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.

Evaluation of the condylar position in younger and older adults with or without temporomandibular symptoms by using cone beam computed tomography.

STATEMENT OF PROBLEM: Recent studies in young adults have questioned the influence of discrepancies between central and maximal intercuspal positions in temporomandibular disorders (TMDs). However, whether this finding was because this type of etiologic agent requires time for the development of changes in the condylar position is unclear. PURPOSE: The purpose of this clinical study was to use cone beam computed tomography (CBCT) to evaluate the presence or absence of discrepancies between the centric relation (CR) and maximum intercuspation (MI) in younger and older adults in populations with or without TMDs. MATERIAL AND METHODS: The sample was composed of 80 volunteers, 40 younger individuals aged 18 to 25 years (27 women and 13 men), half with and half without TMD symptoms, and 40 older participants aged 35 to 50 years (30 women and 10 men), half with and half without TMD symptoms. The TMD symptoms were diagnosed by using the diagnostic (standard) criteria for TMD research (RDC/TMD). Two CBCT scans were performed on each participant, one in MI and another in CR. Measurements of the joint space were performed in coronal and sagittal cuts of the temporomandibular joints, and the collected data were statistically analyzed by using the Mann-Whitney U test (α=.05). RESULTS: No significant differences were found when the CR and MI positions and the presence or absence of TMD symptoms were compared in the younger and older groups. However, when the younger and older groups were compared, significant differences were found in all measures used in this study. CONCLUSIONS: The condyle and mandibular fossa do not seem to be influenced by the CR or MI positions or by the presence or absence of TMD symptoms, but age seems to lead to a quantitative increase in the relationship between these structures.

Changes in mandibular and articular dynamics associated with surgical versus nonsurgical treatment of mandibular condylar fractures: a systematic review with meta-analysis.

OBJECTIVE: The aim of this study was to evaluate the mandibular and articular dynamics and the presence of complications associated with surgical or nonsurgical treatments of condylar fractures. STUDY DESIGN: Clinical trials that compared open reduction internal fixation and maxillomandibular fixation in patients with condylar fractures were included. We performed an electronic search of PubMed, Scopus, Cochrane Library, Web of Science, and LILACS (Latin American and Caribbean Health Sciences) databases starting from February 2017 and updated in January 2019 and found 467 articles. We evaluated methodologic quality by using the criteria from Cochrane's Collaboration Tool. RESULTS: After independent screening of abstracts, we assessed the full texts of 88 articles; 9 studies were included for qualitative synthesis; but only 8 were included for the meta-analysis. Four studies were considered to have high risk of bias, and 5 were considered to have low risk. The risk ratio (RR = 0.20; 95% confidence interval [CI] 0.13-0.32) was observed for complications. The quality of evidence, using GRADE software, was considered low for maximum mouth opening and protrusive movement and moderate for lateral excursion movement and complications. CONCLUSIONS: This review suggested that open reduction internal fixation and maxillomandibular fixation are effective. However, surgical treatment presented higher objective parameters. Nonsurgical treatment presented a high index of complications, such as malocclusion, pain and deviation.

Influência do desequilíbrio oclusal na origem de lesão cervical não cariosa e recessão gengival: análise por elementos finitos / Influence of occlusal instability on the origin of non-carious cervical lesion and gingival recession: finite element analysis

