Noncarious cervical lesions in the aging population analyzed through digital scanning: occlusal risk factors, dimensions, and morphology.

OBJECTIVES: To evaluate noncarious cervical lesions (NCCL) in older adults by analyzing each lesion's morphology, dimension, and occlusal risk factors using intraoral scanning and clinical evaluation. MATERIALS AND METHODS: Individuals over 60 treated at the School of Dentistry in Minas Gerais, Brazil, were invited to participate in this cross-sectional study. We clinically evaluated 1245 teeth for the presence of NCCL and dentin hypersensitivity (DH) in 53 individuals. Three-dimensional models were obtained using Omnicam, and occlusal risk factors were evaluated through the presence of wear facets, intense occlusal contacts, and interferences. The 3Shape 3DViewer software was used to classify NCCL morphology and to measure their height. NCCL depth, width, and area measurements were determined using ImageJ. Descriptive analyses were performed. The Kolmogorov-Smirnov test showed that quantitative data exhibited non-normal distribution. For bivariate analyses of quantitative data, the Mann-Whitney test was employed. The results were reported with mean, standard deviation, median, minimum, and maximum. For bivariate analyses of categorical data, the Pearson chi-square test was used. The results were reported with frequencies (counts) and percentages. A regression model evaluating the association between occlusal risk factors and the absence/presence of NCCL was built. RESULTS: Most participants were female (58.5%), with a mean age of 66. The frequency of NCCL was 28.27%, corresponding to 352 teeth. Of these, 68.18% exhibited saucer morphology and 31.82% wedge-shaped morphology. The frequency of DH was 13.92% in teeth with NCCL. Saucer NCCL exhibited significantly greater height (p = 0.02), while wedge-shaped lesions showed greater depth (p < 0.001). Also, teeth with NCCL had a higher proportion of wear facets (66.8%; p < 0.001), intense occlusal contacts (39.8%; p = 0.008), and occlusal interferences (21.9%; p = 0.05). The regression model showed that teeth with wear facets were 1.50 times more likely to exhibit NCCL than teeth without wear facets (p < 0.001). Teeth with intense occlusal contact were 1.22 times more likely to exhibit NCCL than teeth without intense occlusal contact (p = 0.031). CONCLUSIONS: NCCL is a common dental condition in the older adults evaluated in this study. Wedge-shaped NCCL exhibited greater depth, while saucer NCCL had more expressive height. Occlusal risk factors may represent a crucial mechanism for the occurrence of NCCL in this population. CLINICAL RELEVANCE: Understanding the mechanisms involved in developing NCCL is helpful in diagnostic and preventive practices. The study showed the importance of dental occlusion and characteristics of different NCCL morphologies that help the clinician in decision-making.

Photobiomodulation therapy and 3% potassium nitrate gel as treatment of cervical dentin hypersensitivity: a randomized clinical trial.

OBJECTIVES: This randomized controlled trial aimed to evaluate different protocols for dentin hypersensitivity treatment with low-power lasers and desensitizing agents, and the association between low-power lasers and desensitizing agents. MATERIALS AND METHODS: Fifty-four patients (303 teeth) were randomly allocated to three groups: G1, 3% nitrate potassium gel, UltraEZ (n = 17); G2, photobiomodulation therapy (PBM) with a low-level infrared laser (n = 17), 100 mW, spot size of 0.028 cm2, and dose of 1 J per point; and G3, nitrate potassium + PBM (n = 20). Treatments were applied to the buccal cervical region at intervals of 72 h, and all protocols were performed in three sessions. The patients' response to evaporative stimuli was rated using the visual analog scale (VAS). Re-evaluations were performed immediately after each application and 1 week, 1 month, and 3 months after treatment. A two-way repeated measures test and Tukey's post hoc test were used for multiple comparisons (α = 5%). RESULTS: There was a reduction in pain levels at the end of treatment in all groups. There were no significant differences in VAS score changes between the groups immediately after treatment and after the third month, compared to the baseline (p > 0.05). CONCLUSION: Under the limitations of this in vivo study, the proposed three-session protocol was effective in reducing dentin hypersensitivity after 3 months, regardless of the desensitization mechanism used. Conservative and long-term protocols are interesting for the control of pain caused by dentin hypersensitivity. CLINICAL RELEVANCE: The increase in cervical dentin hypersensitivity prevalence warrants easy-to-apply and long-lasting desensitizing protocols for pain control.

Prevalence of non-carious cervical lesions and orthodontic treatment: a retrospective study.

