on the disk surfaces for 3 days. Real-time polymerase chain reaction (PCR) was used to measure mRNA levels of several gene products (bone sialoprotein, osteocalcin, osteopontin, and RUNX-2). For the in vivo experiment, titanium implants were placed in rat tibiae and harvested after 3 to 21 days for measurement of bone-specific mRNA levels by real-time PCR. Removal torque and BIC were measured 3 to 56 days after placement. RESULTS: Average height deviation (Sa, in nm) values for M, Ac, and Al2O3 implants were 86.5, 388.4, and 61.2, respectively. Nanostructured Al2O3 topographic features applied to machined implants promoted MSC commitment to the osteoblast phenotype. Greater bone-specific gene expression was observed in tissues adjacent to Al2O3 implants, and associated increases in BIC and torque removal were noted. CONCLUSION: Nanostructured alumina may directly influence cell behavior to enhance osseointegration.

A new method to assess and measure palatal masticatory mucosa by cone-beam computerized tomography.

AIM: The aim of this study was to apply a novel method to obtain high-quality images by cone-beam computerized tomography (CBCT) that consistently allowed the determination of the dimensions of the palatal mucosa. MATERIALS AND METHODS: Thirty-one patients participated in this study. At the time of the CBCT scanning, the patients wore a plastic lip retractor and wooden spatulas to retract soft tissues away from the teeth and gingiva. The thickness of the palatal mucosa was obtained at forty different locations on each patient. RESULTS: Retraction of the lips and cheek allowed a clear observation and measurements of the thickness of the palatal masticatory mucosa. The average thickness of the palatal mucosa was 2.92 mm in the canine area, 3.11 mm at the first pre-molar, 3.28 mm at the second pre-molar, 2.89 mm at the first molar and 3.15 mm at the second molar. Statistical differences were observed at different ages and heights of measurements. CONCLUSIONS: A new non-invasive method to consistently obtain high-quality images of the palatal masticatory mucosa is described. Measurements of this mucosa could be obtained at different locations on the palate.

The effects of implant surface nanoscale features on osteoblast-specific gene expression.

This study investigated the influence of nanoscale implant surface features on osteoblast differentiation. Titanium disks (20.0 x 1.0 mm) with different nanoscale materials were prepared using sol-gel-derived coatings and characterized by scanning electron microscopy, atomic force microscopy and analyzed by X-ray Photoelectron Spectrometer. Human Mesenchymal Stem Cells (hMSCs) were cultured on the disks for 3-28 days. The levels of ALP, BSP, Runx2, OCN, OPG, and OSX mRNA and a panel of 76 genes related to osteogenesis were evaluated. Topographical and chemical evaluation confirmed nanoscale features present on the coated surfaces only. Bone-specific mRNAs were increased on surfaces with superimposed nanoscale features compared to Machined (M) and Acid etched (Ac). At day 14, OSX mRNA levels were increased by 2-, 3.5-, 4- and 3-fold for Anatase (An), Rutile (Ru), Alumina (Al), and Zirconia (Zr), respectively. OSX expression levels for M and Ac approximated baseline levels. At days 14 and 28 the BSP relative mRNA expression was significantly up-regulated for all surfaces with nanoscale coated features (up to 45-fold increase for Al). The PCR array showed an up-regulation on Al coated implants when compared to M. An improved response of cells adhered to nanostructured-coated implant surfaces was represented by increased OSX and BSP expressions. Furthermore, nanostructured surfaces produced using aluminum oxide significantly enhanced the hMSC gene expression representative of osteoblast differentiation. Nanoscale features on Ti implant substrates may improve the osseointegration response by altering adherent cell response.

Avaliação do comportamento de células mesenquimais humanas sobre superfícies de implantes dentários / Evaluation of differentiation and mineralization of human mesenchymal cells plated on dental implant surfaces

