Tercer molar heterotópico, etiología y manejo quirúrgico / Heterotopic third molar, etiology and surgical management

Los terceros molares heterotópicos son dientes que se encuentran incluidos en los maxilares y la mandíbula distantes a su sitio de erupción habitual. Su etiología no está bien definida y existen diversas teorías. Estos dientes pueden aparecer en diferentes zonas de las estructuras óseas, teniendo predilección por la mandíbula. Suelen aparecer entre la segunda y la séptima década de la vida, la mayoría de los casos son hallazgos imagenológicos en la consulta odontológica. El tercer molar mandibular es el diente que presenta heterotopía con mayor frecuencia, siendo su localización habitual en rama mandibular y en la región subcondílea. El quiste dentígero es la patología asociada más común. Presentamos un caso de tercer molar heterotópico en rama mandibular derecha de larga evolución, relacionado a un quiste dentígero, el cual se manejó bajo anestesia regional. Se describe la etiología, técnica quirúrgica y consideraciones especiales relacionados con los dientes heterotópicos (AU)

Heterotopic third molars are teeth that are embedded in the maxilla and mandible, remote from their usual eruption site. Its etiology is not well defined and there are various theories at the moment. These teeth can appear in different areas of the bone's structures, having a predilection for the jaw. They usually appear between the second and seventh decade of life, and in most cases are imaging findings. The mandibular third molar is the tooth with the most frequent heterotopia, being its usual location in the mandibular branch and in the subcondylar region. The dentigerous cyst is the most common associated pathology. We present a case of a long evolution heterotopic third molar in the right mandibular branch, related to a dentigerous cyst which was managed under local anesthesia. The etiology, surgical technique and special considerations related to heterotopic teeth are described (AU)

Has the literature thoroughly categorized the lower third molars? A new classification of the various lower third molar root forms for a better understanding of their morphology / ¿La literatura ha categorizado minuciosamente los terceros molares inferiores? Una nueva clasificación de las diversas formas radiculares del tercer molar inferior para una mejor comprensión de su morfología

SUMMARY: Impacted lower third molars (IL3M) have different root shapes and numbers. This study aimed to create a classification for IL3M root forms, that should aid in understanding roots morphology. A retrospective cross-sectional study on patients had IL3M at the university clinics between 2017 and 2019. Panoramic radiographs were retrieved to classify the roots into fused roots (FR): one or two roots connected from furcation to apices, and separated roots (SR): two or more roots not connected from furcation to apical third, and each type has different forms. Statistical analysis was done by Chi-Square test. Five-hundred patients, males (54.6 %) and females (45.4 %) were included. SR were in 591 teeth (75.5 %), and FR in 192 teeth (24.5 %). Statistically significant associations emerged between SR and males (60 %) and between FR and females (66 %) (p = .000). SR forms were straight (45.8 %), joined roots (28.2 %), one straight and one curved (13.3 %), roots curved distal (9.1 %), roots curved mesial (2.5 %), and more than two roots (0.3 %). FR forms were straight (87.5 %), curved distal (9.4 %), S-shaped (2.1 %), and curved mesial (1 %). The common angulations of IL3M with SR were vertical (39 %) followed by mesioangular (25.7 %), while FR were mostly vertical (39.1 %) or horizontal (23.9 %). The classification is applicable on panoramic radiographs, and complements Winter and Pell & Gregory to provide a better description of IL3M status by adding root morphology to the angulation, occlusal, and ramus relationship.

Los terceros molares inferiores impactados (3MII) tienen diferentes formas y números de raíces. Este estudio tuvo como objetivo crear una clasificación para las formas de raíz 3MII, que debería ayudar a comprender la morfología de las raíces. Realizamos un estudio transversal retrospectivo de pacientes con 3MII en las clínicas universitarias entre 2017 y 2019. Se recuperaron radiografías panorámicas para clasificar las raíces en raíces fusionadas (RF): una o dos raíces conectadas desde la zona de furca a los ápices y raíces separadas (RS): dos o más raíces no conectadas desde la bifurcación al tercio apical, y cada tipo con formas diferentes. El análisis estadístico se realizó mediante la prueba Chi-Cuadrado. Se incluyeron 500 pacientes, hombres (54,6 %) y mujeres (45,4 %). RS se observó en 591 dientes (75,5 %) y RF en 192 dientes (24,5 %). Surgieron asociaciones estadísticamente significativas entre RS y hombres (60 %) y entre RF y mujeres (66 %) (p = .000). Las formas de RS eran rectas (45,8 %), raíces unidas (28,2 %), una recta y una curva (13,3 %), raíces curvas distales (9,1 %), raíces curvas mesiales (2,5 %) y más de dos raíces (0,3 %).). Las formas RF eran rectas (87,5 %), curvas distales (9,4 %), en forma de S (2,1 %) y curvas mesiales (1 %). Las angulaciones comunes de 3MII con RS fueron verticales (39 %), seguidas de mesioangular (25,7 %), mientras que RF fueron mayoritariamente verticales (39,1 %) u horizontales (23,9 %). La clasificación es aplicable en radiografías panorámicas y complementa a Winter y Pell & Gregory para proporcionar una mejor descripción del estado de 3MII al agregar la morfología de la raíz a la relación de angulación, oclusal y rama.