BACKGROUND: This study aimed to assess the distribution of non-carious cervical lesions (NCCLs) by tooth type, investigate the prevalence of NCCLs in patients undergoing orthodontic treatment, and identify the possible associated factors. MATERIAL AND METHODS: A total of 160 patients were enrolled in this retrospective study. Data on the following variables were collected from pre-and post-orthodontic treatment records: age, sex, Angle's malocclusion, facial pattern, number of activation sessions, compensatory treatment, and retreatment. Frontal, right and left lateral intraoral photographs of each patient were evaluated to identify the presence or absence of NCCLs in each tooth and assess the distribution of NCCLs in the 3840 teeth from the enrolled patients. Furthermore, patients were classified as NCCLs present, irrespective of the number of NCCLs on the teeth or NCCL absent. Bivariate and multivariate Poisson regression analyses with robust variance were used to assess the association between the NCCLs and each independent variable. Prevalence ratio and 95% confidence intervals were calculated and p < 0.05 was considered statistically significant. RESULTS: The prevalence of NCCLs before and after orthodontic treatment was 22.71% and 30.91%, respectively. Premolars were the most affected teeth, followed by the first molars, canines, and incisors. After statistical analysis, age was found to be the variable factor that influenced the prevalence ratio, with NCCL being the most prevalent when orthodontic treatment was performed in adulthood. CONCLUSIONS: Premolars were most commonly affected by NCCLs. Furthermore, age seemed to contribute to the increased prevalence of NCCLs in adults undergoing orthodontic treatment.

Influence of non-carious cervical lesions, bone attachment level, and occlusal load on the stress distribution pattern in maxillary premolars: finite element analysis

This study aimed to evaluate the influence of different bone attachment levels and occlusal loads on the stress distribution pattern of maxillary premolars with or without non-carious cervical lesion (NCCL), before and after restoration with composite resin by three-dimensional (3D) finite element analysis. From the healthy model, NCCL models were produced and the cavity was restored with composite resin. Models with vertical and horizontal bone loss were also made. For each model, three types of occlusal loads were simulated (100 N): vertical load (VL), buccal load (BL), and palatal load (PL). After processing the models, the data were obtained in MPa for the criteria of Maximum Principal Stress (for all structures) and Minimum Principal Stress (for cortical and medullary bones). Stress values were collected for a node on the cervical buccal surface (Maximum Principal Stress) and the buccal crestal bone (Minimum Principal Stress). As a result, the different bone attachment levels did not affect stress distribution at the amelodentinal junction. The buccal load promoted a higher concentration of compressive stress on the buccal bone surface and the palatal load resulted in greater tensile stress in the buccal cervical third of the tooth. The concentration of tensile stress in the buccal cervical third was exacerbated by the presence of NCCL and it was similar to the healthy and restored models. It can be concluded that stress concentration at the bone level does not depend on the presence or absence of NCCL and the restoration procedure but it is related to the type of occlusal load. However, the presence of NCCL promoted a higher stress concentration in the cervical region, especially when combined with oblique occlusal loads.

Brazilian dentists' perception of dentin hypersensitivity management.

The aim of this study was to investigate how Brazilian dentists perceive and manage dentin hypersensitivity (DH) in their clinical routine. A 13-item questionnaire-based survey was developed and sent electronically to a convenience sample of dentists. The questionnaire assessed the personal and dental practice characteristics of the sample, the occurrence of DH in their daily clinical practice, and management strategies. The data were analyzed descriptively and together with the chi-square test (a = 0.05). A total of 353 responses were obtained from September 2017 to March 2018. Of all the respondents, 62% were females, 49.9% reported fewer than five years of dental practice, and 70.5% were self-identified as private practitioners. Most of the dentists reported an estimated frequency (30-60%) of patients with DH in their practice. The most frequently cited (91.79%) trigger of DH was air blast and/or scratching with a probe. The first-choice strategy to manage DH was a dentin desensitizer (48.16%). The number of years in clinical practice did not influence DH relapse frequency (p = 0.76) significantly, or consider DH treatment as a problem (p = 0.22). The present findings indicate that, regardless of clinical experience, dentists in Brazil still consider DH management a challenge in their daily dental practice. In addition, the results suggest that guidelines should be developed to disseminate the available knowledge regarding this condition in ways that may influence decision-making processes among practitioners.

Limited Evidence Suggests That Many Types of Desensitizing Toothpaste May Reduce Dentin Hypersensitivity, but Not the Ones With Strontium or Amorphous Calcium Phosphate.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Effect of desensitizing toothpastes on dentine hypersensitivity: A systematic review and meta-analysis. Hu M-L, Zheng G, Zhang Y-D, Yan X, Li X-C, Lin H. J Dent (2018)75:12-21. SOURCE OF FUNDING: The authors reported that this research did not receive any specific funding from the public, commercial, or not-for-profit sectors. TYPE OF STUDY/DESIGN: Systematic review with meta-analysis of data.

A long-term evaluation of experimental potassium oxalate concentrations on dentin hypersensitivity reduction: A triple-blind randomized clinical trial.