Objetivo: avaliar o comportamento biomecânico de pré- -molar superior com presença de Lesões Cervicais Não Cariosas (LCNC) e submetido a três carregamentos oclusais distintos pelo método de elementos finitos tridimensional (3D). Material e método: nove modelos tridimensionais elásticos foram gerados, com propriedades ortotrópicas e isotrópicas: Hígido (H); LCNC não restaurada (LCNC) e LCNC restaurada com resina composta (RC); sendo todos estes modelos submetidos a três carregamentos: Axial (A), Oblíquo vestibular (V) e Oblíquo palatino (P). Os carregamentos tiveram intensidade de 150 N e a restrição de deslocamento foi realizada na base e lateral dos ossos cortical e medular. Os resultados foram gerados em tensão máxima e mínima principal. Resultados: O carregamento axial apresentou padrões de tensão mais favoráveis, independente da característica da região cervical. O carregamento palatino mostrou maior acúmulo de tensão de tração na região cervical vestibular e o carregamento vestibular resultou em maior tensão de compressão na tábua óssea vestibular. A presença de LCNC foi fator intensificador para o aumento da concentração de tensão na região cervical. A simulação da restauração com resina composta promoveu um comportamento biomecânico simular ao do hígido. Conclusões: que o carregamento palatino pode estar mais associado com a presença de LCNCs e o vestibular com a presença de recessão gengival. O ajuste oclusal e a restauração da LCNC são indicados para tornar o padrão de tensão mais favorável para o remanescente dentário.

Objective: to evaluate the biomechanical behavior of maxillary premolar with the presence of NCCL and submitted to three distinct occlusal loads, using the three-dimensional (3D) finite element analysis. Methods: nine three-dimensional elastic models were generated, with orthotropic and isotropic properties: Sound (H); Unrestored NCCL (NCCL) and NCCL restored with composite resin (RC); All models were submitted to three loads: Axial (A), Buccal (V) and Palataline (P). The loads intensity was 150 N and the displacement restriction was performed at the base and lateral of the cortical and medullary bones. The results were generated at maximum and minimum principal stress. Results: the axial loading presented more favorable stress pattern, independent of the characteristic of the cervical region. The palataline loading showed a greater concentration of tensile stress in the buccal cervical region and the buccal loading resulted in a higher compression stress in the buccal bone. The presence of NCCL was a relevant factor for increase concentration of stress in the cervical region. The simulation of the restoration with composite resin promoted a biomechanical behavior similar to that of the sound tooth. Conclusion that the palataline loading may be more associated with the presence of NCCLs and the vestibular with the presence of gingival recession. The occlusal adjustment and the restoration of NCCLs are indicated to produce the stress pattern more favorable for the dental remaining.

Effect of Occlusal Splints on the Stress Distribution on the Temporomandibular Joint Disc

Abstract Conservative approach, including occlusal splint therapy, is the first option to treat temporomandibular disorders (TMD), because of its reversibility. The present study analyzed the effect of the articular disc position and occlusal splints use on the stress distribution on this disc. A two-dimensional (2D) finite element (FE) model of the temporomandibular joint with the articular disc at its physiologic position was constructed based on cone-beam computed tomography. Three other FE models were created changing the disc position, according to occlusal splint use and anterior disc displacement condition. Structural stress distribution analysis was performed using Marc-Mentat package. The equivalent von Mises stress was used to compare the study factor. Higher stress concentration was observed on the intermediate to anterior zone of the disc, with maximum values over 2MPa. No relevant difference was verified on the stress distribution and magnitude comparing disc positions and occlusal splint use. However, there was stress reduction arising from the use of the occlusal splints in cases of anterior disc displacement. In conclusion, based on the generated FE models and established boundary conditions, the stress increased at the intermediate zone of the TMJ disc during physiological mandible closure. The stress magnitude was similar in all tested situations

Resumo Abordagens conservadoras, incluindo o uso de placas oclusais, são as primeiras opções de tratamento para disfunção temporomandibular (DTM), devido à sua reversibilidade. O presente estudo analisou o efeito da posição do disco articular e do uso de placa oclusal na distribuição de tensões no disco. Um modelo bidimensional (2D) de articulação temporomandibular (ATM) em posição fisiológica, foi desenvolvido para análise pelo método de elementos finitos, baseado em imagens de tomografia computadorizada do tipo cone-beam. Três outros modelos foram criados alterando a posição do disco de acordo com o uso de placa oclusal e condição de deslocamento anterior do disco. Uma análise estrutural da distribuição de tensões foi realizada no software Marc-Mentat, e equivalente Von Mises foi usado para comparar os fatores em estudo. Maior concentração de tensão foi observada na zona intermediária para a zona anterior do disco, atingindo valores máximos acima de 2 MPa. Nenhuma diferença relevante foi verificada na localização e magnitude das tensões quando comparadas as posições do disco e uso de placa oclusal. No entanto, houve pequena redução das tensões decorrente do uso de placa oclusal em caso de deslocamento anterior do disco. Conclui-se que mediante os modelos criados e condições de contorno estabelecidas, as tensões na zona intermediária do disco aumentam durante o fechamento mandibular fisiológico. A magnitude das tensões foi semelhante em todas as situações testadas

Effect of Occlusal Splints on the Stress Distribution on the Temporomandibular Joint Disc.

