Search

Introduction Structural defects created by endodontic treatment are the most common cause of major dental failures. This study analyzed levels of stress produced by endodontic instruments during the root canal treatment by Photoelastic Analysis of Stress. Methods Twenty-four human premolars were randomly divided into four groups (n=6) according to instrumentation protocol: ProTaper Next (GPT), One Shape (GOS), Wave One Gold (GWO), and TF Adaptive (GTF). The evaluation of the photoelastic model was performed at four- dental zones: dental-crown region, cervical third of root, middle third of root and apical third of root). Silicone molds were prepared (2mmx15mm) and pinjets were used inside the root canals to fixate teeth. Photoelastic resin (2:1ratio) was poured into the silicone molds to form photoelastic models. A transmission polariscope was used to analyze the positions of interest and recorded with a digital camera. Tardy's method was used to quantify the fringe order(n) and calculate the maximum stress value(τ) at each selected point. Data were analyzed with a two-way ANOVA, Tukey's test(p Results All groups showed a significant increase in the level of stress created during biomechanical preparation of the root canals. In the quantitative analysis, there was no statistically significant difference among the groups(p> 0.05). In the qualitative analysis, GPT and GTF instruments achieved greater levels of stresses compared to GWO and GOS instruments. At the beginning of instrumentation, stresses were concentrated at the coronary level, and the end of instrumentation at the middle and apical root level. Conclusions All endodontic systems resulted in accumulation of stress along the dental structure. Stress was found in different concentrations along the tooth and at different levels.

BACKGROUND Endodontically treated teeth usually can reveal an extensive loss of dental structure and require the use of intraradicular posts to provide adequate support and retention. Retention of the post depends on the surface treatment of the endodontic post itself and on the root canal dentin as well as on the type of resin-matrix cement. PURPOSE The main aim of this study was to conduct an integrative review on the influence of different surface treatment methods of glass fiber-reinfored resin composite (GFRC) posts on their push-out bond strength to resin-matrix cements in endodontically treated teeth rehabiliation. METHOD A literature search was performed on PubMed (via National Library of Medicine) regarding articles published within the last 10 years, using the following combination of search terms: "intracanal post" OR "endodontic post" OR "root canal post" OR "intraradicular post" OR "glass fiber" AND "resin cement" AND "adhesion" OR "bond strength" OR "shear bond strength" OR "push out". RESULTS Results from the selected studies recorded the highest push-out bond strength around 22.5 MPa) on GFRC posts to resin-matrix cements when the surfaces were pre-treated by grit-blasting with silicate followed by silane conditioning. However, high values of push-out bond strength (21.5 MPa) were also noticed for GFRC posts after etching with hydrogen peroxide followed by silance conditioning. Thus, the highest values of bond strength of endodontic posts to the resin-matrix cements were recorded when a combined physico-chemical approach was assessed. Non-treated surfaces showed the lowest bond strength values between 5 to and 9 MPa. Surface analyses of GFRC posts showed an increased roughness after grit-blasting or etching that promoted a mechanical interlocking of the adhesive and resin-matrix cements. CONCLUSION The combined treatment of glass fiber-reinforced resin composite post surfaces by physical and chemical methods can promote the increase in roughness and chemical functionalization of the surfaces prior to cementation., That results in a high mechanical interlocking of the resin-matrix cements and a stable retention of the teeth root intracanal posts. CLINICAL RELEVANCE Combining chemical and physical modification methods of surfaces can provide the most promising adhesion-enhancing pathways of GFRC posts to resin-matrix cements, that can decrease the risk of clinical failures by fracture and detachment of endodontic posts.

Root-filled teeth that receive ceramic veneers may experience subsequent coronal discolouration, which will likely negatively affect the quality of life of patients and their relationship with the clinician. This manuscript describes three cases of this undesirable aesthetic consequence in anterior teeth of young patients and the subsequent restorative reintervention, with satisfactory results. In all three reports, the root canal filling was performed using cements containing bismuth oxide that likely disassociated into reduced metallic crystals when in contact with LED light. The discolouration observed after veneer cementation was most likely caused by the accumulation of these bismuth metallic crystals. These cases highlight the importance of preventing this undesirable complication, which may also result in the potential subsequent further sacrifice of sound coronal dental structure, and the role of recall in aesthetically demanding clinical cases.

Aim: The patient was followed up in consultation with the orthodontist, and after a long-term follow-up, it was found that the dental germ developed, but the position of the tooth was horizontal. When the follow-ups were continued, it was observed that the position of the tooth also improved, and it progressed smoothly along the tooth eruption path. Methodology: In the panoramic radiography of an 8-year-old male patient who applied to the clinic complaining about the left upper first primary molar tooth, the right lower permanent second premolar tooth follicle developed, but there was no tooth development in the follicle. Results: When follicle formation is observed, only following the patients without directing them to orthodontic treatment, which is expensive and difficult, positively affects their dental structure. Following patients without affecting their lives can be significant. Conclusion: We emphasize the importance of long-term follow-up when follicle formation was observed. We predicted that this situation was caused by the disconnection in the interaction of transcription factors and signals in the tooth development stage. How to cite this article: Sukurica Y, Çakır A. Long-term follow-up in lower right second premolar tooth with a dental follicle but no tooth bud: A case report. Int Dent Res 2021;11(Suppl.1):312-5. https://doi.org/10.5577/10.5577/intdentres.2021.vol11.suppl1.47 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

This study investigated the impacts of geometry, thickness, and material on damage growth in a porcelain-metal restoration structure by utilizing a computational approach. Extended finite element method (XFEM) was used to find the critical loads causing the nucleation of radial cracks at the porcelain undersurface. Plastic deformation also was considered at the metal above the surface as another damage mechanism. The dental system consisted of a brittle outerlayer (porcelain)/metal (Pd/Co/Au alloys)-core/dentin-substrate trilayer system. A tungsten-carbide hemisphere as an indenter was used to apply a compressive loading on the structure. In addition, two different geometries were created to present the dental structure, cylinder, and tapered cylinder. The results showed that a harder and stiffer metal core can resist the initiation of radial cracks. It was also observed that the metal with thinner layers is more vulnerable to radial cracking. In all simulations, the tapered cylinder geometry showed to have higher critical loads in both damage modes. The optimum thickness for the porcelain layer was suggested to be 0.5 mm. The geometry of dental crown-like structures was found to be an important factor in damage initiation. The findings also proposed that the metal layer should not be designed very thin in order to prevent the formation of radial cracks. This numerical investigation also recommended that the stiffness of the metal layer is better to keep higher compared to other layers to hinder the initiation of radial cracks.