Aplicación de las radiografías para la estimación forense de la edad dental: una perspectiva bioética / Application of X-rays for the forensic estimation of dental age: a bioethical perspective

Uno de los aspectos más relevantes del actual mundo globalizado reside en las incesantes corrientes mi-gratorias, donde un gran número de menores de edad se encuentran desprotegidos de sus derechos esen-ciales. En tales contextos, la estimación forense de la edad se sustenta en la aplicación multidisciplinaria de diferentes criterios científicos validados interna-cionalmente. La exposición a la radiación ionizante es común en técnicas destinadas a analizar los periodos de mineralización y cierre apical de la dentición de-finitiva, generando controversias respecto a la inva-sión que ello supone sobre la salud de las personas involucradas, cuestionándose que el acto pericial realizado no redunda en beneficios terapéuticos que justifiquen tal exposición. En ámbitos penales donde se busca dilucidar la mayoría de edad de jóvenes que han delinquido, la evaluación de los terceros molares representa una estrategia crucial para estimarla, constituyendo el índice de madurez (I3M) desarrolla-do por Cameriere et al., el método cuantitativo más di-fundido. El presente artículo reflexiona sobre aspec-tos bioéticos inherentes a tales procesos, poniendo énfasis en la autonomía, beneficencia, no maleficen-cia y justicia como principios insustituibles que deben respetarse en ámbitos afines a la edad forense (AU)

One of the most relevant aspects of the current globalized world lies in the incessant migratory flows, where a large number of minors are unprotected of their essential rights. In such contexts, the forensic estimation of age is based on the multidisciplinary application of different internationally validated scientific criteria. Exposure to ionizing radiation is common in techniques designed to analyze the periods of mineralization and apical closure of the final dentition, generating controversies regarding the invasion that this implies on the health of the people involved, questioning whether the expert act carried out does not redound in therapeutic benefits justifying such exposure. In criminal settings where it is sought to elucidate the age of majority of young people who have committed crimes, the evaluation of third molars represents a crucial strategy to estimate it, constituting the maturity index (I3M) developed by Cameriere et al., the most widespread quantitative method. This article reflects on bioethical aspects inherent to such processes, emphasizing in the autonomy, beneficence, non-maleficence and justice as irreplaceable principles that must be respected in areas related to forensic age (AU)

Remoción diferida de un tercer molar superior impulsado a la región infratemporal / Deferred removal of a third upper molar driven to the infratemporal region

La cirugía de los terceros molares retenidos puede ser considerada una intervención de rutina para el cirujano bucomaxilofacial. Como todo procedimien-to quirúrgico, puede presentar complicaciones intra y postoperatorias. Las más frecuentes son el dolor, edema, trismus, hemorragia y fracturas de las piezas dentarias a extraer, o de las tablas óseas. Pero tam-bién se pueden presentar otras complicaciones ines-peradas, como la impulsión o desplazamiento de la pieza dentaria a espacios anatómicos vecinos, entre los que podemos encontrar al espacio pterigomandi-bular, la celda submaxilar, el seno maxilar, el espacio infratemporal, según se trate de terceros molares retenidos inferiores o superiores. En el presente ar-tículo, se describe una situación clínica de un tercer molar superior, que fue accidentalmente impulsado a la región infratemporal, y removido en una segunda cirugía realizada 3 semanas después del primer in-tento de exodoncia. Se analizan también los estudios preoperatorios para su correcto diagnóstico, y las maniobras clínicas e instrumentales tendientes a po-sibilitar su remoción minimizando las complicaciones intra y postquirúrgicas (AU)

Surgery of retained third molars can be considered a routine intervention for the oral surgeon. Like any surgical procedure, it can present intra and posto-perative complications. The most frequent are pain, edema, trismus, hemorrhage and fractures of the teeth to be extracted or of the bone tables. But other unexpected complications can also occur, such as the impulsion or displacement of the tooth to neighbo-ring anatomical spaces, among which we can find the pterygomandibular space, the submaxillary cell, the maxillary sinus, the buccal space, the infratemporal space and the lateral pharyngeal space, depending on whether they are lower or upper retained third mo-lars. In this article, the clinical case of a third upper molar is described, which was accidentally driven to the infratemporal region, which was removed in a second surgery performed 3 weeks after the first attempt at exodontics. It should be noted the impor-tance of diagnostic imaging as an indispensable com-plement to the correct location of the displaced tooth and its subsequent removal (AU)

Utilização e percepção da tomografia computadorizada de feixe cônico por especialistas em cirurgia e traumatologia bucomaxilofacial para avaliação de terceiros molares inferiores impactados / Use and perception of cone beam computed tomography by oral & maxillofacial surgeons for impacted lower third molars evaluation

Objetivo: conhecer o perfil demográfico e as características que levam à solicitação de tomografia computa-dorizada de feixe cônico (TCFC) pelos especialistas em Cirurgia e Traumatologia Bucomaxilofacial (CTBMF) do estado do Rio Grande do Sul, para diagnóstico e planejamento cirúrgico de terceiros molares inferiores (3MI) impactados. Métodos: foram enviados questionários eletrônicos para todos os especialistas em CTBMF do RS. O questionário compreendia perguntas demográficas, clínicas e imaginológicas. O teste Qui-Quadra-do foi utilizado para verificar a associação entre as variáveis. Resultados: 115 questionários foram respondi-dos.O exame mais solicitado foi a panorâmica (95%). A TCFC foi solicitada por 50 especialistas (30 utilizam software). Localização do canal mandibular, dilaceração radicular e reabsorção do segundo molar são os aspectos mais avaliados na TCFC (P < 0,05); já o contato da raiz com o canal mandibular foi dito ser avaliado nos dois exames. Complicações permanentes foram relatadas por 21 especialistas, associadas a profissionais com maior tempo de graduação e/ou especialização (P < 0,05), mas não com o tipo de exame solicitado (P > 0,05). Na percepção dos especialistas, a TCFC tem papel importante em casos de alta complexidade. Con-clusão: a panorâmica ainda é o exame mais utilizado para avaliação de 3MI impactados pelos especialistas em CTBMF do RS, porém a TCFC tem sido solicitada para complementação do diagnóstico e planejamento e como meio de segurança jurídica do profissional.(AU)