O objetivo deste estudo foi avaliar uma superfície de implante dentário compatível biologicamente e que aumente a resposta celular de osteoblastos de maneira a estimular o processo de diferenciação do tecido ósseo. Neste estudo foram utilizados discos de titânio comercialmente puro (cpTi) grau IV (6,0 mm x 1,0 mm) divididos em três grupos. Estes discos foram somente usinados (grupo U) ou usinados e subsequentemente tratados com ataque ácido (grupo Ac) ou usinado, jateamento e ataque ácido (grupo J/Ac). Células mesenquimais humanas indiferenciadas foram cultivadas sobre os discos e diferenciadas em osteoblastos. Os níveis de expressão de genes relacionados à diferenciação do tecido ósseo (Fostatase Alcalina-ALP; Sialoproteína Óssea-BSP; e Runx2) foram avaliados após sete e 21 dias através de PCR-tempo real (o gene GAPDH foi utilizado como controle endógeno). Após 35 dias avaliou-se a formação de nódulos de mineralização corados com Alizarin Red S. Observou-se um aumento relativo nos níveis de expressão dos genes ALP, BSP e Runx2 para a superfície com J/Ac quando comparada com as superfícies U e Ac. Após 21 dias a expressão de ALP estava 80 vezes maior na superfície J/Ac e o aumento no nível de BSP foi de 25 vezes. Após 35 dias a área mineralizada foi de 18%, 71% e 80%, para as superfícies U, Ac e J/Ac, respectivamente. Estes resultados sugerem que o jateamento da superfície previamente ao ataque ácido permitiu um maior nível de expressão de genes relacionados à cascata de diferenciação do tecido ósseo e formação de nódulos de mineralização in vitro, podendo levar a uma maior e melhor resposta de osseointegração destas superfícies.

Novel implant surfaces have been developed to improve/accelerate the osseointegration process. The mechanism by which implant surface improves osteoblast response at endosseous titanium implants is not fully understood. One of the mechanisms is related to induction of expression of bone-tissue specific genes inducing cells to differentiate into osteoblasts. The aim of this study was to evaluate a biologically compatible implant surface that can improve osteoblast responses and leads to a faster osseointegration. Commercially pure grade IV titanium disks (6.0x1.0mm) were machined (U) or machined acid etching (Ac) or sandblasted/acid etching (J/Ac), and divided into three groups. Human Mesenchymal Stem Cells were plated onto the disks and differentiated into osteoblasts. The expression levels of osteoblast-specific genes were evaluated by Real Time PCR to measure the mRNA levels of alkaline phosphatase (ALP), bone sialoprotein (BSP), and Runx2 after 7 and 21 days. The housekeeping gene GAPDH was used as a control. At 35 days, mineralization nodules were evaluated by Alizarin Red S staining. After 21 days, the expression levels of ALP for J/Ac and BSP were upregulated 80-fold and 25-fold, respectively. After 35 days, the mineralized area U, Ac and J/Ac was 18%, 71%, and 80%, for, respectively. The results demonstrated that a sandblasted/acid etched surface can affect adherent cell-bone specific gene expression, leading to a higher expression of osteoblast-specific genes and an increased in vitro mineralization response.

Effect of resin adhesive systems on root caries formation in vitro.

OBJECTIVE: To evaluate the capability of different adhesive systems to inhibit in vitro caries formation. METHOD AND MATERIALS: Four materials were tested: Gluma Comfort Bond (GL; Heraeus Kulzer), Gluma Comfort Bond + Desensitizer (GL+; Heraeus Kulzer), iBond (iB; Heraeus Kulzer), and One-up Bond F (OUB; Tokuyama). Bovine roots were ground to obtain flat mesial and distal dentin surfaces. Nail varnish was applied to the entire root surface except for two 10 mm X 2 mm windows on the flattened surfaces. The adhesives were applied to the exposed areas according to the manufacturers' instructions. The roots were incubated at 37 degrees C for 1 week in a suspension of StreptococcuS mutans and Lactobacillus acidophilus. Control groups either received no root surface treatment or were etched with 37% phosphoric acid (without immersion in the bacterial suspension). Specimens were sectioned perpendicular to the long axis of the roots, stained for 24 hours with Rhodamine B, and analyzed with confocal laser microscopy. The data were analyzed by 1-way ANOVA and Fisher's PLSD test at 95% confidence level. RESULTS: Lesions in the OUB, iB, and GL+ groups were significantly shallower than those in the no-treatment group. Acid etching did not produce any measurable lesions. Mean lesion depth in the GL group was similar to that in the no-treatment group. There was no significant difference between mean lesion depths in the GL+, GL, and iB groups. CONCLUSION: Fluoride- and glutaraldehyde-containing adhesive systems might be an aid in root caries prevention.