OBJECTIVE: The aim of this split-mouth, triple-blind, randomized clinical trial was to evaluate the long-term clinical efficacy of experimental potassium oxalate concentration (10%) in relieving dentin hypersensitivity (DH), after a four-session application protocol. METHODS: Potassium oxalate gels with different concentrations (5 and 10%) were randomly assigned to half of the 31 patients from the sample in a split-mouth design. The desensitizers were applied following a four-session protocol, one session every 48 h. The primary outcome was the assessment of pain level with the visual analog scale (VAS, 0-10), at baseline, immediately after each desensitizing session, and also after the seventh day and along 1-,3-, 6-, 9- and 12-months follow-ups. Statistical analyses were performed using Friedman repeated measures and Wilcoxon signed rank tests (α = 0.05). RESULTS: For both groups, the minimum of three sessions were required for the achievement of lower DH levels. Regardless of the concentration, the desensitizing effect was maintained all the way to the end of the 6-month follow-up. The 10%-potassium oxalate group was more effective for both 9 and 12-months follow-up periods (p < 0.001). No complications and adverse effects were observed. CONCLUSIONS: When a four-session protocol is applied, both concentrations of potassium oxalate (5 and 10%) proved to be effective on DH reduction for up to six months. However, the higher concentration promoted better long-term results. CLINICAL SIGNIFICANCE: The DH is an increasing condition in clinical practice, which affects the patient's life quality. This study provides primary clinical evidence, suggesting that multiple application sessions and higher concentrations of potassium oxalate may result in maintenance of the desensitizing effect for more extended periods. Trial registered under number: ClinicalTrials.gov NCT03083496.

Four-Session Protocol Effectiveness in Reducing Cervical Dentin Hypersensitivity: A 24-Week Randomized Clinical Trial.

Objective: A single-blind randomized clinical trial was conducted to evaluate the effectiveness of desensitizing agents with different action mechanisms in reducing cervical dentin hypersensitivity (CDH) after four application sessions, with 24-week follow-up. Materials and methods: Sixty patients with CDH were selected in the study and were allocated in three groups of treatment: Desensibilize KF 2%, Clinpro XT Varnish, and Photon Lase III (100 mW, 4 J/cm2-1 J/cm2 each point, 10 sec per point with wavelength of 808 nm). There were four application sessions performed, with a 48-h interval between each one. The evaporative stimuli and visual analog scale were used to evaluate the CDH level at baseline, immediately after treatment, and at 2, 4, 8, and 24 weeks after the application. Mixed-model effects test was used for comparison (α = 0.05).Results: All three groups showed significant reduction in CDH from baseline to each all-subsequent follow-up. All the groups maintained the CDH reduction, and presented no statistical differences between each other after treatment (p = 0.885), 2 (p = 0.857), 4 (p = 0.928), 8 (p = 0.206), and 24 weeks (p = 0.073) of follow-up.Conclusions: The four-session protocol was an effective approach in reduction of CDH (even after 24 weeks), regardless of desensitization mechanism.

Influence of anterior load and restorative procedure on maxillary incisors with different cervical wear morphologies / Influência do procedimento restaurador e de contato anterior em incisivos superiores com diferentes morfologias de desgaste cervical

The aim of this study was to evaluate the influence of different anterior load type and restorative procedure on stress distribution of maxillary incisors with different noncarious cervical lesions (NCCLs) morphologies. Three-dimensional models of a maxillary incisor were generated. Beyond the sound model (SO), five NCCLs morphologies were simulated: shallow (SH), notched (NO), concave (CO), wedge-haped (WS) and irregular with dual center (IR' and IR"). Composite resin restoration of all the models was simulated (R). Two different anterior loads were applied: 100N on palatine middle third (ML) and 500 N on palatine incisal third (IL). The data were obtained in MPa using the Maximum Principal Stress and Von Mises criteria and the statistical analysis was performed (paired t-test with 95% confidence level). The IL provided higher compressive stress than ML, mainly on WS (-136.3MPa), IR" (-117.5) and NO (-71.1 MPa). The highest tensile stress found within the restored models was on NOR with IL (19,1 MPa). The Von Mises results showed higher stress concentration on non-restored and IL models (p<0.001). The anterior load type and restorative status were determinant factors on stress distribution pattern changes, whereas NCCLs morphologies had little influence in maxillary incisors.

O objetivo deste estudo foi avaliar a influência de diferentes tipos de contatos anteriores e procedimentos restauradores na distribuição de tensões de incisivos superiores com diferentes morfologias de lesões cervicais não-cariosas (NCCLs). Modelos tridimensionais de um incisivo central superior foram gerados. Além do modelo hígido (SO), foram simuladas cinco morfologias de NCCLs: rasas (SH), entalhadas (NO), côncavas (CO), em forma de cunha (WS) e irregulares com centro duplo (IR' e IR''). Restauração com resina composta em todos os modelos foi simulada (R). Dois contatos anteriores diferentes foram aplicadas: 100N no terço médio palatino (ML) e 500N no terço incisal palatino (IL). Os dados foram obtidos em MPa utilizando os critérios de Tensão Máxima Principal e de Von Mises e a análise estatística foi realizada (teste t pareado com nível de significância de 95%). A IL proporcionou maior estresse compressivo que ML, principalmente em WS (-136,3MPa), IR "(-117,5) e NO (-71,1 MPa). A maior tensão de tração encontrada nos modelos restaurados foi na NOR com IL (19,1 MPa). Os resultados de Von Mises mostraram maior concentração de estresse nos modelos não restaurados e IL (p <0,001). O tipo de contato anterior e a presença de restauração foram fatores determinantes nas alterações do padrão de distribuição de estresse, enquanto as morfologias dos NCCLs tiveram pouca influência nos incisivos superiores.