Vital pulp therapy (VPT) is deliberated as an ultraconservative/minimally invasive approach for the conservation of vital pulpal tissues, preservation of dental structure, and maintenance of tooth function in the oral cavity. In VPT, following the exposure of the dental pulp, the environment is prepared for the possible healing and probable refunctionalisation of pulpal connective tissue. However, to succeed in VPT, specific biomaterials are used to cover and/or dress the exposed pulp, lower the inflammation, heal the dental pulp, provoke the remaining odontoblastic cells, and induce the formation of a hard tissue, i.e., the dentinal bridge. It can be assumed that if the employed biomaterial is transferred to the target site using a specially designed micro-/nanosized local drug delivery system (LDDS), the biomaterial would be placed in closer proximity to the connective tissue, may be released in a controlled and sustained pattern, could properly conserve the remaining dental pulp and might appropriately enhance hard-tissue formation. Furthermore, the loaded LDDS could help VPT modalities to be more ultraconservative and may minimise the manipulation of the tooth structure as well as pulpal tissue, which could, in turn, result in better VPT outcomes.

Noncarious cervical lesions (LCNC) present as irreversible loss of dental structure in the cervical region without bacterial involvement, having a complex and multifactorial etiology. Associated with stress, the loss of dental tissue in this region has been understood by occlusal factors, associating the lesion with bruxism, tightening and premature contact, and is associated with dietary, parafunctional habits, time of the teeth in the mouth and greater attempt of hygiene. This study aimed to compare the stress levels in the patients attended at the Clinical School of Dentistry of the UFCG and who presented or not LCNC. The study adopted as strategy the data collection of the Lipp Stress Symptoms questionnaire (ISSL). In this questionnaire phase I corresponds to the experience of stress in the last 24 hours, phase II in the last week and phase III in the last month. The data were collected from March to May 2019 and the same was approved by the CEP. The sample consisted of 151 participants, 100 (66.2%) were women and 51 (33.8%) men, of whom, 26 (50.9%) were in the phase of exhaustion (Phase III), and of 100 women, 52 (52%) were also at that level. When asked about the stomatognathic system, dry mouth was the most reported among men (56.7%) and women (35.7%) without LCNC. Among the women with these lesions, muscle tension was the most marked (50%). Therefore, stress can lead to the appearance of disorders in the stomatognathic apparatus.

Introdução: As manchas dentárias, dentre elas a hipoplasia do esmalte corresponde a um dos motivos que fazem com que os pacientes busquem alterações no seu sorriso. O tratamento proposto deve ser sempre o mais conservador possível e buscar devolver a autoestima do paciente. Objetivo: Este trabalho objetivou apresentar um relato de caso clínico de paciente do sexo feminino, 26 anos, insatisfeita com a estética do seu sorriso por apresentar dentes escurecidos e hipoplasia de esmalte na face vestibular, em incisivo superior. Descrição do caso: Ao exame clínico foi observado escurecimento fisiológico e hipoplasia de esmalte no incisivo lateral superior esquerdo (22).O plano de tratamento proposto foi clareamento dental pela técnica associada (técnica de consultório + técnica caseira), remoção da mancha hipoplásica de forma minimamente invasiva e restauração em resina composta direta. Conclusões: Através de um correto diagnóstico, associado a uma técnica e seleção de material adequado, é possível conseguir excelência estética com preservação de estrutura dentária sadia.

Purpose To evaluate the clinical behavior and survival of full coverage monolithic zirconia crowns on posterior teeth over a 5-year follow-up. Methods Fifty patients were recruited and underwent restoration with a Lava Plus monolithic zirconia crown (Lava™ Frame Zirconia, 3M Espe, Germany) on premolars or molars. Patients were monitored over a 5-year follow-up (2014-19), recording any biological and/or mechanical complications; these data were used to estimate the crowns' success rate. Periodontal clinical parameters were recorded (pocket probing depth (PPD), plaque index (PLI), bleeding on probing (BOP), and gingival recession (GR)). Wear to the zirconia crowns and antagonist teeth were also evaluated with Geomagic software (3D Systems, U.S.A.). Patients' satisfaction with treatment was evaluated in a questionnaire. Results For the 50 monolithic zirconia crowns analyzed, the survival rate was 98% after 5 years. Only 6% of the crowns presented some type of complication (two debonding and one root fracture). No fracture or fissures were detected. GR and BOP were the only clinical parameters found to be significantly greater around teeth restored with crowns. The monolithic zirconia crowns suffered less wear than the enamel of antagonist teeth. Patient's general satisfaction with treatment was high. Conclusions Monolithic zirconia crowns on posterior teeth are a highly predictable treatment option, with a high survival rate. The single treatment failure was due to a biological complication arising from root fracture. This treatment may be recommended as a treatment that conserves dental structure, and requires minimal dental preparation.

Introduction. The purpose of this systematic review was to compare the accuracy of the three-dimensional images among different scanners, scanning techniques, and substrates. Materials and methods. Electronic databases (PubMed and Elsevier) were searched until March 2020. The systematic search was performed to identify the most precise method of obtaining a 3D image of the dentition. Results. Thirteen articles out of 221, considering the accuracy of 3D images, were selected. The main factors that are considered to have an influence on the precision are substrate type in the oral cavity, experience of the scanner’s operator, direct vs. indirect scanning, and the reproducibility of the procedure. Conclusion. Substrate type does have an impact on the overall accuracy of intraoral scans where dentin has the most and enamel the least accurately recorded dental structure. Experience of the operator has an influence on the accuracy, where more experienced operators and smaller scan sizes are made for more accurate scans. A conventional impression technique in a full-arch image provided the lowest deviation. The reproducibility of direct scanning was comparable to indirect scanning although a slight difference was noticeable (0.02 mm).

Background: The growing demands for esthetic restorations have stimulated intensive research in the field of adhesive dentistry. Dental adhesive systems are used to promote adhesion between composite resins and dental structure. In the fundamental principles of adhesion, the primary mechanism contributing to the formation of adhesion is micromechanical bonding between the restoration and the tooth. The bond strength of self-etching adhesives to dentin was found to be almost equal to that of total-etch adhesives. The aim of the present prospective, double-blind, randomized controlled clinical trial was to evaluate and compare the clinical performance of two self-etch adhesive systems with total-etch adhesive system in noncarious cervical lesions (NCCLs). Materials and Methods: In each patient, three teeth were randomly assigned according to the adhesive system used to Group A (total-etch adhesive system), Group B (two-bottle self-etch adhesive system), and Group C (one-bottle self-etch adhesive system). The clinical efficacy of these adhesive systems was determined by evaluating the retention rate, marginal integrity, and postoperative sensitivity at the following three levels: baseline, 6 months, and 18 months by following the Modified USPHS criteria introduced by Vanherle et al. Results: In the present study, the retention rate at 18 month in Group A, Group B, and Group C of 96%, 92%, and 92% was observed, respectively. A marginal integrity at 18 months was 88%, 80%, and 84% for Group A, Group B, and Group C, respectively. Postoperative sensitivity at 18 months was 16%, 12%, and 12% for Group A, Group B, and Group C, respectively. Conclusion: The clinical performance of total-etch and self-etch adhesive systems in NCCLs did not differ significantly with regard to the evaluated parameters – retention, marginal integrity, and postoperative sensitivity.