Conservative approach, including occlusal splint therapy, is the first option to treat temporomandibular disorders (TMD), because of its reversibility. The present study analyzed the effect of the articular disc position and occlusal splints use on the stress distribution on this disc. A two-dimensional (2D) finite element (FE) model of the temporomandibular joint with the articular disc at its physiologic position was constructed based on cone-beam computed tomography. Three other FE models were created changing the disc position, according to occlusal splint use and anterior disc displacement condition. Structural stress distribution analysis was performed using Marc-Mentat package. The equivalent von Mises stress was used to compare the study factor. Higher stress concentration was observed on the intermediate to anterior zone of the disc, with maximum values over 2MPa. No relevant difference was verified on the stress distribution and magnitude comparing disc positions and occlusal splint use. However, there was stress reduction arising from the use of the occlusal splints in cases of anterior disc displacement. In conclusion, based on the generated FE models and established boundary conditions, the stress increased at the intermediate zone of the TMJ disc during physiological mandible closure. The stress magnitude was similar in all tested situations.

Influence of Connection Types and Implant Number on the Biomechanical Behavior of Mandibular Full-Arch Rehabilitation.

PURPOSE: To evaluate the influence of different implant numbers and connection types on the biomechanical behavior of mandibular full-arch implant-supported rehabilitation. MATERIALS AND METHODS: Computed tomography-based finite element models comprising a totally edentulous mandible and 3.8 × 13-mmdiameter implants, abutments, abutment screws, bar retaining screw, and bar were constructed. Different implant numbers (three, four, and five implants) and loading conditions (symmetrical/balanced, unilateral, and posterior with diverse loading magnitudes) were simulated for both external hex and Morse-taper connections. The peak equivalent strain (EQV strain) in the bone and the peak of von Mises stress (EQV stress) in the abutment screw and bar retaining screw were evaluated. RESULTS: Lower strain values were observed for a symmetrical loading distribution. Considering the same loading conditions, significantly higher bone strain levels were observed for external hex, compared with the Morse-taper connection. The number of implants had no significant influence on strain levels in bone, irrespective of the connection types. Compared with the external hex connection, the Morse-taper connection type presented significantly lower EQV stress values in abutment screws, but significantly higher stress in the bar retaining screw. Increasing the number of implants significantly reduced the EQV stress in the abutment screw and bar retaining screw. CONCLUSION: The Morse-taper connection type significantly decreased the strain levels in peri-implant bone, while increasing the stress in bar retaining screws. A smaller number of implants in an inferior full-arch rehabilitation slightly increased the stress in the abutment and bar retaining screws. Balanced adjustments of the loading improve the biomechanics of a mandibular full-arch rehabilitation.

Cone-beam computed tomography evaluation of dentoskeletal effects produced by the bonded expander and hyrax: a pilot study / Avaliação por tomografia computadorizada de feixe cônico dos efeitos dentoesqueléticos produzidos pelo expansor colado e hyrax: um estudo piloto