Objective: to recognize the demographic profile and the characteristics that lead to the request of cone beam computed tomography (CBCT) by Oral & Maxillofacial (OMF) Surgeons in the state of RS for the diagnosis and surgical planning of impacted lower third molars (3LM). Methods: electronic questionnaires were sent to all OMF surgeons in RS. The questionnaire comprised demographic, clinical, and imaging questions. The chi-square test was used to verify the association between variables. Results: 115 questionnaires were answered. The most requested exam was the panoramic (95%). CBCT was requested by 50 specialists (30 use software). Localization of the mandibular canal, root dilaceration, and resorption of the second molar are the most evaluated aspects in the CBCT (P <0.05); the contact of the root with the mandibular canal was said to be evaluated in both exams. Permanent complications were reported by 21 OMF surgeons, and were related to the time of graduation and/or specialization (P < 0.05), but not to the type of exam (P > 0.05). In the OMF surgeons' perception, the CBCT has an important role in cases of high complexity. Conclusion: panoramic radiograph still is the most used exam for the assessment of impacted 3LM by OMF surgeons in RS, however, CBCT has been requested to complement the diagnosis and treatment plan, and as a means of professional legal security.(AU)

Ten reasons to not ignore the third molar

ABSTRACT Introduction: The third molars are forgotten because they are the last in the dental arch, they do not directly influence the smile and they appear only in adolescence, when they do. Objectives: 1) to provide the clinician with a "checklist" to assess and diagnose changes to be screened in the third molar region in new patients; 2) to reveal the importance of not discharging the patient submitted to any dental treatment without first analyzing the third molars region clinically and on imaging examinations, since many diseases are associated to them. Result: A list of 10 situations that cover all diagnostic possibilities involving the third molars is presented. Conclusion: Adopting this protocol is a matter of habit, since the need is fundamental. The next professional assisting your patient may ask: "Did he not request examinations for the third molars?".

RESUMO Introdução: Os terceiros molares são esquecidos por serem os últimos dentes na arcada dentária, por não influenciarem diretamente no sorriso e por aparecerem apenas na adolescência - quando aparecem. Objetivos: 1) Fornecer ao clínico um checklist de conferência e diagnóstico de alterações a serem checadas na região dos terceiros molares em novos pacientes; e 2) Destacar a importância de não dar alta ao paciente submetido a qualquer tratamento odontológico sem antes analisar, clínica e imagiologicamente, a região dos terceiros molares, pois muitas doenças estão a eles associadas. Resultado: Criou-se uma lista de 10 situações que englobam todas as possibilidades diagnósticas envolvendo os terceiros molares. Conclusão: Adotar esse protocolo é uma questão de hábito, pois a necessidade é imperiosa. O próximo profissional a atender o seu paciente vai perguntar: "Ele não solicitou exames para os terceiros molares?".

Impact of Early Loss of Lower First Permanent Molars on Third Molar Development and Position

ABSTRACT Objective: To evaluate the effects of unilateral loss of the lower first permanent molar (L6) on the position and development of the lower third molar (L8). Material and Methods: Fifty-four panoramic radiographs of subjects with unilateral loss of L6 were examined. The L8 on the side of the L6 loss was compared with the L8 in the hemiarch without L6 loss (contralateral). The effect of L6 loss on the positioning of L8 was examined in all the samples (n=54), whereas the effect on the development of the third molar was examined in 38 patients with L8 with incomplete root formation. The Signs statistical test was used to evaluate the comparison between loss and contralateral hemiarches. Results: In 20 (37%) of 54 subjects, the L8 was better positioned in the hemiarch with loss of the lower first molar (p<0.001) compared with the control side. In the remaining 34 subjects, no difference was found. When only the L8 considered as impacted on the control side was examined (n=30), the cases with better positioning on the side with L6 loss increased to 66.6% (p<0.001). Conclusion: The loss of lower first molars improves the position of the lower third molar during its active eruption, mainly when the lower third molar is impacted. However, L6 loss does not affect the root development of lower third molars.

Coronectomia: alternativa à exodontia de terceiros molares inferiores / Coronectomy: an alternative to third lower molar extraction

Objetivo: relatar um caso clínico de coronectomia com acompanhamento pós-operatório de 15 meses. Relatode caso: a coronectomia é uma alternativa de tratamento para terceiros molares inferiores (3MI) impactadosque apresentam proximidade com o canal mandibular, minimizando o risco de morbidade neurossensorial.A técnica consiste em remover apenas a coroa dentária (na junção amelocementária) com retençãointencional das raízes e da polpa, evitando o dano direto ou indireto ao nervo alveolar inferior (NAI). Oprocedimento foi realizado em paciente adulto do gênero masculino com 3MI impactados. A radiografia panorâmicamostrava o escurecimento dos ápices radiculares, sugerindo íntima relação das raízes com o canalmandibular. No acompanhamento pós-operatório imediato, o paciente retornou sem sintomatologia dolorosa,sem edema facial significativo, apresentando boa cicatrização e sem relato de perda de sensibilidade nemde disfunção mastigatória. No acompanhamento radiográfico, foi verificada neoformação óssea adjacenteaos remanescentes radiculares. Considerações finais: a coronectomia mostrou-se um procedimento simples,eficaz e seguro para diminuir o risco de injúria ao NAI durante o tratamento dos 3MI.(AU)

Objective: to report a case of coronectomy with follow-up of 15 months. Case report: coronectomy is an alternative treatment for impacted lower third molars (3ML) which are close to the mandibular canal, minimizing the risk of sensorineural morbidity. The technique consists of removing only the dental crown (at the cementoenamel junction) with intentional retention of the roots and pulp, avoiding direct or indirect damage to the inferior alveolar nerve (IAN). The procedure was performed on an adult male patient with impacted 3ML. Panoramic radiograph showed darkening of the roots, suggesting a close relationship between the roots and the mandibular canal. At immediate postoperative follow-up, the patient returned with no painful symptoms, no significant facial edema, good healing, and no loss of sensation or masticatory dysfunction. Radiographic follow-up showed bone neoformation adjacent to the root remnants. Final considerations: coronectomy has been shown to be a simple, effective and safe procedure to decrease the risk of injury to IAN during 3MI treatment.(AU)