Relationship between noncarious cervical lesions, cervical dentin hypersensitivity, gingival recession, and associated risk factors: A cross-sectional study.

OBJECTIVES: The aim of this study was to evaluate the risk factors associated with noncarious cervical lesions (NCCLs), cervical dentin hypersensitivity (CDH), and gingival recession (GR), besides the relationship among these conditions in a specific Brazilian sample population. METHODS: 185 patients who attended the "Ambulatory Program for Rehabilitation of Patients with Noncarious Cervical Lesions and Cervical Dentin Hypersensitivity" were evaluated, and 5180 teeth were analyzed. The subjects filled out a form and a calibrated examiner performed the clinical exams to determine the presence of NCCLs, CDH, and GR. NCCLs were classified according to their morphology and depth, CDH levels were evaluated according to air stimuli response, and GRs were categorized according to Miller's classification. The association of the risk factors with NCCLs, CDH, and GR was determined with the Mann-Whitney U test and multiple linear regression. For the correlations, the Spearman test was used with a 95%-confidence level. RESULTS: The NCCLs, CDH, and GR distributions within the study were 88.1%, 89.1%, and 59.4%, respectively. Maxillary premolars were the most affected by all three conditions. A positive correlation was found between age, NCCLs, and GR; between NCCLs and CDH; CDH and GR; GR and NCCLs. Age, gender, oral hygiene, gastroesophageal diseases, and occlusal trauma were significantly associated with the presence of all three conditions. CONCLUSIONS: The NCCLs and GR distributions increased with age; NCCLs, CDH, and GR had positive correlation; the lesions' depth and morphology contributed to high levels of sensitivity and severity of recessions; age, gender, gastric disease, and occlusal trauma were relevant factors for the occurrence of NCCLs, CDH, and GR. CLINICAL SIGNIFICANCE: The increasing distribution of NCCLs, CDH, and GR is closely associated with people's lifestyles. Thus, it is important for the clinicians to recognize the etiological factors and their most relevant associations to prevent and control such alterations, in order to improve the population's quality of life.

Esthetic rehabilitation with minimally invasive feldspathic ceramic veneers: 30 months of clinical follow-up / Reabilitação estética com facetas em cerâmicas feldspáticas minimamente invasivas: 30 meses de acompanhamento clínico

Diastemas among maxillary incisors and gingival contour disharmony are common findings among patients in dental practice. Ceramic veneers are indicated for esthetic rehabilitation of anterior diastemas due their predictable results, optical characteristics, fracture resistance and tooth structure conservation. However, because it is a friable material and have a brittle behavior, fractures occurrences are related to trauma, oclusal overload, parafunctional habits and material fatigue. This article describes 30 months follow-up of an esthetic and functional rehabilitation diastemas closure using feldspathic veneers associated with periodontal surgery and a ceramic repair with composite resin. Gingivectomy and frenectomy needs were found and the surgical procedures performed guided by new anatomic aspects of the crowns. Mock-up was performed after waxing and reverse planning. All anterior teeth underwent minimally invasive preparation. Feldspathic ceramic veneers were made, tried using try in paste and luted with light-cure resin cement. After 24 months, a fracture occurred on the right maxillary canine veneer. The ceramic restoration repair was performed with nano-hybrid composite resin, after the conditioning with 5% hydrofluoric acid, 37% phosphoric acid and silane couple agent. The combination between ceramic veneers and gingivectomy enables to obtain conservative treatments and esthetic success. After six months of the repair, resulting 30 months of follow-up, the anterior restorations were aesthetically and functionally satisfactory.

Presença de diastemas entre os incisivos superiores e desarmonia do contorno gengival são achados comuns entre os pacientes atendidos na rotina clínica. Facetas cerâmicas são indicadas para reabilitação estética de diastemas anteriores devido a previsibilidade de resultados, características óticas, resistências à fratura e conservação de estrutura dentária. Entretanto, por este ser um material frágil e apresentar comportamento friável, fraturas podem estar relacionadas a episódios de trauma, sobrecarga oclusal, hábitos parafuncionais e fadiga do material. Este artigo descreve um acompanhamento clínico de 30 meses de reabilitação estética e funcional de fechamento de diastema utilizando facetas minimamente invasivas confeccionadas com cerâmicas feldspáticas associadas à cirurgia periodontal e necessidade de reparo da cerâmica com resina composta. A indicação de plastia gengival e frenectomia foram constatadas e o procedimento cirúrgico guiado pelo planejamento da nova anatomia das coroas dentárias. Todos os dentes anteriores superiores foram minimamente preparados. O mock-up foi realizado depois do enceramento e do planejamento reverso. Facetas em cerâmicas feldspáticas foram confeccionadas, a cor do cimento resinoso selecionada com pastas testes e a cimentação concluída com cimento de polimerização exclusiva física. Depois de 24 meses de acompanhamento, ocorreu fratura da faceta do canino superior direito. O reparo da restauração cerâmica foi realizado com resina nanohibrida, depois da cerâmica condicionada com ácido fluorídrico 5%, ácido fosfórico 37% e aplicação de agente de união silano. A combinação entre facetas cerâmicas e cirurgia de plastia gengival permite alcançar tratamento conservador e sucesso estético. Posteriormente seis meses do reparo, resultando em 30 meses de acompanhamento clínico, as restaurações anteriores permaneciam estética e funcionalmente satisfatórias.