The dentoskeletal effects produced by the bonded expander, principally the vertical ones, are controversial in the literature when compared with the effects produced by the hyrax, and have also been scarcely studied by means of cone-beam computed tomography (CBCT). This study aimed to evaluate the horizontal and vertical dentoskeletal effects produced by the bonded expander and by the hyrax using CBCT. The study sample consisted of ten patients, divided equally into two groups according to facial and cephalometric features: group 1, vertical facial growth pattern (two males, three females; mean age, 7.7 years) and group 2, normal facial growth pattern (three males, two females; mean age, 8.3 years), treated by bonded expander and hyrax, respectively. The patients were subjected to a CBCT scan before expansion and another scan four months after the end of the activations, when the expander was removed. Within each group and between the groups the horizontal and vertical effects were assessed using Student's t-test. The sample size was predetermined, and 5 patients were needed in each group to detect the differences at P < 0.05 with 90% power. Among the horizontal changes assessed, the nasal floor width (P = 0.03) and the greater internal width in the posterior region (P = 0.00) showed a statistically significant increase only for group 1, and the mandibular molar verticality showed a statistically significant increase only for group 2. The vertical changes showed no statistical differences within groups (P > 0.05). Comparing the two groups there were no statistical differences for any assessed change (P > 0.05). Considering there were no differences of the effects between the appliances, the bonded expander produced no greater vertical control compared to the hyrax. Nevertheless, further study is recommended in a larger sample size using CBCT.

Os efeitos dentoesqueléticos produzidos pelo expansor colado, principalmente os efeitos verticais, são controversos na literatura quando comparados aos efeitos produzidos pelo expansor hyrax, e pouco estudado por meio de tomografia computadorizada de feixe cônico (TCFC). O objetivo deste estudo foi avaliar os efeitos dentoesqueléticos horizontais e verticais produzidos pelo expansor colado e pelo hyrax, utilizando-se TCFC. A amostra do estudo consistiu de cinco pacientes, divididos igualmente em dois grupos de acordo com as características faciais e cefalométricas: grupo 1, padrão de crescimento facial vertical (dois do sexo masculino, três do sexo feminino, idade média 7,7 anos), e grupo 2, padrão de crescimento facial normal (três do sexo masculino, duas do sexo feminino, idade média 8,3 anos) tratados com expasor colado e hyrax, respectivamente. Os pacientes foram submetidos à escaneamento de TCFC antes da expansão e após quatro meses da última ativação, quando o expansor foi removido. Nas comparações intra e inter-grupos, os efeitos horizontais e verticais foram avaliados por meio do teste t de Student. O tamanho da amostra foi pré-determinado, e cinco pacientes foram necessários em cada grupo para detectar diferenças para P < 0,05 e com 90% de poder. Dentre as alterações horizontais avaliadas, a largura do assoalho nasal (P = 0,03) e a maior largura nasal interna na região posterior (P = 0,00) mostraram aumento estatisticamente significante apenas para o grupo 1, e a verticalização do molar inferior mostrou aumento estatisticamente significante apenas no grupo 2 (P = 0,01). As alterações verticais avaliadas não demonstraram diferença estatística intra-grupos. Na comparação inter-grupos não foi encontrada diferença estatística em nenhum parâmetro avaliado (P > 0,05). Dado que não houve diferença na comparação inter-grupos, o expansor colado não produziu maior controle vertical em relação ao hyrax. No entanto, é recomendada a realização de mais estudos com maior amostra utilizando-se TCFC.

Periodontal and Restorative Treatment of Gingival Recession Associated with Non-Carious Cervical Lesions: Case Study.

The association between the presence of gingival recession and non-carious cervical lesions is a common finding in dentistry. These diseases have multifactorial etiology and the treatment should be multidisciplinary. Although traditionally the majority of professionals treat non-carious cervical lesions only with conventional restorative procedures, in most cases a combination of periodontal and restorative treatments provides the best functional and esthetic results. Thus, the objective of this case report was to present a new option for treatment, which consists of a subepithelial connective tissue graft associated with a coronally advanced flap placed on dentin and non-carious cervical lesions restored with lithium disilicate partial veneers. A patient complaining about the esthetic aspects of her teeth and cervical dentin hypersensitivity was submitted to occlusal adjustments and daily diet analysis in order to manage etiologic factors. Experienced operators then performed restorative and surgical treatments. Periodontal clinical attachment level (probing depth + gingival margin), bleeding on probing, plaque index, and the integrity of the restorations were observed. During the monitoring period, the treatment was effective, with good functional and esthetic results. The hypersensitivity disappeared, and neither inflammatory characteristics in gingival tissue nor failures in restorations were noted. It might be concluded that treatment with a combination of techniques can be effective and predictable for patients with gingival recession and non-carious cervical lesions that may or may not require restorative procedures under controlled conditions.

