Relationship between presence of abfractions and premature contacts

ABSTRACT: Abfractions (AFs) are non-carious cervical lesions considered of multifactorial etiology by several authors. Objective: Relate the presence of premature contacts and AFs. Materials & Methods: The original number of students to be analyzed were 117, 36 of whom (equal amount of women and men) were finally chosen for presenting premature contacts. 19 of them presented abfractions. A survey was conducted with questions on issues like toothbrushing habits, diet and some gastric disorders; besides the participants had to take the Hamilton Anxiety Rating Scale. Then, stone models were obtained and mounted for further occlusal analysis with WCM ® semi-adjustable articulator searching the abfractions and their coincidence with premature contacts. Fisher's exact test (p<0,05) was used to associate AF with toothbrushing habits, diet, burning symptoms and gastroesophageal reflux. Chi-square test (p<0,05) was used to associate AFs and premature contacts. Student's t-distribution was used to associate AFs with anxiety. Results: There was a significant relationship between AFs presence and premature contacts (p=0,00). There was not a significant relationship between presence of AFs and toothbrushing habits and diet. There was not a significant relationship between presence of AFs and anxiety. Conclusions: AF presence do associate with premature contacts in the same affected tooth.

Resistencia adhesiva de postes de fibra a los diferentes tercios del conducto radicular / Adhesive resistance of fiber posts to different thirds of the root canal

En los últimos años resulta de elección la utilización de postes de fib ra en la rehabilitación de piezas endodónticamente tratadas. La adhesión entre poste, agente cementante y dentina radicular permitiría lograr una retención de la estructura dentro de las paredes del conducto. El objetivo de este estudio fue comparar la resistencia adhesiva en los tercios cervical, medio y apical, entre la dentina del conducto radicular y el cemento adhesivo utilizado en la cementación de postes de fibra. Se utilizaron 30 premolares inferiores uniradiculares humanos, recientemente extraídos, se realizaron los tratamientos endodónticos, se desobturaron y realizaron las preparaciones con la fresa conformadora número 3 para la cementación de postes White Post DC especial número 3 con cemento Paracore utilizando el protocolo adhesivo del mismo sistema. Las muestras fueron incluidas en acrílico cristal, cortadas en forma perpendicular al eje mayor de la pieza con una máquina de corte y por último se procedió a medir los valores de adhesión de los postes a la superficie interna de los conductos en los tres tercios con la prueba push-out mediante una máquina de ensayo universal. Los resultados arrojaron que las resistencias (media +- DE, MPa) en los tercios cervical, medio y apical, fueron 8,74 +- 3,12, 9,38 +- 2,29 y 11,11 +- 2,95, respectivamente. En el tercio apical se registró mayor resistencia. Considerando las limitaciones de esta investigación, se puede concluir que la cementación de postes de fibra con cementos resinosos, presenta mayores valores en el tercio apical y menores en el tercio cervical del conducto radicular con técnica de Push-out (AU)

TruNatomy: ¿un nuevo instrumento o un concepto diferente? / TruNatomy: a new instrument or a different concept?

La alta incidencia de fracturas dentarias producidas a distancia del tratamiento endodóntico ha llevado a desarrollar cambios en los procedimientos operatorios, con el objeto de conservar la mayor cantidad de estructura dentaria durante la terapia de conductos radiculares. En relación con esta idea, el sistema TruNatomy trabaja sobre el concepto de endodoncia mínimamente invasiva. Una zona altamente sensible a ser considerada es el área pericervical, delimitada 4 mm por encima y 4 mm por debajo de la cresta ósea. El objetivo del presente informe es analizar las propiedades y las características técnicas del sistema de instrumentación Tru- Natomy y los cambios conceptuales que su utilización implica (AU)

The high incidence of dental fractures in the long-term after endodontic treatment has led to analyzed how to change the endodontic procedures to preserve the dental structure during root canal therapy. The TruNatomy system was developed based on the concept of Minimally Invasive Endodontics. A highly sensitive zone to be considered is the pericervical area, restricted to 4 mm above and 4 mm below the bone crest. The objective of this report is to analyze the properties and technical characteristics of the TruNatomy instrumentation system and the changes in the concepts in the clinical treatment procedures as a result of its use (AU)

Six month follow-up of two bulk-fill composites in non-carious cervical lesions: double blind randomized clinical trial / Evaluación clínica a 6 meses de restauraciones cervicales en lesiones no cariosas con resinas compuestas bulk-fill: estudio aleatorio doble ciego