Objective: The present study aims to describe a literature review on post and core restorations from a new clinical perspective in dentistry. Also, to define the best choice regarding the intraradicular retainer, material used, confection techniques and their possible failures, explaining the myths and the truths about them. Methodology: This literature review was conducted by leading health databases: Pubmed (https://www.ncbi.nlm.nih.gov/pubmed), SCIELO (www.scielo.org) e Google Scholar (https://scholar.google.com.br). The keywords for the textual search were: Denture, Partial, Fixed; Post and Core Technique; Dental Research; Dentistry. Inclusion criteria were: literature on the subject under study, literature of recent years, english and portuguese languages, laboratory and clinical studies, and systematic reviews. Literature Review: Post and core are defined as prosthetic elements that seek intraradicular retention to support prosthetic crowns or unitary restorations. The ideal shape of the intraradicular retainer should supplement the dental remnant, allowing the shape of a prepared tooth to receive a prosthetic crown. In conjunction of the dental remnant, they are responsible for dissipating and absorbing the forces developed during the chewing cycles, without deformation or damaging the minimal cement layer. Conclusion: The evolution of endodontic therapy enables a restoration with greater safety of treated teeth. However, it is necessary to consider the remaining dental structure, mainly because the posts do not provide reinforcement, only retention and resistance to the prosthetic crown.

Objectives Periodontal ligament stem cells (PDLSCs) have an underlined significance as their high proliferative capacity and multipotent differentiation provide an important therapeutic potential. The integrity of these cells is frequently disturbed by the routinely used irrigative compounds applied as periodontal or endodontic disinfectants (e.g., hydrogen peroxide (H2O2) and chlorhexidine (CHX)). Our objectives were (i) to monitor the cytotoxic effect of a novel dental irrigative compound, chlorine dioxide (ClO2), compared to two traditional agents (H2O2, CHX) on PDLSCs and (ii) to test whether the aging factor of PDLSC cultures determines cellular responsiveness to the chemicals tested. Methods Impedimetry (concentration-response study), WST-1 assays (WST = water soluble tetrazolium salt), and morphology analysis were performed to measure changes in cell viability induced by the 3 disinfectants; immunocytochemistry of stem cell markers (STRO-1, CD90, and CD105) measured the induced mesenchymal characteristics. Results Cell viability experiments demonstrated that the application of ClO2 does not lead to a significant decrease in viability of PLDSCs in concentrations used to kill microbes. On the contrary, traditional irrigants, H2O2, and CHX are highly toxic on PDLSCs. Aging of PLDSC cultures (passages 3 vs. 7) has characteristic effects on their responsiveness to these agents as the increased expression of mesenchymal stem cell markers turns to decreased. Conclusions and clinical relevance While the active ingredients of mouthwash (H2O2, CHX) applied in endodontic or periodontitis management have a serious toxic effect on PDLSCs, the novel hyperpure ClO2 is less toxic providing an environment favoring dental structure regenerations during disinfectant interventions.

Nos tempos atuais, vivencia-se um aumento da expectativa de vida da população, com isso está sendo observado um maior desgaste da estrutura dentária. Quando há perda de esmalte dentário, ocorre uma exposição dos túbulos dentinários, causando desconforto e uma sensação dolorosa ao paciente chamada de hipersensibilidade da dentina. Os estímulos que desencadeiam essa sensação dolorosa aguda, provocada e de curta duração podem ser de origem química, térmica, evaporativa, tátil ou osmótica. Esse desgaste dentário tem a possibilidade de ocorrer em virtude de processos crônicos de dissolução ácida, sem presença de bactérias (erosão), do desgaste mecânico repetitivo (abrasão), da oclusão traumática (abfração) e de desgaste fisiológico (atrito), que são as lesões cervicais não cariosas e ocasionam um problema tanto estético quanto funcional. Este trabalho tem por finalidade mostrar os fatores etiológicos, classificação, aspectos clínicos, mecanismos de ação e opções terapêuticas das lesões cervicais não cariosas e da hipersensibilidade de dentina, possibilitando ao Cirurgião-dentista o conhecimento de um diagnóstico diferencial das lesões para que possa ter a melhor conduta perante o paciente. Foram observados fatores extrínsecos e intrínsecos associados, e que o trauma oclusal é o principal fator etiológico o qual predispõe o surgimento das demais lesões. Para esse estudo, foi feito um levantamento de referências bibliográficas em bancos de dados como PubMed/SciELO/BBO/Lilacs, juntamente com dois livros, durante o mês de maio de 2020, no intuito de proporcionar uma visão geral sobre o tema.

This research is focused on the screw-structure interaction under dynamic impulses aimed to the contact analysis of gap propagation at dental implant-abutment interface under dynamic loading. The purpose is to investigate the fracture mechanism that occurs during the screw penetration in a support and during the support vibration. Numerical Finite Element (FEM) analyses are calibrated through experimental laboratory measurements on support materials and screws typologies. Uncertainty due to the laboratory error propagation is investigated using Polynomial Chaos Expansion (PCE) of experimental measurements. The research is planned through the following steps: FEM calibration trough laboratory experiments on materials; laboratory experiments and material mechanics identification; uncertainty error propagation analysis through PCE expansion; fragility curves for numerical model calibration; FEM models calibration trough laboratory measurements on cycling loads. Therefore, the main purpose of the research activity, of which this article constitutes a preliminary and an explorative step, is to study a methodology that minimizes the local damage of the dental material due to the generation of micro-cracks following the implantation actions. Accordingly, in this paper, preliminary results are reported.