Restorative material and loading type influence on the biomechanical behavior of wedge shaped cervical lesions.

OBJECTIVES: To evaluate the influence of restorative materials used on the rehabilitation of MOD cavities and loading type, on biomechanical behavior of wedge-shaped (WS) lesions in endodontically treated maxillary premolars. The investigation was conducted by 3D finite element analysis (FEA) and strain gauge test. MATERIALS AND METHODS: Six models were generated, with MOD cavities and endodontic treatment: A (MOD amalgam restoration), R (MOD composite restoration), AL (A + cervical lesion (L)), RL, ALR (A + cervical lesion restored with composite (LR)), and RLR. Each model underwent two compressive loading (100N): axial and oblique-45° angle to the long axis on the buccal cusp. The models were analyzed by von Mises criteria. For strain gauge test, 14 standardized maxillary premolars were treated according to the groups described for FEA. Two strain gauges were bonded on each sample submitted to compressive loading in a mechanical testing machine. RESULTS: A presented higher stress concentration and strain values than R. Oblique loading promoted highest stress concentration and strain rates for all groups. ALR and RLR presented similar stress-strain distribution pattern when compared to A and R. CONCLUSION: The interaction between MOD cavity restored with amalgam and oblique loading propitiated the highest stress concentration and strain values on cervical region and WS lesion. CLINICAL RELEVANCE: The MOD cavity restored with composite resin is a better option than amalgam to improve the biomechanical behavior of wedge-shaped lesion, avoiding dental failure. In addition, the occlusal interferences must be removed, allowing homogeneous contact distribution and preventing WS lesion progression.

Multidisciplinary treatment of congenitally missing maxillary lateral incisors: a case report / Tratamento multidisciplinar de agenesias de incisivos laterais superiors: relato de caso

Congenital tooth agenesis and tooth loss due to dental traumatism are some of the most common causes leading to rehabilitation of young patients with dental implants. The success of treating congenitally missing teeth with implant-supported prosthesis is no more guided only by osseointegration criteria. Nowadays the successful rehabilitation of these cases involves the adequate installation of dental implants with suitable prosthetic contour, color, and emergence profile closer to that found in natural dentition. Several treatment options are available for restoring patients with congenitally missing teeth such as maxillary lateral incisors. Fixed prosthodontics and orthodontics managements are considered acceptable treatment protocols. However, the gold standard rehabilitation of congenitally missing maxillary incisors is performed with implant-based prosthesis since no tooth wear neither extensive tooth movements are necessary. The present paper reports the treatment of a young adult woman with congenitally missing maxillary lateral incisors who underwent orthodontic treatment for improvement of teeth alignment and occlusal balance previous to dental implant surgery. This treatment also allowed appropriate space for the future lateral incisors crowns. Then, Morse-type conical implants were positioned and prosthetic abutments installed. Ceramic laminates were planned on central incisors in order to improve anterior aesthetics. All-ceramic crowns and laminates were made using lithium dissilicate-based ceramic (e-Max Press). The multidisciplinary association of orthodontic, implant and prosthetic techniques resulted in successful functional and aesthetic rehabilitation of the case, which was maintained after 1 year follow up.

Agenesias e perdas dentárias devido a traumatismos estão entre as principais causas de reabilitações de pacientes jovens com implantes dentários. O sucesso do tratamento de agenesias com implantes osseointegrados não se limita mais à osseointegração exclusivamente. Atualmente, o sucesso da reabilitação destes casos envolve a correta instalação de implantes que favoreçam a confecção de uma prótese com cor, forma e perfil de emergência o mais semelhante possível aos dentes naturais. Os cirurgiões-dentistas têm várias opções para tratar casos de agenesias como as de incisivos laterais superiores. Próteses fixas convencionais e movimentação ortodôntica são considerados protocolos de tratamento aceitáveis. Entretanto, agenesias de incisivos laterais superiores são reabilitadas satisfatoriamente com próteses sobre implantes uma vez que extensas movimentações ou desgastes dentários são necessários. O presente caso relata o tratamento de uma paciente jovem com agenesia dos incisivos laterais que havia feito tratamento ortodôntico para correção do posicionamento dentário e equilíbrio dental antes de se submeter à cirurgia para instalação de implantes. O tratamento ortodôntico também favoreceu a obtenção de espaço apropriado para instalação das coroas dos incisivos laterais. Posteriormente, implantes cônicos com plataforma protética tipo cone morse foram instalados e pilares selecionados. Laminados cerâmicos foram planejados para os incisivos centrais com objetivo de se promover um resultado final mais harmônico e estético. As coroas em cerâmica pura e laminados foram confeccionados com cerâmica a base de dissilicato de lítio (e.Max Press). A associação multidisciplinar entre tratamento ortodôntico, implantes e próteses sobre implantes resultou no sucesso funcional e estético da reabilitação do presente caso com acompanhamento clínico de uma ano.