Objective: To assess the six-month clinical outcome of restorations of non-carious cervical lesions (NCCL) with two composite resins: Bulk-Fill and nanohybrid resin. Materials and methods: Fifty-one patients, with three NCCLs each, were randomly allocated into three restoration groups: Tetric-N-Ceram Bulk-Fill (TB); Filtek Bulk-Fill (FB); y Filtek Z350XT (Z350). Adhesive techniques and restorative procedures were performed according to the manufacturers' instructions for the different materials. A 4mm increment was applied in TB and FB, and increments of ≤2mm depth were applied in Z350. Restorations were assessed by two calibrated examiners at baseline and at six months according to the FDI World Dental Federation guidelines (1: excellent, 2: acceptable, 3: sufficient, 4: unsatisfactory, 5: unacceptable) in Marginal Staining (MS), Fracture-Retention (FR), Marginal Adaptation (MA), Postoperative Sensitivity (S) and Caries (C). Wilcoxon test was used for the comparison between baseline and 6 months, and Kruskal-Wallis for the comparison of the three groups at six months (95% significance). Results: Forty-six patients with a total of 138 restorations attended a check-up at six months and were evaluated with excellent clinical outcome. In MS, 91.2% for Z350 and 97.8% for FB and TB; in FR, 97.8% for Z350 and 100% for FB and TB; in MA, 95.6% for Z350, 97.8% for FB and 100% for TN; in S, 95.6% for all three groups; and 100% for C. No statistically significant differences were found between the three groups nor in the comparison between the baseline and 6 months (p>0.05) Conclusion: No significant differences are observed between the three groups of resins in the parameters of MS, MA, S, FR and C regarding clinical outcome at six months.

Objetivo: Evaluar el comportamiento clínico a 6 meses en restauraciones de lesiones cervicales no cariosas (LCNC) con dos resinas compuestas Bulk-Fill y una resina nanohíbrida. Materiales y métodos: En 51 pacientes se restauraron 3 LCNC distribuidas aleatoriamente en 3 grupos, TB: Tetric-N-Ceram Bulk-Fill, FB: Filtek Bulk-Fill y Z350: Filtek Z350XT. Las técnicas adhesivas y procedimientos restauradores fueron realizados según las instrucciones de los fabricantes para los diferentes materiales. En TB y FB se aplicó un incremento de 4mm y en Z350 se aplicó incrementos ≤2mm de profundidad. Dos operadores calibrados evaluaron las restauraciones al baseline y 6 meses mediante los criterios clínicos FDI (1: excelente, 2: aceptable, 3: suficiente, 4: insatisfactorio, 5: inaceptable) en Tinción Marginal (TM), Fractura-Retención (FR), Adaptación Marginal (AM), Sensibilidad Postoperatoria (S) y Caries (C). Se utilizó Wilcoxon para la comparación entre baseline ­ 6 meses y Kruskal-Wallis para la comparación de los 3 grupos a 6 meses (significancia de 95%). Resultados: A los 6 meses asistieron 46 pacientes con un total de 138 restauraciones siendo evaluados con comportamiento clínico excelente; en TM 91,2% para Z350 y 97,8% para FB y TB; en FR, Z350 presentó 97,8% y en FB y TB el 100%; en AM, 95,6% para Z350, 97,8% para FB y 100% para TN; en S presentó 95,6% para los tres grupos; en C se presentó el 100%. No hubo diferencias estadísticamente significativas entre los 3 grupos y en la comparación de baseline - 6 meses (p>0.05). Conclusión: No existen diferencias significativas en el comportamiento clínico a 6 meses entre los 3 grupos de resinas en los parámetros TM, AM, S, FR Y C.

Prevalence of impacted mandibular third molars and its association with distal caries in mandibular second molars using cone beam computed tomography / Prevalencia de terceros molares mandibulares impactados y su asociación con caries distales en segundos molares mandibulares mediante tomografía computarizada de haz cónico

This study evaluated the prevalence and eruption's pattern of impacted mandibular third molars (IMTM) and the influence of their eruption status on the distal caries of mandibular second molars (MSM) using cone-beam computed tomography (CBCT). Material and methods: CBCT images taken for different purposes in private dental practices were analyzed retrospectively. Radiographic assessment included: prevalence of IMTM, degree of angulation, level of impaction and type of IMTM. Furthermore, the distance between the cement-enamel junctions (CEJ) of second and third molars and the occurrence of caries lesion on the distal surface of MSM was also evaluated. Data were analyzed by chi square test and logistic regression was used to find the association between distal caries of MSM and eruption status of IMTM. Results: Three hundred and eight CBCTs were screened, the prevalence of IMTM was 36.88% and their angulation degree were mostly less than 90º (mesioangular). Amongst those with impaction, 58 subjects (43%) had distal caries on MSM, 29.6% in females and 30.4% in the age group 19-27 years. Caries on the distal side of MSM were significantly associated with age, level and type of impaction, angulation degree and CEJ distances (p<0.05). Conclusions: The prevalence of IMTM is high (36.88%) and there are significant relationships between angulation degree, level and type of impaction, and CEJ distances with caries on the distal side of MSM.