This study investigated the teaching of direct resin composite restoration repair in primary teeth in undergraduate dental programs within Brazil. A questionnaire relating to this topic was developed and e-mailed to 205 undergraduate dental schools between May and September 2019. Data obtained were analyzed descriptively. The response rate was 43.4% and out of those responding schools, 82% included this topic within their curriculum. Two of the most commonly reported reasons for teaching repair of resin composite restorations were dental structure preservation (95.9%), and reduction in the risk of pulp complications (71.2%). With regard to protocol for repair, few schools (24.7%) taught mechanical roughening of the resin portion to be repaired with diamond burs. Conversely, phosphoric acid etching was recommended by 87.7% of schools and 76.7% indicated adhesive application into prepared surface. The most commonly taught material for repair was conventional resin composite. The teaching the repair of failed resin composite restorations has been established within the curriculum of undergraduate dental programs in Brazil. However, there is no consensus for the clinical protocol for repair. Este estudo investigou o ensino do reparo de restauração direta de resina composta em dentes decíduos nos cursos de graduação em Odontologia no Brasil. Um questionário referente a este tópico foi desenvolvido e enviado por e-mail para 205 cursos de Odontologia entre maio e setembro de 2019. Os dados obtidos foram analisados descritivamente. A taxa de resposta foi de 43,4% e dos cursos respondentes, 82% incluíram esse tópico em seu currículo. As duas razões mais comumente relatadas para o ensino do reparo de restaurações de resina composta foram preservação da estrutura dentária (95,9%) e redução do risco de complicações pulpares (71,2%). No que diz respeito ao protocolo para reparo, poucos instituições (24,7%) ensinaram o desgaste mecânico da porção da resina a ser reparada com pontas diamantadas. Por outro lado, o condicionamento com ácido fosfórico da superfície preparada foi recomendado por 87,7% das instituições e 76,7% indicaram aplicação de adesivo na superfície preparada. O material mais comumente ensinado para reparo foi resina composta convencional. O ensino do reparo de restaurações de resina composta com falhas foi estabelecido dentro do currículo dos cursos de graduação em Odontologia no Brasil. No entanto, não há consenso sobre o protocolo clínico para reparo.

The aim of this study was to compare the effects of a single application of a new calcium mesoporous silica nanoparticle (Ca2+-MSN) versus other calcium and/or fluoride products against dental erosion. Enamel blocks were half-covered and assigned to six groups (n = 10): Ca2+-MSNs; casein phosphopeptide-amorphous calcium phosphate mousse (CPP-ACP); CPP-ACP/F− (900 ppm F−); titanium tetrafluoride (TiF4 1%); sodium fluoride (NaF 1.36%); and Milli-Q® water (negative control). A single application for each product was completed on the exposed areas of the blocks and were submitted to an erosive challenge. Differences in volumetric roughness (Sa), and tooth structure loss (TSL) by use of three-dimensional noncontact optical profilometry were evaluate. Scanning electron microscopy (SEM) was performed. Analysis of variance and Tukey’s test for Sa and the Kruskal-Wallis and Mann-Whitney U tests (p< 0.05) for TSL, respectively. Results: When evaluating Sa, all products presented differences in roughness when compared with the control group (p< 0.05) but not with each other (p > 0.05). However, when analyzing the TSL, it was observed that Ca2+-MSNs, TiF4, and NaF were more effective in preventing dental erosion versus CPP-ACP, CPP-ACP/F−, and Milli-Q® water (p< 0.05). In the SEM images, the negative control presented the worst loss of dental structure, with more porous enamel. Ca2+-MSNs were as effective as TiF4 and NaF to reduce the tooth structure loss.

Background After endodontic treatment, a proper restorative technique is necessary to ensure coronal seal and protection of residual dental structure; teeth which have lost two or more walls need to be restored with posts to increase retention and stability of final restoration. Posts can be distinguished in prefabricated and customized, which are manufactured by lost wax technique or CAD-CAM. Purpose Digital dentistry has been developed to increase workflow precision and to accelerate production process; use of CAD-CAM to realize customized posts was limited to scanning plaster models obtained from traditional impressions. Patients and methods In the reported case an intraoral scan was used to mill a post and core restoration on an endodontically treated inferior premolar; this operative protocol was based on previous in vitro experiments that confirmed the ability of 3shape Trios scanner to read post-space up to 9 mm in depth. Results The digital technique allows us to convert the concave surface of the root canal into the convex surface of the post, and realize an anatomical post and core that improves the biomechanics of the endodontically treated tooth reducing the possibility of root fractures. Conclusion The use of an intraoral digital scanner represents an opportunity for the clinician as it speeds up the production of an anatomical post and core restorations.

The quality of bone marrow preparation and sections of teeth depends on the preparation method. We investigated the posterior mandibles of male rats that were processed using a modified Bouin's solution (MBS) and stained with Harris' hematoxylin and eosin, and the results were compared to a routine decalcification process using 5% formal nitric acid. We found that MBS was applicable to both soft and hard components in bone tissues and sections of teeth. MBS provided good decalcification, which facilitated sectioning. The bone marrow specimens treated with MBS exhibited clearly distinguishable hematopoietic cells, clear tissue integrity and good cell preservation. Treatment with 5% formal nitric acid for 5 days caused degeneration, poor differentiation and poorer staining of hematopoietic components, and deteriorated soft and solid tissues in bone and sections of teeth compared to MBS treatment. MBS preserved cell and tissue integrity and good staining quality. MBS can be used for rapid preparation and diagnosis for pathology and toxicity studies.

Introduction: The presence of white spots due to dental fluorosis can cause aesthetic discomfort, being one of the factors for a search for dental treatment. Objective: Report a clinical case in which the aesthetic complaint was solved through the association of the dental bleaching to the microabrasion technique. Case report: Male patient, 13 years, attended to the Integrated Clinic of the School of Dentistry of the Federal University of Rio de Janeiro, with fluorosis, mainly in the antero-superior teeth and aesthetic complaint. Initially, it was made an immediate bleaching with hydrogen peroxide at 35%, in 3 sessions of 15 minutes each, to soften the disparity of shades between tooth-stain. The result was insufficient and the dental microabrasion technique was adopted. A pumice paste was applied together with gel of phosphoric acid at 37% under relative isolation, in a total of 8 applications (1 minute each). At the end of each application, it was made an abundant water washing, microengine mounted fine-grained disc polishing and topical application of neutral NaF2 in gel (4 minutes each application) to eliminate possible postoperative sensitivity. Conclusion: The dental bleaching and the microabrasion technique promoted satisfactory immediate clinical results that increased self-esteem of the patient in a minimally invasive way to dental structure. Introdução: A presença de manchas brancas por fluorose dentária pode causar desconforto estético, sendo um dos fatores para busca de tratamento odontológico. Objetivo: Relatar um caso clínico em que a queixa estética foi resolvida através da associação do clareamento dentário à técnica de microabrasão. Relato do caso: Paciente do sexo masculino, 13 anos, compareceu a Clínica Integrada da Faculdade de Odontologia da UFRJ, com fluorose, principalmente nos dentes ântero-superiores e queixa estética. Inicialmente, realizou-se clareamento imediato com peróxido de hidrogênio a 35%, em 3 sessões de 15 minutos, para suavizar a disparidade de tons entre mancha-dente. O resultado obtido foi insuficiente e a técnica de microabrasão dentária foi adotada. Uma pasta de pedra pomes foi aplicada juntamente com gel de ácido fosfórico a 37% sob isolamento relativo, perfazendo um total de 8 aplicações (1 minuto cada). Ao final de cada aplicação, foi realizada lavagem abundante com água, polimento com disco de granulação fina montado em micromotor e aplicação tópica de NaF2 neutro em gel (4 minutos cada aplicação) para eliminar possível sensibilidade pós-operatória. Conclusão: O clareamento dentário e a técnica de microabrasão promoveram resultados clínicos imediatos satisfatórios que elevaram a autoestima do paciente, de maneira minimamente invasiva para estrutura dentária.