The ability of orthodontists and maxillofacial surgeons in predicting spontaneous eruption of mandibular third molar using panoramic serial radiographs

ABSTRACT Objective: To evaluate the skill of orthodontists and oral/maxillofacial surgeons (OMFS) in providing a prognosis of mandibular third molars spontaneously erupted, through follow-up panoramic analysis. Methods: 22 orthodontic patients treated without extraction, presenting spontaneously erupted mandibular third molars (n = 44) were analyzed through panoramic serial radiographs. The first panoramic radiograph was obtained just after orthodontic treatment (PR1), in patients aging from 13 to 19 years. A second panoramic radiograph (PR2), was obtained in average two years later. The radiographs were randomly analyzed by 54 specialists, 27 orthodontists and 27 OMFS, to obtain the opinion about the approach to be adopted to these teeth in PR1. Then, another opinion was collected by adding a serial radiograph (PR1+2). Results: The concordance of the answers was moderate for OMFS (Kappa 0.44; p< 0.0001) and significant for orthodontists (Kappa 0.39; p< 0.0001). In the analysis of the first radiograph (PR1) of the spontaneously erupted molars, OMFS indicated extraction in 44.5% of cases, while orthodontists indicated in 42%, with no difference between groups (p= 0.22). In PR1+2 analysis, orthodontists maintained the same level of extraction indication (45.6%, p= 0.08), while surgeons indicated more extractions (63.2%, p< 0.0001). Conclusions: Orthodontists and OMFS were not able to predict the eruption of the third molars that have erupted spontaneously. Both indicated extractions around half of the third molars. A follow-up analysis, including one more radiograph, did not improve the accuracy of prognosis among orthodontists and worsened for OMFS.

RESUMO Objetivo: Avaliar a habilidade de ortodontistas e cirurgiões bucomaxilofaciais (CBMF) em propor um prognóstico para terceiros molares inferiores. Métodos: Foram analisados 22 pacientes tratados ortodonticamente sem extração, cujos terceiros molares inferiores irrompidos espontaneamente (n= 44) foram avaliados por meio de radiografias panorâmicas seriadas. A primeira radiografia foi obtida logo após o tratamento ortodôntico (RX1), entre 13 e 19 anos de idade. A segunda radiografia (RX2) foi avaliada dois anos depois, em média. As radiografias foram analisadas aleatoriamente por 54 especialistas, 27 ortodontistas e 27 CBMFs, para obter sua opinião sobre a abordagem a ser adotada na RX1. Em seguida, outra opinião foi coletada adicionando-se a segunda radiografia seriada (RX1+2). Resultados: A concordância das respostas foi moderada para os CBMFs (Kappa = 0,44; p< 0,0001) e significativa para os ortodontistas (Kappa = 0,39; p< 0,0001). Após analisar apenas a primeira radiografia (RX1) dos molares antes deles irromperem espontaneamente, os CBMFs indicaram extração em 44,5% dos casos; enquanto os ortodontistas, em 42%, sem diferença entre os grupos (p= 0,22). Na análise de RX1+2, os ortodontistas mantiveram o mesmo nível de indicação de extração (45,6%, p= 0,08), enquanto os cirurgiões passaram a indicar mais extrações (63,2%, p< 0,0001). Conclusões: Ortodontistas e CBMFs não foram capazes de predizer a erupção de terceiros molares por meio da análise de uma única radiografia panorâmica, indicando extrações em cerca da metade dos terceiros molares examinados. Uma análise de acompanhamento, incluindo mais uma radiografia, não melhorou a precisão do prognóstico entre os ortodontistas, e piorou entre os CBMFs.

Prevalencia y análisis descriptivo de los terceros molares en un servicio odontológico del Área Metropolitana de Buenos Aires / Prevalence and descriptive analysis of third molars in a dentistry service in the Metropolitan Area of Buenos Aires

Objetivo: Evaluar la prevalencia y el patrón de reten- ción ósea de los terceros molares en pacientes que concurrie- ron a un servicio de urgencias y orientación de pacientes en el Área Metropolitana de Buenos Aires. Materiales y métodos: Se realizó un estudio obser- vacional retrospectivo en el que se evaluaron radiografías pa- norámicas de pacientes mayores de 18 años que concurrieron a un servicio de urgencias en el Área Metropolitana de Bue- nos Aires. Resultados: Fueron evaluadas 949 radiografías pano- rámicas. En 347 casos, se presentó al menos un tercer molar retenido. Entre los 1878 terceros molares registrados, hubo 768 retenidos (41%). Según la clasificación de Gregory y Pell, la ubicación más frecuente de los terceros molares retenidos inferiores fue la IIA (28%), y de los superiores, la C (54%). La angulación más frecuente fue la vertical (62%). En el 9% de los casos estudiados, se encontró una radiolucidez asociada al tercer molar mayor a 3 mm. No se encontró diferencia signifi- cativa en la prevalencia de retención según el sexo. Conclusiones: La prevalencia de retención fue mayor en el maxilar inferior que en el superior. La posición más fre- cuente fue la vertical. No se encontraron diferencias significa- tivas en cuanto a la distribución según el sexo (AU)