Introducción: Este estudio evaluó la prevalencia y el patrón de erupción de terceros molares mandibulares impactados (TMMI), y la influencia de su estado de erupción en la caries distal de los segundos molares mandibulares (SMM) mediante tomografía computarizada de haz cónico (TCHC). Material y métodos: se analizaron retrospectivamente las imágenes de TCHC tomadas para diferentes fines en prácticas dentales privadas. La evaluación radiográfica incluyó: prevalencia de TMMI, grado de angulación, nivel de impacto y tipo de TMMI. Además, también se evaluó la distancia entre la unión amelocementaria (UAC) de los segundos y terceros molares y la aparición de lesión de caries en la superficie distal de SMM. Los datos se analizaron mediante la prueba de chi cuadrado y se usó la regresión logística para evaluar asociaciones entre la caries distal de SMM y el estado de erupción de TMMI. Resultados: Se examinaron 308 TCHC, la prevalencia de TMMI fue de 36.88% y su grado de angulación fue mayoritariamente menor a 90º (mesioangular). Entre aquellos con impacto, 58 sujetos (43%) tenían caries distales en los SMM, 29.6% eran mujeres y 30.4% pertenecieron al grupo de edad de 19-27 años. Las caries en el lado distal de MSM se asociaron significativamente con la edad, el nivel y el tipo de impactación, el grado de angulación y las distancias UAC (p<0.05). Conclusiones: la prevalencia de TMMI es alta (36.88%) y existen relaciones significativas entre el grado de angulación, el nivel y el tipo de impacto, y las distancias UAC con presencia de caries en el lado distal de los SMM.

Lesões cervicais não cariosas: uma abordagem no controle da dor e tratamento

Objetivo: o objetivo deste trabalho é relatar um caso clínico de hipersensibilidade severa associada a múltiplas lesões cervicais não cariosas, entender o mecanismo de ação e a eficácia dos agentes dessensibilizantes. Relato de caso: paciente do gênero masculino, 38 anos de idade, compareceu à clínica da Faculdade Morgana Potrich com um quadro de hipersensibilidade em vários elementos, bem como, a presença de lesão cervical não cariosa em alguns desses elementos. Durante a anamnese o paciente relatou o hábito de escovar os dentes várias vezes ao dia logo após se alimentar, exercendo muita força durante o ato, relatou também fazer consumo diário de cerveja que possui um pH ácido. Ao realizar análise da oclusão notou-se um desequilíbrio oclusal e contato prematuro nos dentes 24 e 34. O tratamento de escolha para esse caso foi o ajuste oclusal seguido do uso de dessensibilizantes e restaurações em resina composta nos dentes que havia a presença de lesões cervicais não cariosas com perda de estrutura dentária. Considerações finais: após esse tratamento, realizado em várias sessões, foi possível devolver ao paciente a função e eliminar a dor provocada pela hipersensibilidade, proporcionando uma melhor qualidade de vida para esse paciente.

Objective: This study aims to report a clinical case of severe hypersensitivity associated with multiple non-carious cervical lesions and to understand the mechanism of action and the efficacy of desensitizing agents. Case report: A 38-year-old male patient attended the clinic at Faculdade Morgana Potrich with the hypersensitivity of several elements and the presence of non-carious cervical lesion in some of these elements. During anamnesis, the patient reported the habit of toothbrushing several times a day soon after eating, exerting a lot of force in such activity; he also reported the daily consumption of beer, which has an acidic pH. The occlusal analysis showed occlusal disorder and premature contact in teeth 24 and 34. The treatment of choice for this case was the occlusal adjustment followed by the use of desensitizers and composite resin restorations on the teeth with non-carious cervical lesions with loss of dental structure. Final considerations: After this treatment, which was performed in several sessions, it was possible to return function to the patient and eliminate the pain caused by hypersensitivity, providing a better quality of life for this patient.(au)

Comparison of the clinical effect of the adhesive strategies of universal adhesives in the treatment of non-carious cervical lesions: systematic review and meta-analysis