Background Previous studies have shown that radiotherapy of the head and neck region can cause direct changes in dental structure. This study evaluated the effect of different solutions on the dentin chemical composition and collagen structure of irradiated dentin. Material and Methods Sixty maxillary canines were distributed in 2 groups (n=30): non-irradiated and irradiated (radiotherapy: X-rays of 6 MV in 30 cycles of 2 Gy to 60 Gy). The teeth were sectioned, sanded, and polished to obtain 3x3x2 mm fragments, which were redistributed in 3 subgroups (n=10) according to the treatment employed: chlorhexidine 2% (CL), chitosan 0.2% (QT), and 0.5 M carbodiimide (EDC). The samples were analyzed in FTIR at time zero (T0-control) and after 1 (T1), 3 (T3), and 5 (T5) minutes of immersion in the tested solutions. The data for the areas of the carbonate (C), amide I (AI) bands, and the ratio between the areas of the amide III/proline and hydroxyproline (AIII/PH) bands were analyzed using ANOVA and Tukey test (α=5%). Results QT showed lower C values at T1, T3, and T5 (P0.05). Conclusions Radiotherapy changes the secondary structure of collagen, and EDC was able to restore collagen integrity after 1 minute of immersion, without changing dentin inorganic composition. Key words:Radiotherapy, collagen, dentin, FTIR, chemical composition.

The origins of Homo , as well as the diversity and biogeographic distribution of early Homo species, remain critical outstanding issues in paleoanthropology. Debates about the recognition of early Homo , first appearance dates, and taxonomic diversity within Homo are particularly important for determining the role that southern African taxa may have played in the origins of the genus. The correct identification of Homo remains also has implications for reconstructing phylogenetic relationships between species of Australopithecus and Paranthropus , and the links between early Homo species and Homo erectus . We use microcomputed tomography and landmark-free deformation-based three-dimensional geometric morphometrics to extract taxonomically informative data from the internal structure of postcanine teeth attributed to Early Pleistocene Homo in the southern African hominin-bearing sites of Sterkfontein, Swartkrans, Drimolen, and Kromdraai B. Our results indicate that, from our sample of 23 specimens, only 4 are unambiguously attributed to Homo , 3 of them coming from Swartkrans member 1 (SK 27, SK 847, and SKX 21204) and 1 from Sterkfontein (Sts 9). Three other specimens from Sterkfontein (StW 80 and 81, SE 1508, and StW 669) approximate the Homo condition in terms of overall enamel–dentine junction shape, but retain Australopithecus -like dental traits, and their generic status remains unclear. The other specimens, including SK 15, present a dominant australopith dental signature. In light of these results, previous dietary and ecological interpretations can be reevaluated, showing that the geochemical signal of one tooth from Kromdraai (KB 5223) and two from Swartkrans (SK 96 and SKX 268) is consistent with that of australopiths.

Background and aims. The purpose of the study is to evaluate through a FEM (Finite Element Method) the effects of the rotation movement upon a complex structure (enamel– pulp -alveolar bone, PDL), for external load. Method. The progressive action of a fixed orthodontic device on three teeth: first molar, first and second premolar is modeled and simulated with the components placed on the buccal and palatal surfaces of the tooth. For the reproduction of a situation similar to the real one, the loading of the model was performed through a nodal force applied at a height of the crown, of various amplitudes, F = 1 N; 2, 3 and 4 N. The values of stress are: maximum stress of the whole structure and the shearing effect for the pulp. Results. The characteristics of the material are Young’s E modulus and Poisson’s ratio of the components of the modeled structure. The most stressed elements of the structure are the pulp and the ligament, revealed by von Mises stress. The elements of the structure are mainly stressed in fiber compression in the direction of the moment’s action given by the orthodontic forces and in fiber stretching in the opposite direction. Out of the orthodontic movements: translation, tipping, intrusion-extrusion , rotation is the most dangerous. Conclusions. The accumulated stress effect in the pulp becomes dangerous. The orthodontic movements given by dental force values higher than 1.5-2N are to be avoided.

Severe loss of dental structure can lead to decreased occlusal vertical dimension (OVD). Several procedures are recommended to restore OVD; for instance, temporary partial overlay-type prostheses can be used during the initial procedure. Aim: reporting the restoration of the decreased OVD based on the use of upper arch overlay prosthesis, temporary removable partial prosthesis and composite resin restorations in the lower arch. Case report: A 54-year-old male patient presented to the Oral Rehabilitation Clinic of Morgana Potrich Dentistry School (Mineiros City/GO, Brazil) complaining about aesthetic and functional deficiencies affecting his teeth. Extra-oral examination revealed deep nasolabial sulci, commissural lip pit and anterior mandibular projection. The intra-oral examination revealed tip-to-tip bite and significantly worn upper and lower teeth, as well as missing teeth. Thus, initial rehabilitation based on upper arch overlay, temporary removable partial denture and direct restorations in the lower arch was suggested. Functional molding was performed for model obtainment. Metric and phonetic techniques were combined in order to measure OVD and to assemble models in semi-adjustable articulators. Prostheses were installed after acrylization and, subsequently, the lower anterior teeth were restored. Conclusions: The use of overlay prosthesis enables initial OVD restoration. In addition, the combination of this procedure to direct restorations, or to temporary removable partial dentures, has restored oral aesthetics, function and comfort., A perda acentuada da estrutura dental pode causar diminuição da dimensão vertical de oclusão (DVO). Diversos procedimentos são indicados para o restabelecimento da DVO, e durante a conduta inicial, a prótese parcial provisória tipo overlay pode ser utilizada. Objetivo: Relatar o restabelecimento da DVO diminuída por meio da prótese tipo overlay no arco superior, prótese parcial removível provisória e restaurações em resina composta no arco inferior. Caso clínico: Paciente, gênero masculino, 54 anos, apresentou-se na Clínica de Reabilitação Oral da Faculdade de Odontologia Morgana Potrich (Mineiros/GO, Brasil), queixando-se da deficiência estética e funcional que acometia os elementos dentais. No exame extraoral observou-se sulcos nasolabiais profundos, depressão da comissura labial e a mandíbula projetada anteriormente. Durante o exame intraoral notou-se mordida topo a topo e desgaste acentuado nos elementos dentários superiores e inferiores além de regiões com ausências dentárias. Desta forma, foi proposto a reabilitação inicial por meio da overlay no arco superior, prótese parcial removível provisória e restaurações diretas no arco inferior. A moldagem funcional e obtenção dos modelos foram realizados. Para mensurar a DVO e montar os modelos em articulador semiajustável, as técnicas métrica e fonética foram associadas. Após acrilização, as próteses foram instaladas e posteriormente os dentes anteriores inferiores restaurados. Conclusões: O uso da prótese tipo overlay , auxilia no restabelecimento inicial da DVO. Além disso, a associação desse procedimento juntamente com restaurações diretas e prótese parcial removível provisória restabeleceu estética, função e conforto.