Evaluation of a dentoalveolar model for testing mouthguards: stress and strain analyses.

BACKGROUND/AIM: Custom-fitted mouthguards are devices used to decrease the likelihood of dental trauma. The aim of this study was to develop an experimental bovine dentoalveolar model with periodontal ligament to evaluate mouthguard shock absorption, and impact strain and stress behavior. METHODS: A pendulum impact device was developed to perform the impact tests with two different impact materials (steel ball and baseball). Five bovine jaws were selected with standard age and dimensions. Six-mm mouthguards were made for the impact tests. The jaws were fixed in a pendulum device and impacts were performed from 90, 60, and 45° angles, with and without mouthguard. Strain gauges were attached at the palatal surface of the impacted tooth. The strain and shock absorption of the mouthguards was calculated and data were analyzed with 3-way anova and Tukey's test (α = 0.05). Two-dimensional finite element models were created based on the cross-section of the bovine dentoalveolar model used in the experiment. A nonlinear dynamic impact analysis was performed to evaluate the strain and stress distributions. RESULTS: Without mouthguards, the increase in impact angulation significantly increased strains and stresses. Mouthguards reduced strain and stress values. CONCLUSIONS: Impact velocity, impact object (steel ball or baseball), and mouthguard presence affected the impact stresses and strains in a bovine dentoalveolar model. Experimental strain measurements and finite element models predicted similar behavior; therefore, both methodologies are suitable for evaluating the biomechanical performance of mouthguards.

Temporomandibular disorder and anxiety, quality of sleep, and quality of life in nursing professionals.

To evaluate the association between temporomandibular disorder (TMD) and anxiety, quality of sleep, and quality of life in nursing professionals at the Hospital de Clínicas de Uberlândia of the Universidade Federal de Uberlandia--HCU-UFU (Medical University Hospital of the Federal University of Uberlândia), four questionnaires were given to nursing professionals. The questionnaires were completed by 160 of these professionals. The Fonseca's questionnaire was used to evaluate the presence and severity of TMD, the IDATE was used to evaluate anxiety, the SAQ was used to evaluate quality of sleep, and the SF-36 was used to evaluate quality of life. Forty-one nurses (25.6%) reported having no TMD (Fonseca's questionnaire score ≤ 15), 66 (41.3%) had mild TMD (Fonseca's questionnaire score 20-40), 39 (24.4%) had moderate TMD (Fonseca's questionnaire score 45-65), and 14 (8.8%) had severe TMD (Fonseca's questionnaire score ≥ 70). According to Fonseca's questionnaire, the presence of TMD was associated with trait anxiety, but the TMD severity was associated with state anxiety classification (mild, moderate, severe). The SAQ score differed significantly from Fonseca classification. The Fonseca's questionnaire score correlated negatively with the score of each dimension of the SF-36 (r = -0.419 to -0.183). We conclude that TMD is common among nursing professionals; its presence was associated with trait anxiety, and its severity was associated with state anxiety. Hence, the presence of TMD may reduce quality of sleep and quality of life.

Cone-beam tomography assessment of the condylar position in asymptomatic and symptomatic young individuals.