Objective: to compare, through a systematic review and a meta-analysis, the clinical effect of the adhesive strategies of universal adhesives (UA) in the treatment of non-carious cervical lesions (NCCLs). material and method: a search of the literature was carried out up to january 2018, in the biomedical databases: Pubmed, Embase, Scielo, Science Direct, SIGLE, LILACS, BBO, Google Scholar and the Central Register of Cochrane Clinical Trials. the selection criteria of the studies were as: randomized clinical trials, with a maximum age of 5 years and which report the clinical effects (marginal adaptation, discoloration or marginal staining, presence of secondary caries, postoperative sensitivity, retention and fractures) of the UA in the treatment of NCCLs. the risk of study bias was analyzed through the Cochrane Handbook of systematic reviews of interventions. results: the search strategy resulted in eight articles that reported no difference in marginal adaptation, discoloration or marginal staining, presence of secondary caries and postoperative sensitivity among the adhesive strategies of the UA; however they reported a difference between the retention and the presence of fractures, with the conventional adhesive strategy resulting in a better clinical effect. conclusion: the reviewed literature suggests that the conventional adhesive strategy of UAs results in greater retention and absence of fractures in the treatment of NCCLs.

Tomographic late evaluation of xenogeneic bone grafts in sockets of impacted third molars

Abstract It is necessary to preserve height and thickness of the alveolar bone to facilitate rehabilitation with osteointegratable implants or simply to maintain bone integrity after extraction. Biomaterials associated with resorbable or non-resorbable membranes, when placed in the region of the socket, may contribute to avoid this unwanted reabsorption. Objective The objective of this study was to evaluate the distance of the crest of alveolar ridge to the cementoenamel junction (CEJ) of the lower second molars and the bone density of the third molar socket filled with Gen-Tech®, 5 years after an exodontia using cone beam computed tomography (CBCT) to visualize the central region of the sockets, without overlapping of the buccal and lingual cortical bones. Material and Methods A total of 12 individuals from an initial group of 39 patients submitted to extraction of the unruptured lower third molars and grafting of an association of inorganic bovine bone matrix, organic bovine bone matrix, collagen and bone morphogenetic proteins (BMP) (Gen-Tech®) on one side and the contralateral sockets filled only by clot, returned to control after 5 years, and were submitted to CBCT. The distance from the crest of alveolar bone to the CEJ and the bone density (BD) were measured using the i-CAT Vision Software. Results The results showed that the distance from the crest of alveolar bone to the CEJ in the control group was similar to that observed before the exodontia; in the experimental group, this distance was smaller. Considering the BD measurement, a significantly higher density was observed in the experimental group (p<0.05). Conclusion Part of the biomaterial was not absorbed and allowed the stability of the evaluated parameters after 5 years, being able to be used as a bone substitute in the socket.

Lesiones cervicales no cariosas / Non-carious cervical lesions

El objetivo de este trabajo consiste en describir las distintas lesiones cervicales no cariosas, la abrasión, la erosión y la abfracción. Se desarrollarán en detalle su etiología, localización y características clínicas. Se mencionarán los diferentes procedimientos a realizar para su prevención y los materiales a utilizar para su restauración.

This article describes the different types of non-cariouscervical lesions, for example abrasion, erosionand abfraction. We will discuss their etiology, location and clinical features in detail. We will describe the procedures to prevent them, aswell as the materials used for their restoration.

External cervical resorption: diagnostic and treatment tips

ABSTRACT External cervical resorption is caused, almost exclusively, by dental trauma - especially those characterized by concussion - and is a dental disease to be diagnosed and treated accurately by endodontists. However, the vast majority of the cases is initially diagnosed by an orthodontist, due to the imaging possibilities in standardized documentations. Among the causes of external cervical resorption, it is common to mistakenly attribute it to orthodontic treatment, traumatic occlusion or even to chronic inflammatory periodontal disease. External cervical resorption is associated to dental trauma in several situations mentioned in this paper. In old cases, and eventually still nowadays, it may have been induced by internal tooth bleaching, which is increasingly less frequent in endodontically treated teeth. There are some tips to be followed and some care that must be taken during the diagnosis and treatment of external cervical resorption clinical cases. The present study lists foundations that will allow the professional to perform safely and accurately in each specific case. Some of these tips and care measures are of orthodontic nature.

RESUMO A reabsorção cervical externa é provocada, quase exclusivamente, pelo traumatismo dentário, especialmente os do tipo concussão. Ela constitui uma doença dentária a ser diagnosticada e tratada com precisão pelo endodontista, mas a grande maioria dos casos é inicialmente diagnosticada pelo ortodontista, em função das oportunidades imagiológicas nas documentações padronizadas. Entre as causas da reabsorção cervical externa, é comum atribuí-la equivocamente ao tratamento ortodôntico, à oclusão traumática ou, ainda, à doença periodontal inflamatória crônica. A reabsorção cervical externa está associada ao traumatismo dentário em várias situações mencionadas neste trabalho. Em casos mais antigos - e ainda hoje, eventualmente -, pode ter sido induzida pelo clareamento dentário interno, cada vez menos realizado em dentes endodonticamente tratados. Algumas dicas e cuidados devem ser tomados no diagnóstico e no tratamento dos casos clínicos de reabsorção cervical externa. No presente trabalho, são listados fundamentos para que o clínico possa atuar com segurança e precisão em cada caso, especificamente. Nessas dicas e cuidados, encontram-se alguns de natureza ortodôntica.