Personal identification in natural and manmade disasters can be made by using methods like DNA analysis, finger prints, carbon 14 enamel dating, rugoscopy, cheiloscopy, skull shape and size, dental structure chart and various denture labelling methods. Denture labelling systems have great significance in identifying people who have lost their memory or in state of unconsciousness or in identifying the human remains in natural calamity, disasters, accidents etc. A number of labelling systems are available and are broadly classified into either surface marking methods or inclusion methods. This article describes a unique method of labelling dentures using lead foil, linked with Aadhaar ID card (Unique Identification Number).

The purpose of this study is to identify the stress levels that act in inlay and onlay restorations, according to the direction and value of the external force applied. The study was conducted using the Finite Element Method (FEM) of three types of ceramics: pressed lithium disilicate and monolith, zirconia, and three different adhesive systems: self-adhesive, universal, and dual-cure cements. In addition to FEM, the inlay/onlay-dental structure interface analysis was performed by means of Scanning Electron Microscopy (SEM). The geometric models were reconstructed based on computer tomography images of an undamaged molar followed by geometrical procedures of inducing the inlay and onlay reconstructions. The two functional models were then simulated for different orientations of external force and different material properties, according to the considered adhesives and ceramics. The Scanning Electron Microscopy (SEM) was conducted on 30 extracted teeth, divided into three groups according to the adhesive cement type. Both FEM simulation and SEM investigations reveal very good mechanical behavior of the adhesive-dental structure and adhesive-ceramic interfaces for inlay and onlay reconstructions. All results lead to the conclusion that a physiological mastication force applied, regardless of direction, cannot produce a mechanical failure of either inlay or onlay reconstructions. The adhesive bond between the restorations and the dental structure can stabilize the ceramic restorations, resulting in a higher strength to the action of external forces.

Non-carious cervical lesions affect permanent teeth and cause the loss of healthy dental structure through a non-bacterial process. The occurrence of these lesions is multifactorial, although components of the occlusion are frequently associated. The objective of this article is to present a biomechanics of non-carious cervical lesions in finite element models. It is an integrative review of in silico studies carried out in PubMed, Scopus and Web of Science databases, using a PICo search strategy with descriptors. Studies in three dimensions carried out using finite element softwares that evaluated the biomechanical behavior of non-carious cervical lesions, without language restriction, published between 2000 and 2019 were included. Nine studies were eligible, analyzed and synthesized. The evidence indicates that when oblique occlusal forces are applied, the cervical zone of the dental elements receives greater stress, especially in the subsurface enamel. Furthermore, enamel can be more susceptible to stress than dentin, while V-shaped cervical lesions tend to receive more stress than U-shaped lesions, as well as the depth of these lesions potentially increases stress. Bone support and root morphology can modify the distribution of occlusal forces in dental elements. Thus, the biomechanical behavior of non-carious cervical lesions in finite element models is directly associated with oblique occlusal forces capable of generating tension in the cervical of dental elements. Keywords: Tooth Wear; Bite Force; Dental Stress Analysis; Review Literature as Topic.

Made available in DSpace on 2022-04-29T08:31:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-08-01 The loss of dental structure caused by endodontic treatment is responsible for a decrease in tooth resistance, which increases susceptibility to fracture. Therefore, it is important that minimally invasive treatments be performed to preserve the dental structure and increase the resistance to fracture of endodontically treated posterior teeth. To evaluate under axial loads, using the finite element method, the stress distribution in endodontically treated molars restored with both transfixed or vertical glass fiber posts (GFP) and resin composite. An endodontically treated molar 3D-model was analyzed using finite element analyses under four different conditions, class II resin composite (G1, control model), vertical glass fiber post (G2), transfixed glass fiber posts (G3) and vertical and transfixed glass fiber posts (G4). Ideal contacts were considered between restoration/resin composite and resin composite/tooth. An axial load (300 N) was applied to the occlusal surface. The resulting tensile stresses were calculated for the enamel and dentin tissue from five different viewports (occlusal, buccal, palatal, mesial and distal views). According to the stress maps, similar stress trends were observed, regardless of the glass fiber post treatment. In addition, for the G1 model (without GFP), a high-stress magnitude can be noticed in the proximal faces of enamel (7.7 to 14 MPa) and dentin (2.1 to 3.3 MPa) tissue. The use of transfixed glass fiber post is not indicated to reduce the stresses, under axial loads, in both enamel and dentin tissue in endodontically treated molar with a class II cavity. Department of Dental Materials and Prosthodontics Institute of Science and Technology São Paulo State University (Unesp), São José dos Campos Graduate Program in Dentistry Department of Dentistry University of Taubaté (UNITAU) Department of Dental Materials and Prosthodontics Institute of Science and Technology São Paulo State University (Unesp), São José dos Campos

Molar Incisor Hypomineralization (MIH) is a systemic defect on dental enamel, where the altered tissue may assume white, yellow or brown coloration, with a clear demarcation between the defect and the surrounding normal enamel. The etiologies have not been fully defined and early diagnosis is extremely important, since it can occur rapidly disintegrating dental structure, causing acute symptoms and making treatment difficult. Management of MIH is challenging, since the clinical appearance and individual need for treatment vary widely. To perform a literature review about MIH, highlighting the characteristics of the pathology, etiological factors, diagnosis and treatment, as well as reporting conduct used in a clinical case. A patient, 10 years old, male, norm systemic, attended at the Pedodontic Clinic, at the Federal University of Ceara-Sobral, in Brazil, was searching for dental care treatment. At the clinical examination, it was observed that the patient had an open bite and was a mouth breather. After radiographic taking and visual inspection, the clinical diagnosis of MIH was reached. The treatment plan was established, which consisted in definitive resin restoration composed of elements 16, 26, 36 and 46, for later orthodontic intervention. In the second treatment session, restoration was performed in composite resin of dental element 36. The restoration was performed with Resin Composite Opallis (A3), incrementally. Posterior finishing and occlusal adjustment were performed. Although the etiology is still uncertain, it is important to establish a correct and early diagnosis, so that the most appropriate treatment can be instituted, depending of the severity. Read more..... Key words: Tooth Demineralization, Etiology, Odontopediatric, Molar Incisor, Hypomineralization.