STATEMENT OF PROBLEM: Studies of the condyle-mandibular fossa relationship are common, although the role of this relationship in the development of a temporomandibular disorder remains controversial. PURPOSE: The purpose of this study was to quantitatively evaluate the condyle-mandibular fossa relationship in young individuals with intact dentitions and compare it to that between individuals with and without symptoms of temporomandibular disorder. MATERIAL AND METHODS: Volunteers were classified as asymptomatic (n=20) or symptomatic (n=20) according to research diagnostic criteria for temporomandibular disorders. Each participant underwent 2 cone beam-computed tomography scans of the middle and lower third of the face: 1 scan of the maximum intercuspation position and 1 of the centric relationship position. The distance between the condyle and mandibular fossa was measured on frontal and lateral images of the temporomandibular joint. The condylar position was compared across groups (asymptomatic, symptomatic) by using the Mann-Whitney U test (α=.05). Within each group, the condylar position was compared across maximum intercuspation and centric relationship positions by using the Mann-Whitney U test (α=.05). RESULTS: No statistically significant differences were found in condylar positions between centric relationships and maximum intercuspation in either asymptomatic or symptomatic young adults, and no significant differences were found between asymptomatic and symptomatic young adults. CONCLUSIONS: The condyle-mandibular fossa relationships of these young adults were similar in the centric relationships and maximum intercuspation positions when evaluated by computed tomography. The presence or absence of temporomandibular disorder was not correlated with the condyle position in the temporomandibular joint.

Retrieval technique for full-arch implant-supported fixed prosthesis: a clinical report.

In the event of the loss of an implant and to take advantage of the preexisting structures, a rescue procedure that allows continuous use of the original fixed restoration during the restoration of the tripod support at the implant level can be used. When nonphysiological occlusion forces are avoided, the success rate of this rescue procedure is very similar to any other rehabilitation made following a conventional protocol. Furthermore, the fact that the patient has already adapted to the prosthesis position and its vertical dimension results in easier functional adaptation in the postoperative period and, consequently, greater comfort.

Temporomandibular disorder and anxiety, quality of sleep, and quality of life in nursing professionals

To evaluate the association between temporomandibular disorder (TMD) and anxiety, quality of sleep, and quality of life in nursing professionals at theHospital de Clínicas de Uberlândiaof theUniversidade Federal de Uberlândia – HCU-UFU (Medical University Hospital of the Federal University of Uberlândia), four questionnaires were given to nursing professionals. The questionnaires were completed by 160 of these professionals. The Fonseca’s questionnaire was used to evaluate the presence and severity of TMD, the IDATE was used to evaluate anxiety, the SAQ was used to evaluate quality of sleep, and the SF-36 was used to evaluate quality of life. Forty-one nurses (25.6%) reported having no TMD (Fonseca’s questionnaire score ≤ 15), 66 (41.3%) had mild TMD (Fonseca’s questionnaire score 20–40), 39 (24.4%) had moderate TMD (Fonseca’s questionnaire score 45–65), and 14 (8.8%) had severe TMD (Fonseca’s questionnaire score ≥ 70). According to Fonseca’s questionnaire, the presence of TMD was associated with trait anxiety, but the TMD severity was associated with state anxiety classification (mild, moderate, severe). The SAQ score differed significantly from Fonseca classification. The Fonseca’s questionnaire score correlated negatively with the score of each dimension of the SF-36 (r = –0.419 to –0.183). We conclude that TMD is common among nursing professionals; its presence was associated with trait anxiety, and its severity was associated with state anxiety. Hence, the presence of TMD may reduce quality of sleep and quality of life.

Correlation between temporomandibular disorders, occlusal factors and oral parafunction in undergraduate students

Aim: To investigate the prevalence of temporomandibular disorders (TMD) in undergraduate students and to correlate its prevalence with occlusal factors and parafunctional habits. Methods: 201 undergraduate students were evaluated. The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) was filled out at the beginning of the study, followed by occlusal analysis based on morphological and functional alterations. The identification of tooth grinding and clenching was carried out by self-reports. Statistical analysis was based on chi-square and multivariate logistic regression analyses. p-value for all statistical analysis was set at 5%. Results: According to RDC/TMD, 18.4% of subjects experienced myofascial pain (G-MPD), and 12.4% had joint disorder with disc displacement (G-DD). Tooth clenching was statistically associated with TMD (p=0.000). In the occlusal factors, overjet showed statistically significant correlation only with myofascial pain. No association between functional alteration and TMD was found. No statistically significant correlation was found between G-DD and occlusal alterations or parafunctional habits. Conclusions: Overjet and tooth clenching were correlated with G-MPD. Occlusal alterations or parafunctional habits did not show correlation with G-DD.