Influence of non carious cervical lesions depth, loading point application and restoration on stress distribution pattern in lower premolars: a 2D finite element analysis / Influência da profundidade da lesão cervical não cariosa, ponto de aplicação de carga e restauração no padrão de distribuição de tensões em pré-molares inferiores: 2d-análise por elementos finitos

The aim of this study was to analyze the biomechanical behavior of lower premolars regarding the non-carious cervical lesion (NCCL) depth, load type and restoration status, using finite element analysis. Twodimensional virtual model simulating a healthy lower premolar were created using the CAD software. Based on this image, five models were generated: healthy (H), three types of NCCLs: small lesion (SL ­ 0.5 mm deep), medium lesion (ML ­ 1.0 mm), deep lesion (DL ­ 1.5 mm), and restored lesion (RL). The models were export to a CAE software (ANSYS Finite Element Analysis Software), the areas of all structures were plotted and each model was meshed using a control mesh device. All of the virtual models were subjected to two occlusal load types, (100N each): occlusal load (OL) and buccal load (BL) on buccal cusp. The magnitude and the stress distribution were obtained using the von Mises and maximum principal stress criteria (1), in MPa. The quantitative analysis of stress (MPa) was identified at three points of the NCCLs: enamel surface on its upper wall , dentin at the bottom wall and dentin on the lower wall. The results showed a direct relation between sequential removal of cervical structure and higher stress concentration for any groups and for both loads types. For OL the highest value of stress was 8.8 MPa for DL on upper wall of NCCLs.The BL exhibited higher stress values in comparison to the OL for all models.In addtion, the BL was responsible for providing the highest stress accumulation on the bottom wall, 38.2 MPa for DL. The restoration with composite resin was able to restore a stress distribution close to the healthy model, for both load types. In conclusion, the extent of non-carious cervical lesion and loading conditions influenced the stress distribution pattern of lower premolar. The outer load seems to be more critical in affecting the biomechanical behavior of lower premolars, regardless of the lesion size. The restoration of NCCLs with composite resin appears to recover the biomechanical behavior, similar to healthy model.

O objetivo desse estudo foi analisar o comportamento biomecânico de pré-molares inferiores em relação a profundidade da lesão cervical não cariosa (LCNC), tipo de carregamento e condição da restauração, utilizando a análise por elementos finitos. Modelo virtual bidimensional simulando um pré molar inferior hígido foi criado utizando o software de CAD.A partir dessa imagem, cinco modelos foram gerados: hígido (H), três tipos de LCNCs-lesão rasa (SL-0.5 mm de profundidade), lesão média (ML-1.0mm), lesão profunda (DL-1.5mm), e lesão restaurada (RL). Os modelos foram exportados para o software de CAE (ANSYS Software de Análise por Elementos Finitos), as áreas de todas as estruturas foram plotadas e cada modelo foi malhado utilizando um dispositivo controle de malha.Todos os modelos virtuais foram submetidos a dois tipos de carregamento oclusal (100N cada): carregamento oclusal (OL) e carregamento externo (BL) na cúspide vestibular. A intensidade e a distribuição das tensões foram obtidas utilizando os critérios de von Mises e tensão máxima principal (1),em Mpa. A análise quantitativa das tensões (MPa) foi identificada em três pontos das LCNCs: parede superior em esmalte, parede de fundo em dentina e parede inferior em dentina. Os resultados apresentaram uma relação direta entre a remoção sequencial de estrutura na região cervical e os maiores valores de concentração de tensões para todos os grupos e para os dois tipos de carga. Para OL, o maior valor de tensão foi 8.8 MPa para DL na parede superior da LCNCs. O BL exibiu maiores valores de tensão em comparação ao OL para todos os modelos. Além disso, BL foi responsável por promover o maior acúmulo de tensão na parede de fundo, 38.2 MPa para DL. A restauração com resina composta foi capaz de restaurar uma distribuição de tensões similar a do modelo hígido, para ambos os tipos de carga. Em conclusão, a extensão da lesão e o tipo de carregamento influenciaram no padrão de distribuição de tensões de pré-molares inferiores. A carga externa parece ser mais crítica para afetar o comportamento biomecânico de pré-molares inferiores, independente do tamanho da lesão. A restauração das LCNCs com resina composta, parece recuperar o comportamento biomecânico similar ao do modelo hígido.