Aim: To evaluate the prevalence and pattern of bone re- tention of third molars in patients attending a patient orienta- tion and urgency service in the metropolitan area of Buenos Aires City. Materials and methods: This retrospective observa- tional study was conducted in a department of dental urgency in the city of Buenos Aires where we evaluate radiografic or- topantomograms. Results: 949 panoramic radiographs were evaluated. In 347 there was at least one third molar retained. Within the 1878 third molars registered, there were 768 retained (41%). In the lower retained third molars the most frequent location corresponded to the IIA location (28%) and in the upper ones it corresponded to the C location (54%) according to Gregory & Pell. The vertical position was the most frecquent (62%). A radiolucency associated with the third molar greater than 3 mm was found in 9% of the cases studied. No significant difference was found in the prevalence of retention according to sex. Conclusions: The prevalence of retention was higher in the lower than in the upper jaw, the vertical position being the most frequent. No significant difference was found in the distribution by sex (AU)

Evaluación radiográfica de la presencia/agenesia de terceros molares en una población infantil Mexicana / Radiographic Evaluation of the Presence/Agenesis of Third Molars in a Mexican Child Population

RESUMEN En el ser humano, el tercer molar es el órgano dentario que más variaciones presenta durante su desarrollo embriológico, y es causa de diversas alteraciones y malestares durante su proceso de erupción. Se ha señalado que la agenesia del tercer molar tiene una prevalencia entre 9 y 37%. El objetivo del presente estudio transversal comparativo fue evaluar radiográficamente la presencia/ausencia de gérmenes de terceros molares (G3M) en pacientes pediátricos de origen mexicano. Se analizaron 513 radiografías panorámicas de pacientes que asistieron al Posgrado en Estomatología Pediátrica de la Universidad Autónoma de San Luis Potosí (México), durante los años 2011 a 2017. Se tomaron como criterios de inclusión, pacientes entre los 7 y 18 años de edad, sexo indistinto; se excluyeron pacientes con antecedentes de extracción de alguno de los terceros molares, tratamiento ortodóntico previo, enfermedades congénitas y/o síndromes asociados. Se compararon las frecuencias y prevalencias de agenesia de terceros molares, en total y por cuadrantes, comparando por sexo y grupo de edad. 245 radiografías panorámicas correspondieron al sexo femenino y 268 al masculino. La prevalencia total de agenesia del G3M fue estimada en casi 56%, y el grupo de edad de 7-8 años mostró el mayor porcentaje; sin embargo, cuando este grupo de edad se excluyó del análisis, dicha prevalencia disminuyó a 27.3%. Los cuadrantes mandibulares mostraron mayor porcentaje de agenesia. No hubo diferencia estadística significativa en la comparación por sexo. La prevalencia total de agenesia del G3M reportada en el presente estudio se encuentra muy por encima de los parámetros internacionales. Es muy posible que la falta de visualización radiográfica de agenesia de los terceros molares haya sido errónea en algunos casos debido a la ausencia frecuente de indicios de calcificación de este diente durante las edades tempranas (7-8 años). El análisis ajustado proporcionó un valor de prevalencia más acorde con los estándares reconocidos por la literatura dental.

ABSTRACT In the human being, third molar is the tooth that exhibits more variants during its embryologic development, usually causing diverse anomalies and discomfort when erupting to the oral cavity. It has been pointed out that the prevalence of third molar agenesis is between 9 to 37%. The aim of the present comparative cross- sectional study was to radiographically assess the presence/absence of third molar germs (G3M) in a sample of pediatric patients of Mexican origin. A total of 513 panoramic radiographs were analyzed from patients attending the Pediatric Dentistry Postgraduate Program ( San Luis Potosí University, México), during the years 2011 to 2017. Inclusion criteria were patients between 7 and 18 years old, any gender; children with antecedents of a third molar extraction, previous orthodontic treatment, or with an associated congenital or systemic condition were excluded. Total prevalence G3M agenesis was calculated. Then, statistical comparisons of agenesia proportions per dental quadrant, gender, and age group were performed. 245 panoramic radiographs corresponded to the female gender, while 268 belonged to the male gender. The total prevalence of G3M agenesia was estimated in nearly 56%, and the 7-8 years old group exhibited the highest proportion; however, when this age group was excluded from the analysis, such prevalence decreased to 27.3%. Both mandibular quadrants showed higher proportions of G3M agenesia. There were no significant differences between genders. The total prevalence reported in the present study was found to be well above regarding the international parameters. It is quite possible that lack of radiographic visualization of G3M had been inaccurate in some cases due to the common absence of calcification traces from those teeth during early ages (7-8 years old). The adjusted analysis provided a prevalence value more in line with the recognized standards in the dental literature.

Estudio de la relación de los terceros molares superiores retenidos y el seno maxilar en radiografías panorámicas y tomografía (CBCT) / Study of the relationship of retained upper third molars and maxillary sinus in panoramic radiographs and tomography (CBCT)

Objetivo: Evaluar la eficacia de la radiografía panorámica para establecer la relación de los terceros molares superiores y la cortical inferior del seno maxilar, en comparación con la tomografía computarizada de haz cónico (CBCT). Material y métodos: El trabajo incluyó 72 pacientes, se estudiaron 34 terceros molares superiores retenidos izquierdos y 38 derechos. Se realizaron mediciones con el programa para establecer la distancia entre la cortical inferior del seno maxilar y el ápice del tercer molar superior a partir de la imagen de la radiografía panorámica en lo que se estableció como parámetros: «a distancia, en contacto y dentro del piso de seno maxilar¼. Luego, con los cortes oblicuos o paraaxiales de la tomografía computarizada (CBCT) se observó la verdadera ubicación en el plano bucopalatino. Resultados: Del total de los terceros molares superiores 34 fueron izquierdas (47.22%) y 38 derechas (52.78%). En la Rx. Panorámica, 18 casos (25%) se encontraron a distancia al seno maxilar, 12 en contacto (16.7%) y 42 por dentro (58.3%) del seno maxilar. En la tomografía se observaron 20 casos (27.8%) a distancia del conducto, 16 (22.2%) en contacto y 36 (50%) por dentro del seno maxilar. Se observaron diferencias estadísticamente significativas (p < 0.05) entre la Rx. panorámica y la tomografía (CBCT) de los terceros molares que se hallan por dentro del seno maxilar. Conclusión: A partir de los resultados obtenidos, podemos establecer que la radiografía panorámica no permite conocer la verdadera relación entre la cortical inferior del seno maxilar y los terceros molares superiores (AU)