Background Maxillofacial injuries in children are rarer in proportion in comparison to adult facial injuries, and they constitute 1% to 15% of all facial bone fractures. The causes and incidence of maxillofacial injuries in children differ based on social, cultural, and environmental factors. Aim The purpose of this study is to investigate the etiology, epidemiology, and type of injury in pediatric facial injuries, as well as analyzing types of fractures, related injuries, and treatment options. Materials and methods The study obtained the approval of the local ethics board to include 55 pediatric patients in the age group of 0 to 18 years who received inpatient treatment or surgical interventions owing to maxillofacial trauma at an Esthetic, Plastic and Reconstructive Surgery Clinic between January 2016 and December 2018. The patients were examined under 5 groups based on their causes of injury: motorized vehicle accidents (MVA); bicycle; falls (from height or ground level); assault; firearm injuries. They were examined under 6 groups based on the location of their fractures: mandibula, maxilla, orbita, frontal bone, zygomatic arch, nasal bone. Results The study included 55 patients of the ages 0 to 18 with the mean age of 11.6 ± 3.2 years. Thirty-seven of the patients (67.2%) were male, whereas 18 (32.7%) were female. Among the causes of injury, the highest number of patients was 25 (45.4%) with MVA. The most frequent location of the fractures was the mandible. Conclusions Consequently, experiences regarding pediatric maxillofacial traumas are limited, and there is no complete consensus on treatment. In difference to the interventions in adults, the dental structure in pediatric patients need to be definitely considered, the least invasive intervention form should be preferred, and observation and follow-up should be practiced in minimally displaced fractures rather than surgical interventions.

INTRODUCTION: Caries oral disease occurring further destruction cause to dental tissues, by combination of several factors as modification of salivary pH and fluoride levels in salivary and dental plaque. In children pH and fluorideplays an important role in the mineralization of dental enamel. The concentration of fluoride in the enamel and dentin pulp area is relatively high. Fluoride plays a very important role, by tilting the process towards development of a dental structure more resistant to attack by acids and remineralization. OBJECTIVES: The objective of this research are to study the values of pH and fluoride in salivaryrespect to different dentition.METHODS AND POPULATION:28 patients of both sexes and ages 3 to 12 years who were attended in the dental clinic of Cordoba Catholic University. Design: Randomized, descriptive, cross-sectional study. Variables analyzed were samples of saliva and dental plaque pH and fluoride. The dentition was classified as temporary, permanent and mixed.RESULTS:The study showed high amount of fluoride in dental plaque good buffer capacity, with high levels of bicarbonate was observed. Positive correlation was founded between the levels of fluoride in dental plaque and salivary pH was found (r: 0.40, p < 0.05). The analysis of variance (ANOVA II) showed significant differences in the fluoride levelsin saliva respect to dental plaque in male 0.013 ± 0.002 vs 0.047 ± 0.016; p < 0.05; levels of fluoride in dental plaque in females regard males 0.017 ± 0.003 vs 0.047 ± 0.016p < 0.05.CONCLUSION:The analysis of samples of saliva and dental plaque of the patients studied, showed fluoride levels increased associated to dentition.

Enamel microstructure of 34 species in eight odontocete families is described and categorized according to structural complexity (from no or prismless enamel to highly arranged enamel in decussating layers), then correlated with parameters of ecology, life history, and occlusal function. Overall, more complex dental structure in extant and extinct cetaceans is associated with smaller, more numerous teeth in taxa that bite or grasp smaller, harder prey with longer, narrower jaws and have more oral processing. Enamel complexity loosely correlates with mechanical properties, but measurement of compressive strength is complicated by the presence of cementum overlying or in place of crown enamel. Given the presence of Hunter-Schreger bands and other indices of high microstructural complexity in archaic cetaceans (with presumed plesiomorphic characters), the absence of complex enamel, as well as more generally of gross dental form, signals a loss of complexity in various cetacean lineages. Nonetheless, it is difficult to draw robust or reliable inferences regarding either cetacean phylogeny or dental function given the pattern of presumed loss of tooth complexity, and the confounding presence of numerous exceptions (taxa with complex teeth despite limited use, or with thin, weakly developed enamel and soft, simple teeth despite high occlusal function). Although retention of a complex feature implies its continued adaptive value, and thus selection for the underlying genetic and developmental bases for that complexity, loss of complexity can simply follow absence of function. Loss of complex traits presumably relates to accumulated mutations and economic efficiency, but unfolds with no distinct pattern of distribution.

Objective. Polymerization of light-cured resin-based materials is well documented; however, the intensity of the activating light can be reduced by passage through air, dental structure, or restoration compromising the physical and mechnical properties of the restoration. The aim of this study was to evaluate the depth of cure of different light cured composite resins polymerized directly or transdental, through enamel and enamel/dentin tissues. Material and methods. Five composite resins were selected for this experiment: SureFil SDR, Dentsply (SDR), Filtek Supreme Plus, 3M ESPE (FSP), Aelite LS, Bisco (ALS), Filtek LS, 3M ESPE (FLS), and TPH, Dentsply (TPH). Thirty specimens of each material were prepared with 2- or 4-mm thickness. The specimens were light-cured (Elipar 2500, 3M ESPE) for 40 sec using three different protocols: direct or transdental, through a disc of enamel with 1 mm of thickness, and a disc of enamel and dentin with 2 mm of thickness. Eight Vickers microhardness (VH) measurements were taken from each specimen, four on top and four on bottom surface (Micromet, Buehler, 100 g per 15 sec). Data was analyzed with ANOVA three-way, Tukey HSD post-hoc (α = .05). Results. Bottom surfaces of specimens exhibited statistically significant lower Vickers microhardness than the top surfaces for all composite resin evaluated, regardless of the curing conditions, except for the SDR when direct light-cured. Transdental light curing through enamel/dentin layer, significantly decreased VH (P

Non-Carious Cervical Lesions (NCCL) are a current problem of multifactorial origin that is associated with the loss of vertical occlusal dimension, hypersensitivity, loss of teeth, fractures, and many other pathologies that affect the masticatory function of the oral cavity. Identification of the etiological factors of NCCL comprises a key piece for the solution of the problem. Based on clinical scientific evidence related with the diagnosis, a restorative treatment must be planned according to the loss of dental structure in order to return function and aesthetics. The purpose of this case report was to describe a 54-year-old male patient who was diagnosed with generalized NCCL combined with occlusal vertical dimension loss. The protocol of the treatment process is described. Las lesiones cervicales no cariosas (LCNC) son una problemática actual de origen multifactorial, la cual se ve asociada a la pérdida de dimensión vertical oclusal, hipersensibilidad, pérdida de dientes, fracturas y muchas otras patologías que afectan la función masticatoria de la cavidad bucal. La identificación de los factores etiológicos de las LCNC son piezas claves para la solución del problema. Basados en la evidencia científica clínica relacionado con el diagnóstico, se debe planificar un plan de tratamiento restaurativo que depende de la pérdida de la estructura dentaria para devolver la función y estética. El objetivo de este reporte de caso es describir a un paciente masculino de 54 años a quien se le diagnosticó LCNC generalizadas combinado con una pérdida de dimensión vertical oclusal. El protocolo de plan de tratamiento es descrito paso a paso.