Enxerto de tecido conjuntivo subepitelial otimizando a reabilitação oral com implantes osseointegrados / Connective tissue graft improving implant oral rehabilitation

A estética tem sido um fator indispensável, tanto no direcionamento quanto no desenvolvimento da Odontologia, assim como na Implantodontia. Além da boa qualidade e anatomia da prótese que substituirá o dente perdido, a aparência saudável e harmônica do tecido peri-implantar é preponderante no tratamento reabilitador final. A estratégia de substituição de dentes anteriores com próteses sobre implantes pode envolver procedimentos multidisciplinares. As técnicas cirúrgicas de plástica peri-implantar são amplamente aplicadas com previsibilidade naquelas situações clínicas que demandam volume, forma e qualidade dos tecidos moles ao redor dos implantes. Sob esse ponto de vista, o enxerto de tecido conjuntivo subepitelial tem sido empregado com alto índice de sucesso, para obtenção de estética, função e saúde da mucosa peri-implantar.

Substituição de implante perdido por peri-implantite e reabilitação multidisciplinar em 18 meses: acompanhamento de um ano / A 18-month multidisciplinary rehabilitation period for a dental implant replacement due to peri-implantitis – 1 year follow-up

O presente caso clínico relata a perda de um implante devido à peri-implantite, cuja ocorrência foi favorecida pelo mau posicionamento do mesmo. Dessa forma, a coroa e o implante foram removidos, por ausência de possibilidade de outro tratamento mais conservador. Com o auxílio de técnicas cirúrgicas de enxerto ósseo (autógeno e xenógeno), enxerto gengival (conjuntivo subepitelial), tratamento ortodôntico e confecção de novas próteses, a saúde e a estética da paciente foram restabelecidas. Para a substituição, foi utilizado um implante cone-morse, amplamente utilizado em áreas estéticas atualmente. O tratamento durou 18 meses, atingindo as expectativas da paciente. Concluiu-se que a abordagem multidisciplinar e a comunicação entre os profissionais são essenciais para o sucesso do tratamento, uma vez que a instalação de implantes, sem planejamento protético minucioso, pode resultar em uma quantidade inumerável de problemas e complicações, no que diz respeito aos resultados cirúrgicos e protéticos esperados.

This case reports on the loss of a dental implant due to peri-implantitis favored by its malpositioning. In this way, the defi nitive crown and implant were removed because a more conservative treatment was not possible. With the aid of surgical techniques as bone grafting (autogenous and xenogeneic), gingival grafts (subepithelial connective tissue), orthodontic treatment and fabrication of new prostheses, the health and esthetic aspects were retrieved. A new dental implant (Cone Morse type) was inserted as advocated for esthetic regions. After 18 months, patient expectations were achieved. It can be concluded that a multidisciplinary approach and communication among different specialists are fundamental for a successful treatment once incorrect implant placement can generate a myriad of problems and complications regarding the surgical and prosthetic expected outcomes.

The effects of non carious cervical lesions - morphology, load type and restoration - on the biomechanical behavior of maxillary premolars: a finite element analysis / OS efeitos das lesões cervicais não cariosas ­ morfologia, tipo de carregamento e restauração - no comportamento biomecânico de pré-molares superiores: análise por elementos finitos

The aim of the present study was to analyze the effects of different types of non-carious cervical lesions (NCCLs) and their morphologies in premolars, restored (or not) with composite resin, on the application three occlusal loadings. The hypothesis was that differing NCCL morphologies, loading types and restoration with composite resin affect stress distribution patterns. A two-dimensional linear Finite Element Analyses (FEA) simulated a healthy tooth model (H) with dental structures including: dentin, pulp, enamel, periodontal ligament, cortical bone, and trabecular bone. Three NCCL morphological models were examined: Mixed (MI), Sauce (SA) and Wedged-shape (WS). All types of lesions were analyzed with and without restoration. The models were considered homogeneous and elastic. In each model three load types: 100N: vertical load (VL), buccal load (BL) and palatine load (PL) were applied. The Maximum Principal Stress values were analyzed. The quantitative analysis of stress (MPa) was identified at five points of the NCCLs according to the morphology of the lesion type: initial point, superior wall, center of lesion, inferior wall and final point. It was found that NCCLs restored with composite resin exhibited stress distribution patterns similar to the healthy tooth model, independent of morphology and load. The Palatine Load was responsible for providing the highest values of accumulated tensions on the NCCL. The highest values of tensile stress on NCCL areas were found in the models without composite resin restoration, which had received PL. It was concluded that the different NCCL morphologies had little effect on stress distribution patterns. The major factors that affected the biomechanical behavior of premolars presenting NCCL were load type and the presence of composite restoration.