Objective: To evaluate the effectiveness of panoramic radiography to establish the relationship of the upper third molars and the inferior cortical of the maxillary sinus, in comparison with the Cone Beam Computed Tomography (CBCT). Material and methods: The work included 72 patients, 34 upper left maxillary molars and 38 rights were studied. Measurements were made with the program to establish the distance between the lower cortex of the maxillary sinus and the apex of the upper third molar from the image of the panoramic radiograph in what was established as parameters: «at a distance, in contact and inside the floor of maxillary sinus¼. Then with the oblique or paraaxial slices of the computed tomography (CBCT) the true location in the bucco-palatal plane was observed. Results: Of the total upper third molars, 34 were left (47.22%) and 38 right (52.78%). In the panoramic X-ray 18 cases (25%) were found at distance to the maxillary sinus, 12 in contact (16.7%) and 42 inside (58.3%) of the maxillary sinus. The tomography showed 20 cases (27.8%) at a distance from the canal, 16 (22.2%) in contact and 36 (50%) inside the maxillary sinus. Statistically significant differences were observed (p < 0.05) between the Rx. panoramic and tomography (CBCT) of the third molars that are inside the maxillary sinus. Conclusion: From the results obtained, we can establish that the panoramic radiograph does not allow knowing the true relationship between the inferior cortical of the maxillary sinus and the upper third molars (AU)

Análisis de concordancia de tres clasificaciones de terceros molares mandibulares retenidos / Agreement analysis of three mandibular third molar retention classifications

Resumen Introducción: Las clasificaciones de Pell y Gregory y de Winter son básicas en la categorización de terceros molares; la clasificación de Sánchez Torres es usada en México, pero no había sido evaluada previamente. Objetivo: Evaluar el grado de acuerdo en la valoración radiográfica de terceros molares mandibulares impactados, con el empleo de tres clasificaciones: Pell y Gregory, Winter y Sánchez Torres. Método: Estudio observacional, descriptivo, de concordancia interobservador, que incluyó a 10 cirujanos orales y maxilofaciales y 10 residentes en formación, quienes registraron la categorización radiográfica de terceros molares mandibulares (izquierdos y derechos) de acuerdo con las clasificaciones de Pell y Gregory, Sánchez Torres y Winter. Se evaluó el grado de acuerdo entre observadores mediante la prueba de kappa de Fleiss. Resultados: La clasificación de Pell y Gregory obtuvo el menor grado de acuerdo (kappa = 0.05 y 0.185), seguida de la clasificación de Sánchez Torres (kappa = 0.125 y 0.326); el mejor valor lo obtuvo la clasificación de Winter, con kappa = 0.28 y 0.636 para cirujanos orales y maxilofaciales y residentes en formación, respectivamente. Conclusión: La clasificación de Winter mostró un grado de acuerdo aceptable (moderado) para categorizar terceros molares mandibulares en los residentes en formación.

Abstract Introduction: Pell & Gregory and Winter classifications are basic in third molar categorization; Sánchez-Torres classification is used in Mexico, but it has not been previously evaluated. Objective: To assess the degree of agreement in the radiographic evaluation of impacted mandibular third molar with the use of three classifications: Pell & Gregory, Winter and Sánchez-Torres. Method: Observational, descriptive, inter-observer degree of agreement study that included 10 oral and maxillofacial surgeons and 10 training residents, who recorded the radiographic categorization of third mandibular molars (left and right) according to Pell and Gregory, Sánchez-Torres and Winter classifications. Inter-observer degree of agreement was assessed with Fleiss' kappa test. Results: Pell and Gregory classification obtained the lowest degree of agreement (kappa = 0.05 and 0.185), followed by Sánchez-Torres classification (kappa = 0.125 and 0.326); Winter had the best agreement, with kappa = 0.28 and 0.636 for oral and maxillofacial surgeons and training residents, respectively. Conclusion: The Winter classification showed an acceptable (moderate) degree of agreement to classify mandibular third molars by training residents.

Is third molar agenesis an anomaly or just a sign of variation? Prevalence and manner of presentation of this condition in a sample from the Metropolitan Region of Chile / ¿Es la agenesia del tercer molar una anomalía o simplemente un signo de variación? Prevalencia y forma de presentación de esta condición en una muestra de la Región Metropolitana de Chile

Agenesis of permanent teeth is the most frequent dental anomaly. The most affected tooth is the third molar (M3), and its congenital absence poses interesting questions from a clinical and evolutionary perspective. M3 agenesis can occur isolated or as part of syndromes. Researchers have reported prevalences that vary largely among populations, between 5 % and 56 %, with a mean prevalence of 22.6 %. Previous Chilean studies, mainly in Northern populations, have determined a prevalence between 19.8 % and 26.7 %. The aim of this work was to assess the prevalence of M3 agenesis and to characterize its presentation in a sample from Santiago, the largest to date in a M3 agenesis prevalence study in Chile. In this study, 535 panoramic radiographies and clinical histories of patients from the Dental Clinic of the Universidad de Chile were used to determine prevalence and distribution according to sex, affected tooth, and location (left or right; maxilla or mandible). The Chi-square test was used to assess statistical significance in distribution. The calculated M3 agenesis prevalence was of 12.89 %. No statistically significant differences were found between sexes, sides or location within the jaws. The agenesis of one third molar was more common, then two, three and finally of all the third molars. The prevalence of M3 agenesis in the sample is 12.89 %, with a random manner of presentation. We propose that as it currently stands, M3 agenesis should be considered an anatomical variation rather than a developmental anomaly.