CBCT Post-Processing Tools to Manage the Progression of Invasive Cervical Resorption: A Case Report

Abstract This case report aimed to highlight the usefulness of cone beam computed tomography (CBCT) and its post-processing tools for the diagnosis, follow-up and treatment planning of invasive cervical resorption (ICR). A 16-year-old female patient was referred for periapical radiographic examination, which revealed an irregular but well demarcated radiolucency in the mandibular right central incisor. In addition, CBCT scanning was performed to distinguish between ICR and internal root resorption. After the diagnosis of ICR, the patient was advised to return shortly but did so only six years later. At that time, another CBCT scan was performed and CBCT registration and subtraction were done to document lesion progress. These imaging tools were able to show lesion progress and extent clearly and were fundamental for differential diagnosis and treatment decision.

Resumo Com este relato de caso clínico objetiva-se enfatizar a contribuição das ferramentas de pós-processamento aplicadas às imagens de tomografia computadorizada de feixe cônico (TCFC) no diagnóstico, acompanhamento e decisão do tratamento de reabsorção cervical invasiva (ICR). Paciente do sexo feminino, com 16 anos de idade foi encaminhada para realização de radiografia periapical e foi observada radiolucência irregular, na raiz do incisivo central inferior direito. A TCFC foi realizada no intuito de se obter diagnóstico diferencial entre ICR e reabsorção radicular interna. Após o diagnóstico de ICR, o paciente foi orientado a retornar em breve, mas o fez somente seis anos mais tarde. Fez-se assim outra tomografia e registro e subtração foram realizados para documentar a progressão da lesão. Essas ferramentas foram capazes de revelar claramente o progresso da lesão, sua real extensão e foram fundamentais para o diagnóstico diferencial e decisão de tratamento.

Identification of Apical and Cervical Curvature Radius of Human Molars

To determine the frequency of apical and cervical curvatures in human molars using the radius method and cone-beam computed tomography (CBCT) images. Four hundred images of mandibular and maxillary first and second molars were selected from a database of CBCT exams. The radius of curvature of curved root canals was measured using a circumcenter based on three mathematical points. Radii were classified according to the following scores: 0 - straight line; 1 - large radius (r>8 mm, mild curvature); 2 - intermediate radius (r>4 and r<8 mm, moderate curvature); and 3 - small radius (r≤4 mm, severe curvature). The frequency of curved root canals was analyzed according to root canal, root thirds, and coronal and sagittal planes, and assessed using the chi-square test (significance at α=0.05). Of the 1,200 evaluated root canals, 92.75% presented curved root canals in the apical third and 73.25% in the cervical third on coronal plane images; sagittal plane analysis yielded 89.75% of curved canals in the apical third and 77% in the cervical third. Root canals with a large radius were significantly more frequent when compared with the other categories, regardless of root third or plane. Most root canals of maxillary and mandibular first and second molars showed some degree of curvature in the apical and cervical thirds, regardless of the analyzed plane (coronal or sagittal).

Determinar a frequência de curvaturas apicais e cervicais em molares humanos usando o método do raio de curvatura e imagens de Tomografia Computadorizada de Feixe Cônico (TCFC). Quatrocentas imagens de primeiros e segundos molares superiores e inferiores foram selecionadas a partir de um banco de dados de exames de TCFC. O raio de curvatura dos canais foi medido usando um circuncentro com base em três pontos matemáticos e classificado de acordo com os seguintes escores: 0 - linha reta; 1 - raio grande (r > 8 mm, curvatura suave); 2 - raio intermediário (r > 4 e r < 8, curvatura moderada); 3 - raio pequeno (r ≤ 4 mm, curvatura severa). A frequência de curvaturas foi analisada em função do canal radicular, dos terços da raiz, e dos planos de avaliação (coronal e sagital); e avaliados usando o teste Qui-Quadrado (significância de α=0.05). Dos 1200 canais radiculares avaliados, 92,75% apresentaram curvatura no terço apical e 73,25% no terço cervical quando da análise no plano coronal; a análise do plano sagital revelou 89,75% de canais curvos no terço apical e 77% no terço cervical. Canais radiculares com curvatura suave foram significantemente mais frequentes quando comparados com as demais categorias, independentemente do terço radicular ou do plano. A maioria dos canais radiculares dos primeiros e segundos molares superiores e inferiores apresentou algum grau de curvatura nos terços apical e cervical, independentemente do plano analisado (coronal ou sagital).