Potential of coconut water and soy milk for use as storage media to preserve the viability of periodontal ligament cells: an in vitro study.

AIM: There is no consensus regarding the ability of coconut water and soy milk to maintain long-term cell viability. This study investigated the ability of pH-adjusted coconut water and soy milk to maintain the viability of periodontal ligament cells over a short and a longer period and compared these abilities with those of other solutions. METHODS: Dog premolar teeth were extracted, dried for 30 min, and stored in the following media for 50 min or 24 h: long shelf-life whole milk (SWM), long shelf-life skim milk (SSM), Hank's Balanced Salt Solution (HBSS), soy milk (SM), and pH-adjusted coconut water (CW). The positive and two negative control groups corresponded to 0-min, 30-min (short-term), and 24-h (long-term) dry times, respectively. Cell viability was analyzed by trypan blue exclusion. Data were statistically analyzed using the Kruskal-Wallis test with post-analysis using the Dunn method. RESULTS: In the short-term experiment, the SSM resulted in significantly lower cell viability than SM and CW. At 24 h, SM and CW resulted in higher viability than HBSS and SSM and in comparable performance with the positive control group. Cell viability decreased over time, except in SM and CW. CONCLUSIONS: Soy milk and pH-adjusted coconut water showed promising results as storage solutions for avulsed teeth, preserving the viability for up to 24 h.

Identification of occlusal prematurity by clinical examination and cone-beam computed tomography.

The aim of this study was to evaluate the ability to identify occlusal prematurity by images from paraxial slices of cone-beam computed tomography (CBCT). For such purpose, a pilot study was performed in which 16 asymptomatic young patients were subjected to a clinical examination, including a careful occlusal analysis and then individual deprogrammer devices ("Lucia's JIG") were fabricated. Premature contacts were clinically identified in centric relation (CR) for each patient by jaw manipulation and interocclusal marking with articulating paper (Accufilm). Subsequently, these devices were adjusted in CR and used during the tomographic exams in such a way that CBCT in CR could be obtained. After routine processing, the images were analyzed in order to identify occlusal prematurity on the displayed images by 30 professionals divided according to areas of activity (occlusion specialist, general practitioner and radiologist; n=10 per area) and time of professional experience (less than 5, between 5 and 10, and over 10 years). By comparing the premature contacts identified in the clinical analysis and CBCT images, an agreement index between these two variables was calculated. Data were analyzed statistically by ANOVA and Scott-Knott test (α=0.05). The results showed that the identification of occlusal prematurity by paraxial CBCT slices was proven to be a method of average reliability.

Identification of occlusal prematurity by clinical examination and cone-beam computed tomography

The aim of this study was to evaluate the ability to identify occlusal prematurity by images from paraxial slices of cone-beam computed tomography (CBCT). For such purpose, a pilot study was performed in which 16 asymptomatic young patients were subjected to a clinical examination, including a careful occlusal analysis and then individual deprogrammer devices (“Lucia's JIG”) were fabricated. Premature contacts were clinically identified in centric relation (CR) for each patient by jaw manipulation and interocclusal marking with articulating paper (Accufilm). Subsequently, these devices were adjusted in CR and used during the tomographic exams in such a way that CBCT in CR could be obtained. After routine processing, the images were analyzed in order to identify occlusal prematurity on the displayed images by 30 professionals divided according to areas of activity (occlusion specialist, general practitioner and radiologist; n=10 per area) and time of professional experience (less than 5, between 5 and 10, and over 10 years). By comparing the premature contacts identified in the clinical analysis and CBCT images, an agreement index between these two variables was calculated. Data were analyzed statistically by ANOVA and Scott-Knott test (α=0.05). The results showed that the identification of occlusal prematurity by paraxial CBCT slices was proven to be a method of average reliability.