La agenesia de dientes definitivos es la anomalía dental más común. El diente más afectado es el tercer molar (M3), y su ausencia congénita plantea preguntas interesantes desde una perspectiva clínica y evolutiva. La agenesia de M3 puede ocurrir de manera aislada o asociada a síndromes. Estudios a nivel mundial reportan una prevalencia variable entre poblaciones: 5 % a 56 %, con una prevalencia media del 22,6 %. Estudios chilenos anteriores, principalmente en poblaciones del norte, han determinado una prevalencia entre 19,8 % y 26,7 %. El objetivo de este trabajo fue determinar la prevalencia de agenesia de M3 y caracterizar su presentación en una muestra de Santiago, la más grande hasta la fecha en un estudio de prevalencia de agenesia de M3 en Chile. Se utilizaron 535 radiografías panorámicas y antecedentes de pacientes atendidos en la Clínica Odontológica de la Universidad de Chile para evaluar la prevalencia y modo de presentación de la agenesia de M3. Se analizó su distribución según ubicación, sexo y simetría, mediante test estadístico Chi-cuadrado. Se calculó una prevalencia de agenesia de M3 de 12,89 %, sin un patrón claro ni estadísticamente significativo en su distribución. Fue más común la agenesia de un tercer molar, luego de dos, tres y finalmente de todos los terceros molares. La prevalencia de agenesia en una muestra de la Región Metropolitana es de 12,89 % y su distribución es aleatoria según la ubicación, sexo y simetría. Se propone que esta condición actualmente debiera considerarse como una variación anatómica más que a una anomalía del desarrollo.

Association between radiographic classification and surgical technique in extractions of third lower molars / Associação entre classificação radiográfica e técnica cirúrgica nas exodontias de terceiros molares inferiores

Introduction: establish an association between the radiographic classification and the surgical technique related to the lower third molars. Materials and method: a retrospective study was carried out, with the descriptive analysis of the data. The sample consisted of 100 patients (n = 100) from the spontaneous demand who sought out the Dental Clinic of UFC (Ceará's Federal University) ­ Campus Sobral, between december 2017 to july 2018, and who followed the inclusion criteria: patient with panoramic radiography, free of active periodontal disease and tooth with at least two thirds of root formation; and as exclusion criteria: patients with associated bone pathologies, teeth with less than two thirds of root formation and patients who did not wish to participate in the study. Results: patients included in the study were from 18 to 25 years of age, most of them male, with complaints of pain. Using the radiographic classification of Pell & Gregory, the most found positions were 1A (35%), 2B (28%) and 2A (17%). The most prevalent surgical techniques were the open ones. Could be done the extraction by closed surgical technique (forceps or lever) (n = 27), with flap preparation plus osteotomy (OST) (n = 25) and flap plus osteotomy plus odontostomy (ODS) (n = 48). Conclusion: teeth with radiographic classification, grade of inclusion and different preoperative plans had the same protocol (flap + OST + ODS) in the surgical act. It is evident that radiographic classification stills an effective method to aid in operative planning, but it can be complemented by other diagnostic standards, such as a specific classification of the root anatomy. (AU)

Objetivo: realizar uma associação entre a classificação radiográfica e a técnica cirúrgica relacionada aos terceiros molares inferiores. Materiais e método: foi realizado um estudo retrospectivo, com a análise descritiva dos dados. A amostra foi constituída de 100 pacientes (n = 100), provenientes de demanda espontânea, que procuraram o ambulatório de Odontologia da Universidade Federal do Ceará (UFC) ­ Campus Sobral, no período de dezembro de 2017 a julho de 2018, e que seguiram os seguintes critérios de inclusão: presença de radiografia panorâmica, ausência de doença periodontal ativa e dentes com no mínimo dois terços de formação radicular. Já os critérios de exclusão foram: pacientes com patologias ósseas associadas aos terceiros molares inferiores, dentes com menos de dois terços de formação radicular e pacientes que não desejassem participar do estudo. Resultados: os pacientes incluídos no estudo tinham idades entre 18 e 25 anos, a maioria do sexo masculino, com queixas álgicas. Em relação à classificação de Pell & Gregory, as posições mais encontradas foram 1A (35%), 2B (28%) e 2A (17%). As técnicas cirúrgicas mais prevalentes foram as abertas (73%). Em relação às técnicas cirúrgicas, foram encontradas: técnica cirúrgica fechada (fórceps ou alavanca) (n = 27), com confecção de retalho mais osteotomia (OST) (n = 25) e por retalho mais osteotomia e odontossecção (ODS) (n = 48). Conclusão: é evidente que a classificação radiográfica ainda é um método eficaz para auxiliar no planejamento operatório, mas pode ser complementada por outros padrões de diagnóstico, como uma classificação específica da anatomia radicular. (AU)

Evaluation of demographic and radiological risk factors for assessment of difficulty in surgical removal of impacted mandibular third molar: a prospective study

The extraction of impacted third molars is among the most common surgical procedures carried out in the field of Oral and Maxillofacial Surgery. Both the patient and dentist must therefore have scientific evidence-based information concerning the estimated level of surgical difficulty of every case to consider in referring cases of impacted third molars for specialists' handling. We have undertaken a study in which demographic and radiological variables were considered to-gether to evaluate the risk factors for surgical difficulty in a cohort of 100 impacted mandibular third molars. There were 13 variables evaluated for surgical difficulty. Total surgical time interven-tion was noted at the end of each surgery. Each variable was analysed with total surgical time intervention with univariate and multiple linear regression. Out of 13 variables, 9 were found sta-tistically significant. The most significant predictors for surgical difficulty were Body Mass Index, Depth of impacted tooth and Retromolar space. No postoperative complications were reported.