Absence of Non-Carious Cervical Lesions (NCCLs) in a Chilean Pre-Columbian Sample with Severe Occlusal Tooth Wear / Ausencia de Lesiones Cervicales no Cariosas (NCCLs) en una Muestra Chilena Precolombina con Severo Desgaste Oclusal

This study evaluates the non-carious cervical lesions (NCCLs) and the occlusal tooth wear in a pre-Columbian sample (n= 67, adults) from San Pedro de Atacama (North of Chile, 400-1300 BCE). The cervical regions of tooth were observed for loss of enamel and/or dentine in order to identify them as NCCLs and the tooth wear was characterized by the Basic Erosive Wear Examination (BEWE) index. None of the individuals analyzed presented NCCLs, whereas the 98.5% (66/67) of them showed occlusal wear. The mean BEWE index was 2.5, indicating severe dental wear (3 being the highest possible score of BEWE). This lack of relation among severe tooth wear and NCCLs gives support to the idea of loss of crown height reduces cervical stress and develop of NCCLs in archaeological populations.

Este estudio evalúa las lesiones cervicales no cariosas (NCCLs) y el desgaste dental oclusal en una muestra precolombina (n= 67, adultos) de San Pedro de Atacama (Norte de Chile, 400-1300 AEC). Se analizó la perdida de esmalte y/o dentina en las áreas cervicales de los dientes con el propósito de identificarlas como NCCLs y el desgaste dental fue evaluado según el índice Basic Erosive Wear Examination (BEWE). Ninguno de los individuos analizados presentó NCCLs, mientras el 98,5% (66/67) de ellos mostró desgaste oclusal. El promedio del índice BEWE fue de 2,5, indicando severo desgaste dental (siendo 3 el puntaje más alto posible). La falta de relación entre severo desgaste dental y NCCLs apoya la idea que la pérdida de altura de las coronas reduce el estrés cervical y el desarrollo de NCCLs en poblaciones arqueológicas.

Prevalence and risk factors of non-carious cervical lesions related to occupational exposure to acid mists

This study evaluates the prevalence and risk factors of non-carious cervical lesions (NCCLs) in a Brazilian population of workers exposed and non-exposed to acid mists and chemical products. One hundred workers (46 exposed and 54 non-exposed) were evaluated in a Centro de Referência em Saúde do Trabalhador – CEREST (Worker’s Health Reference Center). The workers responded to questionnaires regarding their personal information and about alcohol consumption and tobacco use. A clinical examination was conducted to evaluate the presence of NCCLs, according to WHO parameters. Statistical analyses were performed by unconditional logistic regression and multiple linear regression, with the critical level of p < 0.05. NCCLs were significantly associated with age groups (18-34, 35-44, 45-68 years). The unconditional logistic regression showed that the presence of NCCLs was better explained by age group (OR = 4.04; CI 95% 1.77-9.22) and occupational exposure to acid mists and chemical products (OR = 3.84; CI 95% 1.10-13.49), whereas the linear multiple regression revealed that NCCLs were better explained by years of smoking (p = 0.01) and age group (p = 0.04). The prevalence of NCCLs in the study population was particularly high (76.84%), and the risk factors for NCCLs were age, exposure to acid mists and smoking habit. Controlling risk factors through preventive and educative measures, allied to the use of personal protective equipment to prevent the occupational exposure to acid mists, may contribute to minimizing the prevalence of NCCLs.

The clinical meaning of external cervical resorption in maxillary canine: transoperative dental trauma

External Cervical Resorption in maxillary canines with pulp vitality is frequently associated with dental trauma resulting from surgical procedures carried out to prepare the teeth for further orthodontic traction. Preparation procedures might surgically manipulate the cementoenamel junction or cause luxation of teeth due to applying excessive force or movement tests beyond the tolerance limits of periodontal ligament and cervical tissue structures. Dentin exposure at the cementoenamel junction triggers External Cervical Resorption as a result of inflammation followed by antigen recognition of dentin proteins. External Cervical Resorption is painless, does not induce pulpitis and develops slowly. The lesion is generally associated with and covered by gingival soft tissues which disguise normal clinical aspects, thereby leading to late diagnosis when the process is near pulp threshold. Endodontic treatment is recommended only if surgical procedures are rendered necessary in the pulp space; otherwise, External Cervical Resorption should be treated by conservative means: protecting the dental pulp and restoring function and esthetics of teeth whose pulp will remain in normal conditions. Unfortunately, there is a lack of well-grounded research evincing how often External Cervical Resorption associated with canines subjected to orthodontic traction occurs.