O objetivo deste estudo foi avaliar a capacidade de identificação de prematuridades oclusais por meio de imagens obtidas de cortes paraxiais de tomografias computadorizadas de feixe cônico. Para este fim, realizou-se um estudo piloto em que 16 pacientes jovens assintomáticos foram submetidos ao exame clínico, incluindo análise oclusal criteriosa, e em seguida foram confeccionados dispositivos desprogramadores individuais (“JIG de Lucia”). Mediante manipulação mandibular e marcação interoclusal com papel carbono (Accufilm) identificou-se clinicamente o contato prematuro em relação cêntrica (RC) de cada paciente. Posteriormente estes dispositivos foram ajustados na posição de contato cêntrico e utilizados durante os exames tomográficos para que se pudessem obter imagens tomográficas na posição de relação cêntrica. Após o processamento das imagens, estas foram analisadas com o intuito de identificar prematuridades oclusais nas imagens visualizadas por 30 profissionais divididos de acordo com as áreas de atuação (Oclusão, Clínica Geral e Radiologia, n=10 para cada área) e tempo de exercício profissional (<5; entre 5 e 10; e >10 anos). Mediante comparação entre os contatos prematuros identificados na análise clínica oclusal e as imagens tomográficas apontadas pelos profissionais como áreas de contatos prematuros, foram calculados os índices de concordância entre essas duas variáveis. Os dados obtidos foram analisados estatisticamente pela Análise de Variância ANOVA e teste de Scott-Knott (α=0,05). Os resultados deste estudo demonstraram que a identificação de prematuridades oclusais por meio de cortes paraxiais de tomografias computadorizadas de feixe cônico mostrou-se como um método de confiabilidade média.

Influence of different load application devices on fracture resistance of restored premolars

This in vitro study analyzed the effect of different load application devices on fracture resistance and failure mode of maxillary premolars restored with composite resin. Sixty human maxillary premolars received standardized mesio-occluso-distal cavity preparations and were restored with composite resin. The specimens were randomly divided into 6 groups (n=10). Compressive loading was applied using 6 different metallic devices: S2: 2-mm sphere; S6: 6-mm sphere; C2: 2-mm cylinder; C6: 6-mm cylinder; WS: wedge shape device; and MAT: individualized metallic antagonist tooth. Data were analyzed statistically using one-way ANOVA and Tukey's test (α=0.05). The failure mode was recorded based on the 4 sequential levels. Statistical analysis revealed that WS presented significantly higher fracture resistance than S6 and C6. No significant difference was found among MAT, C2, S2 and S6. Sphere and cylinder with 6 mm were similar, with the lowest values of all groups. MAT presented the least number of catastrophic failures while C2, S2 and WS presented the highest. The type of load application device influences significantly the behavior of the teeth-restoration complex during mechanical fracture resistance test.

Este estudo avaliou o efeito de diferentes tipos de dispositivos de aplicação de carga na resistência à fratura de pré-molares superiores restaurados com resina composta. Sessenta pré-molares humanos receberam preparo mésio-ocluso-distal padronizado e as cavidades foram restauradas com resina composta. As amostras foram aleatoriamente divididas em 6 grupos (n=10). Carregamento de compressão foi realizado usando seis diferentes dispositivos metálicos de aplicação de carga: S2 e S6: esfera de 2 mm e 6 mm de diâmetro respectivamente; C2 e C6: cilindro de 2 mm e 6 mm de diâmetro respectivamente; WS: lâmina de faca e MAT: antagonista individualizado em metal. Os resultados foram submetidos à análise de variância e teste de Tukey (p<0,05). O modo de falha foi classificado em 4 níveis e estão apresentado em porcentagem. O dispositivo WS resultou em maior resistência a fratura de pré-molares que S6 e C6. Não houve diferença estatística entre os grupos MAT, C2, S2 e S6. Menor resistência foi verificada com o uso de S6 e C6. O dispositivo MAT resultou em menor número de falhas catastróficas enquanto nos grupos C2, S2 e WS essas falhas foram significativas. O tipo de dispositivo de aplicação de carga influenciou significativamente no comportamento do complexo dente-restauração durante o teste de resistência à fratura.