Inward fragmentation and socket preservation in complex mandibular third molar surgery - a case report

Open extraction sockets following inward fragmentation of partially erupted mandibular third molars may compromise the hard tissue regeneration and lead to postoperative complications. in the case report, we present socket preservation to seal the open alveolous without flap displacement. a female patient aged 22, presented for removal of a partially erupted M3M was operated on via occlusal inward fragmentation under magnifying endoscopic vision. critical nerve structures were identified and protected before socket preservation with resorbable in situ hardening TCP particles was performed. the alveolar bone site healed uneventful, panoramic and cross-sectional conebeam reformats confirmed an complete hard tissue maintanence. endoscopically assisted inward fragmentation combined with socket preservation leads to the maintenance of adjacent hard tissues without need for flap transposition in complex anatomical sites.

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.

Age prediction in the adult based on the pulp-to-tooth ratio in lower third molars: a cone-beam CT study / Predicción de edad en el adulto basada en la proporción pulpa-a-diente en terceros molares inferiores: un estudio por TC de haz de cono

Estimation of age-at-death is an integral part of the identification process of individuals in many forensic odontology cases where their identity cannot be determined by visualization or other ways. Dental age estimation in the adult is more challenging as most of the dentition is completely developed by 18 years of age. This study employs a mesio-distal (MD) pulp-to-tooth ratio taken at the neck of lower third molars (LM3) to provide an estimation of age at the time of radiographic imaging based on the well-known fact that pulp volume tends to decrease with advancing age due to continued apposition of secondary dentine throughout adulthood. A total of 155 Cone-beam computed tomography (CBCT) radiographs of LM3s for a random sample of 155 Jordanian Arabs (80 females, 75 males; age range= 18-58 years, mean age= 28.2 years, SD =10.0 years) were used. Both pulp and tooth MD diameters were measured at the neck. MD pulp-to-tooth ratios for LM3s were linearly regressed against age. Statistically significant negative association was found between an individual's age at the time of imaging and the MD pulp-to-tooth ratio taken at the neck. Specifically, the strength of the association is r= -0.361, which means only 13.0 % of the variation in age can be explained by the MD pulp-to-tooth ratio taken at the neck. Therefore, it was concluded that MD pulp-to-tooth ratio taken at the neck of LM3s is not a reliable predictor of chronological age in adults, possibly due to the large variation in the timing of LM3 development.

La estimación de la edad es una parte integral del proceso de identificación de los individuos, en muchos casos en odontología forense donde la identidad no puede ser determinada por visualización u otras formas. La estimación de la edad dental en el adulto es aún más difícil ya que la mayor parte de la dentición se desarrolla completamente a los 18 años de edad. Este estudio emplea una relación mesio-distal (MD) de pulpa a diente tomada a nivel del cuello de los terceros molares inferiores (LM3) para proporcionar una estimación de la edad en el momento de la imagen radiográfica basada en que el volumen de pulpa tiende a disminuir con el avance de la edad debido a la continua posición de la dentina secundaria a lo largo de la edad adulta. Se examinaron un total de 155 radiografías de LM3 en una muestra aleatoria de 155 árabes jordanos (80 mujeres, 75 varones), rango de edad = 18-58 años, edad media = 28,2 años, DE = 10,0 años. Específicamente, la fuerza de la asociación es r=0,361, lo que significa que sólo el 13,0 % de la variación en la edad puede explicarse por la proporción pulpa-a-diente.

Evaluation of 1211 third molars positions according to the Classification of Winter, Pell & Gregory / Evaluación de posiciones de 1211 terceros molares acorde a la Clasificación de Winter, Pell & Gregory

Panoramic radiographs are important for the evaluation and classification of the third molars position, allowing the diagnosis and planning of extraction. The objective of this study is to evaluate upper and lower third molars positions in panoramic radiographs with the classification methods proposed by Pell and Gregory (1933) and Winter (1926) and the subsequent comparison of results with other authors. Panoramic radiographs of 310 patients were analyzed, 197 female and 113 male, totaling 1,211 third molars. In relation to the upper third molars, the most prevalent positions were: angle compared to the long axis of the second molar of Distoangular form (53.23 %) and the depth of impaction as Class C (48.25 %). In the lower third molars, the most prevalent positions were: angle to the long axis of the second molar in Mesioangular classification (52.96 %), the depth of impaction was B (46.54 %) and the tooth relationship with the mandibular ramus was identified as class I (55.26 %). These results provide information that can be utilized in predicting third molar development in terms of impaction or eruption, assisting dental surgeons in making decisions regarding surgical planning and treatment.

Las radiografías panorámicas son importantes para la evaluación y clasificación de la posición de los terceros molares, lo que permite el diagnóstico y la planificación de la extracción. El objetivo de este estudio fue evaluar terceros molares superiores e inferiores y posiciones en las radiografías panorámicas con los métodos de clasificación propuestas por Pell & Gregory, y Winter y la posterior comparación de los resultados con otros autores. Se analizaron las radiografías panorámicas de 310 pacientes, 197 mujeres y 113 hombres, con un total de 1.211 terceros molares. En relación con los terceros molares superiores, las posiciones más prevalentes fueron: ángulo con respecto al eje longitudinal del segundo molar de forma distoangular (53,23 %) y la profundidad de la impactación como Clase C (48,25 %). En los terceros molares inferiores, las posiciones más prevalentes fueron: ángulo con respecto al eje longitudinal del segundo molar en la clasificación mesioangular (52,96 %), la profundidad de impactación fue de B (46,54 %) y la relación de los dientes con la rama mandibular fue identificado como Clase I (55,26 %). Estos resultados proporcionan información que puede ser utilizada para predecir el desarrollo del tercer molar en términos de compactación o erupción, ayudando a los cirujanos dentistas en la toma de decisiones respecto a la planificación y el tratamiento quirúrgico.