Background: The aim of this study was to evaluate the effect of ceramic material types, degree of veneer translucency, and luting cement shades on masking the underlying dark dental substrate to achieve best esthetics. Materials and Methods: In this in vitro study, 56 specimens each of 0.5‑mm thickness were fabricated from two esthetic veneer materials Vita Enamic and Vita Suprinity, with two different translucencies, i.e., HT and T. To simulate the color of a dark underlying dental structure, background discs with C3 shade were fabricated using resin composite. The ceramic specimens with varying translucencies were cemented on the dark background of the resin composite with A1 and opaque white shades of resin luting cement. Color difference (ΔE) values from a reference color (A1 shade) were calculated using a spectrophotometer. The results were then statistically analyzed using three‑way ANOVA test (α = 0.05). Results: The ΔE values of both ceramic systems were affected by both the degree of veneer translucency (P = 0.00) and the luting agent shade (P = 0.016). The use of an opaque luting agent and T translucency resulted in a decrease in the ΔE* values for all ceramics tested, regardless to the material type. Suprinity and Enamic showed similarity in the masking ability of dark substrate after cementation. Conclusion: None of the 0.5‑mm veneers of the two ceramic systems could reach A1 shade without a detectable color difference after cementation. The change in degree of veneer translucency was more effective than the change in luting agent shade in masking the underlying dark substrate. Key Words: Ceramics, esthetics, resin cement

Objective: To assess the prevalence of dental erosion among basketball players who report consumption of carbonated beverages. Materials and methods : a cross-sectional study is proposed in a population of 60 basketball players aged 8 to 18 years, who perform physical activity more than 3 times a week and who consume energy drinks more than 3 times a week, without syndromes or systemic disease neither physical or intellectual disability. The participants were examined clinically by a single examiner regarding their upper anterior teeth through BEWE tooth erosion index and also by a questionnaire on knowledge and consumption of acidic beverages. Results : a high prevalence of dental erosion was observed (56.6%) in the evaluated population; 41.67% of participants preferred to consume hydrating drinks after the training day, with a high percen tage of carbonated beverages per day; where 71.67% know the negative effects of the consumption of these drinks. Conclusion : The presence of alterations in dental structure in the evaluated population is high.

Diabetes mellitus (DM) is a frequent worldwide disease. There are currently more than 46 million people who suffer this disease in North America and the Caribbean. The objective of this study was to determine if there is an association between DM and the presence of iron precipitates (Fe2+) in dental structure. The third molar was extracted for reasons that merit extraction from 40 individuals with and without DM to analyze dentin tissue. Horizontal and longitudinal slices of tooth samples were made and later stained with 10% potassium cyanoferrate. The samples were observed by optical microscope to identify basophilic elements. A nonparametric Spearman correlation was performed to find an association between the quantitative (gender, group, and dentinal tissue) and qualitative variables (gender). The Mann–Whitney U test was used to find differences in the means of the nonparametric variables in two different groups in relation to the P value (

Objectives: The aim of this study was to evaluate the influence of different restoration techniques (immediate dentin sealing (IDS) restoration techniques) and cavity designs on the cuspal deflection of posterior teeth that were restored with resin composite inlays. Methods: Sixty caries-free extracted maxillary premolars were selected and equally divided into two experimental groups. Group D1: MOD cavities were prepared. Group D2: MOD cavity with gingival steps. Each group was subdivided to three subgroups (n = 10) and restored as follows: inlay without IDS; inlay with IDS and adhesive system; inlay with IDS and adhesive system and low-viscosity resin. Cuspal deflection was measured with a micrometer. One-Way Analysis of Variance ANOVA was used to analyze the results. Results: Cavity design D1 showed the lowest cuspal deflection compared to cavity design D2. In group D1; Inaly without IDS showed the highest significant cuspal deflection (9.85 μm) followed by Inaly + IDS + Low viscosity resin (7.16 μm). The lowest value was obtained for Inaly + IDS group (4.76 μm) with significant difference between all tested restoration techniques. In group D2; Inaly without IDS showed the highest significant cuspal deflection (14.7 μm) followed by Inaly + IDS + Low viscosity resin (11.69 μm). The lowest value was obtained for Inaly + IDS (9.59 μm) with a significant difference between all tested restoration techniques. Conclusion: IDS and Protect Liner F allowed less cuspal deflection comparable with traditional technique. However, IDS restoration techniques did not decrease the cuspal deflection in case of more extensive loss of dental structure in the premolar teeth. Keywords: Cuspal deflection, Inlay, Cavity design, Restoration techniques

Dental erosion is a significant topic in medical literature, both for gastroenterology and dental medicine. Dental structure loss has a psychosocial and functional significance. The pathogenesis of dental erosion in patients diagnosed with gastroesophageal reflux disease (GERD) characterized by the presence of an acidic oral environment after reflux episodes, is not well understood. The present study was designed to observe the effect of low oral pH in time on natural surfaces including enamel and dentine, but also on materials used in treating these dental destructions such as composites and ceramics. The acidic oral environment was estimated in relation to salivary pH. In the dental laboratory, 5-mm2 and 1-mm composite pieces of thick enamel, dentine, Emax Ceramic and Nexco Ivoclar were cut in order to be analyzed using atomic force microscopy (AFM) and to observe the surface alterations. Gastric acid was collected and mixed with saliva until a pH value of 6.0 was obtained, in which the pieces were immersed for 24, 120, 240 h. Roughness of each surface was calculated at a microstructure and nanostructure level. The results showed significant alterations in enamel and dentine exposed to a lower pH level beginning even at a short immersion time, in comparison with composites and ceramics which had no alterations. In conclusion, multidisciplinary attention should be given to detect and manage acidity of the oral cavity caused by GERD, in order to prevent dental erosion.