O objetivo desse estudo foi analisar a influência de diferentes morfologias de lesões cervicais não cariosas (LCNCs) em pré-molares superiores restaurados ou não com resina composta, aplicando três diferentes carregamentos oclusais. A hipótese é que a morfologia, o tipo de carregamento e a restauração influenciem no padrão de distribuição de tensão. Através do método de elementos finitos, foram simulados modelos bidimensionais, homogêneos, lineares e elásticos. O modelo do dente hígido (H) foi representado com as seguintes estruturas: dentina, polpa, esmalte, ligamento periodontal, osso cortical, osso trabeculado e posteriormente simulou-se três morfologias de LCNCs: Mista(MI), Arredondada (SA) e em forma de Cunha (WS). Todos os tipos de lesão foram analisados com a presença e ausência da restauração. Em cada modelo foram aplicados três diferentes tipos de carregamento, com 100 N cada: carregamento vertical (VL), carregamento vestibular (BL) e carregamento palatino (PL). A análise quantitativa das tensões foi realizada através do critério de Tensão Máxima Principal em cinco regiões de cada LCNC, nos seguintes pontos: ponto inicial, parede superior, centro da lesão, parede inferior e ponto final. Como resultado, as LCNCs restauradas com resina composta apresentaram distribuição de tensão semelhante a do modelo do dente hígido, independente da morfologia e do carregamento. O carregamento palatino foi responsável pelos maiores valores de acúmulo de tensão nas LCNCs. É possível conclui que Os diferentes tipos de morfologia das LCNCs apresentaram pequena influencia no padrão de distribuição de tensão. Os fatores de maior influência no comportamento biomecânico de pré-molares foram o tipo de carregamento e a presença da restauração.

Influence of dehydration on strain pattern of human and bovine teeth: in vitro study / Influência da desidratação no padrão de deformação de dentes humanos e bovinos: estudo in vitro

The aim of this study was to measure the effect of the elapsed time on micro-strain of dental structure by strain gauge test of human and bovine teeth. Ten standardized bovine incisors and ten standardized human premolars were obtained. To measure the strain it was fixed one strain gauge on the buccal of each sample and it was also performed a compression test on each of dehydration times: T0: immediately after removal from moisture; T5: after dehydration in room temperature (23 ± 1oC) for 5 minutes; T15: dehydration for 15 minutes; T45: dehydration for 45 minutes; T120: dehydration for 120 minutes; T24: dehydration for 24 hours; T24Re: dehydration for 24 hours and rehydration for 24 hours in distilled water. The results were statistically analyzed by using one-way ANOVA and Tukey’s test (p < 0.05). Mean and standard deviation values in micro-Strain (μS) of human teeth were: T0: 56.7 ± 28.5 a; T5: 56.9 ± 43.7 a; T15: 40.2 ± 29.7 ab; T45: 41.2 ± 22.1 ab; T120: 32.2 ± 22.5 ab; T24: 22.6 ± 21.7 b; T24Re: 38.5 ± 12.9 ab, and bovine teeth were: T0: 47.5 ± 15.6 a; T5: 39.2 ± 12.5ab; T15: 34.2 ± 11.5 abc; T45: 29.0 ± 7.9 bc; T120: 25.3 ± 10.5 bc; T24: 22.6 ± 10.2 bc; T24Re: 29.9 ± 13.2 bc. The μS values were decreased with increasing of the dehydration time for both teeth groups. It can be concluded that dehydration caused strain decreasing being necessary to keep the samples hydrated during strain gauge tests.

O objetivo deste estudo foi medir o efeito do tempo decorrido em microdeformação da estrutura dental por teste de extensometria de dentes humanos e bovinos. Obtiveram-se dez incisivos bovinos padronizados e dez pré-molares humanos padronizados. Para medir a deformação foram fixados extensômetros sobre a face vestibular de cada amostra, e também foi realizado um teste de compressão em cada um dos tempos de desidratação: T0: imediatamente após a remoção da umidade; T5: após desidratação em temperatura ambiente (23 ± 1°C) por 5 minutos; T15: desidratação por 15 minutos; T45: desidratação durante 45 minutos; T120: desidratação por 120 minutos; T24: desidratação por 24 horas; T24Re: desidratação por 24 horas e re-hidratação durante 24 horas em água destilada. Os resultados foram analisados estatisticamente utilizando o one-way ANOVA e teste de Tukey (p < 0,05). Os valores da média e desvio-padrão em microdeformação (μS) de dentes humanos foram: T0: 56,7 ± 28,5 a; T5: 56,9 ± 43,7 a; T15: 40,2 ± 29,7 ab; T45: 41,2 ± 22,1 ab; T120: 32,2 ± 22,5 ab; T24: 22,6 ± 21,7 b; T24Re: 38,5 ± 12,9 ab e dentes bovinos foram: T0: 47,5 ± 15,6 a; T5: 39,2 ± 12,5 ab; T15: 34,2 ± 11,5 abc; T45: 29,0 ± 7,9 bc; T120: 25,3 ± 10,5 bc; T24: 22,6 ± 10,2 bc; T24Re: 29,9 ± 13,2 bc. Os valores μS foram reduzidos com o aumento do tempo de desidratação para ambos os grupos de dentes. Pôde-se concluir que a desidratação causada promoveu maior rigidez da estrutura, sendo necessário manter as amostras hidratadas durante testes laboratoriais.