A reabsorção cervical externa em caninos superiores com vitalidade pulpar em sua quase totalidade está associada a traumatismo dentário decorrente de procedimentos cirúrgicos associado à preparação desse dente para ser tracionado ortodonticamente. Nessa preparação pode se manipular cirurgicamente a junção amelocementária ou luxar o dente com forças excessivas ou com testes de movimentação além dos limites de tolerância estrutural do ligamento periodontal e tecidos cervicais. A exposição dentinária na junção amelocementária é o estopim para se iniciar uma reabsorção cervical externa a partir de uma inflamação induzida na região seguida de reconhecimento antigênico das proteínas dentinárias. A reabsorção cervical externa é indolor, não induz pulpites e tem uma evolução lenta. Em geral, a lesão está associada e recoberta por tecidos moles gengivais que mantêm, por longos períodos, os aspectos clínicos normais, induzindo diagnósticos tardios, quando o processo se aproxima dos limites pulpares. O tratamento endodôntico está indicado apenas em função de procedimentos operatórios que se fazem necessários no espaço pulpar; caso contrário, a reabsorção cervical externa deve ser tratada de forma conservadora, protegendo a polpa dentária e restaurando a função e estética do dente que permanecerá com sua polpa normal. Infelizmente, não sabemos, com base em pesquisas de casuísticas bem estabelecidas, qual é a frequência da reabsorção cervical externa associada a caninos ortodonticamente tracionados.

Extreme root resorption associated with induced tooth movement: A protocol for clinical management

Cases in which teeth have only the cervical third remaining from orthodontically induced external root resorption, cast the following doubts: 1) What care should be taken to keep these teeth in mouth with the least risk possible? 2) What care should be taken with regards to reading of imaging exams, particularly in terms of accurately determining cervical root and bone loss? 3) Why is not endodontic treatment recommended in these cases? The present study aims at shedding light on the aforementioned topics so as to induce new insights into the theme.

Nos casos em que os dentes têm apenas o terço cervical remanescente de uma reabsorção radicular externa induzida ortodonticamente: 1) Quais seriam os cuidados para que permaneçam na boca, com o menor risco possível de perda? 2) Quais seriam os cuidados na interpretação imaginológica desses casos, quanto à determinação precisa da perda radicular e óssea cervical? 3) Por que o tratamento endodôntico não estaria indicado? No presente trabalho, procura-se esclarecer esses pontos e respondendo os questionamentos, para induzir novos insights sobre o assunto.

Analysis of correlation between initial alveolar bone density and apical root resorption after 12 months of orthodontic treatment without extraction

OBJECTIVE: The aim of the present study was to investigate the correlation between initial alveolar bone density of upper central incisors (ABD-UI) and external apical root resorption (EARR) after 12 months of orthodontic movement in cases without extraction. METHODS: A total of 47 orthodontic patients 11 years old or older were submitted to periapical radiography of upper incisors prior to treatment (T1) and after 12 months of treatment (T2). ABD-UI and EARR were measured by means of densitometry. RESULTS: No statistically significant correlation was found between initial ABD-UI and EARR at T2 (r = 0.149; p = 0.157). CONCLUSION: Based on the present findings, alveolar density assessed through periapical radiography is not predictive of root resorption after 12 months of orthodontic treatment in cases without extraction. .

OBJETIVO: avaliar a correlação entre a densidade óssea alveolar inicial dos incisivos centrais superiores (DOA-IS) e a reabsorção radicular apical externa (RRAE) após 12 meses de movimentação ortodôntica em casos sem extração. MÉTODOS: quarenta e sete pacientes ortodônticos (maiores que 11 anos) foram submetidos ao exame periapical dos incisivos superiores no pré-tratamento (T1) e 12 meses após (T2). Mensurou-se a RRAE no intervalo de 12 meses, bem como a densidade óssea alveolar inicial da região apical desses dentes por meio da fotodensitometria. RESULTADOS: não houve correlação estatisticamente significativa entre a DOA-IS inicial e a RRAE em T2 (r = 0,149; p = 0,157). CONCLUSÃO: a densidade alveolar avaliada pela radiografia periapical não se apresentou como fator de interferência ou preditivo para reabsorção radicular após 12 meses de tratamento ortodôntico sem extração. .

Comparative photoelastic study of dental and skeletal anchorages in the canine retraction

OBJECTIVE: To compare dental and skeletal anchorages in mandibular canine retraction by means of a stress distribution analysis. METHODS: A photoelastic model was produced from second molar to canine, without the first premolar, and mandibular canine retraction was simulated by a rubber band tied to two types of anchorage: dental anchorage, in the first molar attached to adjacent teeth, and skeletal anchorage with a hook simulating the mini-implant. The forces were applied 10 times and observed in a circular polariscope. The stresses located in the mandibular canine were recorded in 7 regions. The Mann-Whitney test was employed to compare the stress in each region and between both anchorage systems. The stresses in the mandibular canine periradicular regions were compared by the Kruskal-Wallis test. RESULTS: Stresses were similar in the cervical region and the middle third. In the apical third, the stresses associated with skeletal anchorage were higher than the stresses associated with dental anchorage. The results of the Kruskal-Wallis test showed that the highest stresses were identified in the cervical-distal, apical-distal, and apex regions with the use of dental anchorage, and in the apical-distal, apical-mesial, cervical-distal, and apex regions with the use of skeletal anchorage. CONCLUSIONS: The use of skeletal anchorage in canine retraction caused greater stress in the apical third than the use of dental anchorage, which indicates an intrusive component resulting from the direction of the force due to the position of the mini-implant and the bracket hook of the canine. .

OBJETIVO: comparar as ancoragens dentária e esquelética na retração do canino inferior, por meio do estudo da distribuição de tensões. MÉTODOS: foi confeccionado um modelo fotoelástico de segundo molar a canino, sem o primeiro pré-molar, e simulada a retração do canino inferior com elástico preso a dois tipos de ancoragem: dentária, no primeiro molar conjugado aos dentes adjacentes; e ancoragem esquelética, em gancho simulando o mini-implante. As forças foram aplicadas 10 vezes e observadas no polariscópio circular. As tensões no canino inferior foram registradas em 7 regiões. O teste de Mann-Whitney foi aplicado para comparar as tensões em cada região, considerando os dois sistemas de ancoragem. As tensões nas regiões perirradiculares do canino foram comparadas pelo teste de Kruskal-Wallis. RESULTADOS: as tensões foram similares tanto na região cervical quanto no terço médio. No terço apical, as tensões associadas à ancoragem esquelética foram maiores que as tensões associadas à ancoragem dentária. Os resultados do teste de Kruskal-Wallis mostraram que as maiores tensões foram identificadas nas regiões cervicodistal, apicodistal e na região do ápice com o uso da ancoragem dentária; e com o uso da ancoragem esquelética, as maiores tensões se localizaram nas regiões apicodistal, apicomesial, cervicodistal e no ápice. CONCLUSÃO: o uso de ancoragem esquelética na retração promoveu maior tensão no terço apical do que o uso da ancoragem dentária, indicando um componente intrusivo devido à direção da força decorrente da posição do mini-implante e do gancho do braquete do canino. .

Force distribution is more important than its intensity!

A common question about root resorption is raised in orthodontic practice: What is more important, the intensity of force or its distribution along the root, periodontal and alveolar structures? Diffuse distribution of forces applied to periodontal tissues during tooth movement tends not to promote neither extensive areas of cell matrix hyalinization nor significant death of cementoblasts that lead to root resorption. However, focal distribution or concentration of forces within a restricted area - as it occurs in tipping movements, even with forces of lower intensity - tend to induce extensive areas of hyalinization and focal death of cementoblasts, which is commonly associated with root resorption. In tipping movements, the apical regions tend to concentrate more forces in addition to wounding the cementoblasts due to the smaller dimension of their root structure as well as their cone shape. For this reason, there is an increase in root resorption. In the cervical region, on the other hand, the large area resulting from a large diameter and bone crown deflection tends to reduce the effects of forces, even when they are more concentrated, thus rarely inducing death of cementoblasts and root resorption.

Um questionamento comum sobre as reabsorções radiculares na prática ortodôntica: "O que é mais importante? A intensidade das forças aplicadas ou sua distribuição ao longo das estruturas radiculares, periodontais e alveolares?" A distribuição difusa das forças aplicadas sobre os tecidos periodontais durante o movimento dentário de corpo tende a não promover extensas áreas de hialinização da matriz extracelular, nem morte significativa de cementoblastos que levariam à reabsorção radicular. Porém, a distribuição focal ou concentração de forças - como nas inclinações, mesmo nas de menor intensidade - em uma área restrita tende a induzir áreas extensas de hialinização e morte focal de cementoblastos, associando-se mais comumente à reabsorção radicular. Nos movimentos de inclinação, as áreas apicais, por sua menor dimensão da estrutura radicular e sua forma cônica, tendem a concentrar mais ainda as forças e lesar cementoblastos, aumentando a frequência das reabsorções radiculares. Na região cervical, a maior área decorrente do maior diâmetro e a deflexão óssea da crista óssea tendem a reduzir os efeitos das forças, mesmo quando mais concentradas, muito raramente induzindo a morte de cementoblastos e reabsorções radiculares.