Association of indications for mandibular third molar coronectomy and the Pell and Gregory and the Winter classification systems.

PURPOSE: The purpose of this study was to determine how the surgeon's decision to perform a mandibular third molar coronectomy or surgical removal is associated with the impaction pattern as classified using Pell and Gregory or Winter's system. METHODS: This observational, cross-sectional study was conducted on 813 mandibular third molars belonging to 565 patients. All patients were referred for removal of the mandibular third molar and had radiographic signs indicating a close relationship with the inferior alveolar nerve. Panoramic images were classified according to the impaction pattern. RESULTS: A coronectomy was performed on 492 (60.5%) mandibular third molars. Most impacted mandibular third molars were class IIB with a mesioangular inclination. A significant association was found between the Pell and Gregory classification and the surgeon's choice (p = 0.002). Winter's classification was not significantly associated with surgeon choice (p = 0.425). CONCLUSION: Mandibular third molar coronectomy is chosen more frequently than surgical removal if molars are class III and position B. TRIAL REGISTRATION NUMBER: Not applicable.

Radiographic Evaluation of Impacted Third Mandibular Molar According to the Classification of Winter, Pell and Gregory in a Sample of Cameroonian Population.

Background: The extraction of impacted third molars (M3) is a common surgical procedure in dentistry and oral surgery. Various complications, including inferior alveolar nerve (IAN) damage, may occur during and after extraction of this tooth. Radiographic examination should provide information about the M3 itself, but also about the surrounding bony structure and the relationship of the roots to the IAN and the adjacent second molar, which is often traumatized during this extraction. The aim of our study was to evaluate the depth and angulation of impacted mandibular third molars (M3) from panoramic radiographs, according to the classifications proposed by Winter and Pell & Gregory. Methods: Radiographic signs present on the orthopantomogram showing M3 depth, and retromandibular available space according to the Pell & Gregory classification were evaluated. Evaluation of the M3 angulation relative to the M2 according to Winter's classification was also done. Student's t test was used to determine the association between side or sex and different variables. Results: The depth of impaction of the M3 crown was level A accounting for 54.4% (n=260) of the PR while level B constituted 35.7% (n=171) of the images. Regarding the availability of retromandibular space, Class I constituted 36.8% (n=176). The Class II accounted for 55.9% (n=267) of PR. Conclusion: Our study showed that 54.4% of M3 were located at the same level as the occlusal plane of the second molar, while in 56% of PR the space between the second molar and the ramus of the mandible is less than the mesiodistal diameter of the third molar. This research showed that 23.1% of M3 had a level of vertical angulation, a level that allows for less painful luxation of the impacted molars. These results seem to show a relatively high level of difficulty in mobilizing and extracting M3 from Cameroonian patients.

Agreement analysis of three mandibular third molar retention classifications.

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.

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.

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.

Evaluation of the relationship between gonial angle and impacted mandibular third molar teeth.

Mandibular third molar teeth have the highest impaction frequency for several reasons such as lack of space which may be related to the direction of facial growth. Gonial angle is used for the definition of facial growth pattern with some other measures such as mandibular plane angle. Winter and Pell-Gregory classifications are used for defining the level and pattern of mandibular third molar impaction. The aim of this study is to define the relationship between mandibular third molar impaction pattern and gonial angle; also to evaluate relationship between mandibular third molar roots and inferior alveolar canal. Study included 90 patients who had undergone cone beam computed tomography assessment for mandibular third molar impaction. Impacted teeth were grouped according to Pell-Gregory depth (A, B, C) and ramus (1, 2, 3) classification and sub-groups were composed. Winter classification was used for angulation of third molars and their relationship between with inferior alveolar canal was recorded. Gonial angle was measured on panoramic radiographs. Of the evaluated 90 impacted third molars, mesioangular position was the most frequent (34.4%), followed by vertical, horizontal and distoangular positions. Nearly 77% of the impacted third molar roots were related to inferior alveolar canal. While no correlation was determined between gender, age, third molar angulation and gonial angle, C2 sub-group of Pell-Gregory classification showed statistically significant higher gonial angle values. Although no significance was found, gonial angle was higher in level C group. In conclusion, gonial angle is higher in patients with C2 impaction level. Also, although statistically insignificant, Pell-Gregory C group had higher gonial angle averages.

Three-dimensional position of impacted maxillary canines: Prevalence, associated pathology and introduction to a new classification system.

Classification of impacted maxillary canines facilitates interdisciplinary communication. Cone beam computed tomography (CBCT) has proven to be superior for the localization of impacted maxillary canines compared with 2D imaging. The purpose of this study was to retrospectively classify a cohort of impacted maxillary canines, using a new developed 3D classification for impacted maxillary canines that is easy to use and does not require complex analysis of the 3D images. A retrospective cohort study was designed, containing CBCT data of 130 patients (male/female: 48/82; median age 16) with a total of 162 impacted maxillary canines. The proposed classification was based on four criteria: vertical crown position, mesiodistal tooth postion, bucco-lingual crown position, and associated pathology. For all included patients, classification criteria were identified and correlated to treatment selection using a newly developed 3D classification. The most common positions were vertical crown position at apical one third of neighboring teeth, mesiodistal tooth angulation, and palatal crown position. The most frequent associated pathologies were dilaceration of the root and resorption of a neighboring tooth. Significant associations among classification variables and treatment options were observed. Limitations of this study are the retrospective design. CBCT enabled 3D assessment of impacted maxillary canines allowing a classification system that may have an impact on further treatment strategies.

Cone beam computed tomography review and classification of mesiodens: Report of a case in the nasal fossa and nasal septum.

Supernumerary teeth are an uncommon occurrence that have the ability to arise anywhere in the dental arch. Mesiodens is a specific type of supernumerary tooth that occurs in the vicinity of the maxillary central incisors. Mesiodens are the most common among all supernumerary teeth, almost always impacted, and may also be seen in various positions based on the eruption status. The formation of mesiodens is a much-debated topic and many theories have been proposed. The reports also include its common radiographic findings and a pertinent literature review. This study reports a case of an impacted, inverted mesiodens incidentally discovered on a preimplant examination of maxilla. This article demonstrates the scope of eruption of an impacted and inverted mesiodens. Various methods of treatment plan are discussed and a new classification system of mesiodens is proposed.

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.

Retenção prolongada de dente decíduo por impactação de dente supranumerário em criança de 12 anos / Tooth prolonged retention of deciduous tooth impaction supernumerary in children under 12 years

Dente supranumerário é definido como um distúrbio de desenvolvimento caracterizado pela presença de um ou mais elementos dentários fora do número considerado normal de uma arcada. A ocorrência dos supranumerários pode ocasionar uma variedade de complicações, como por exemplo, apinhamento de dentes permanentes, erupção retardada e/ou ectópica, rotação dentária, formação de diastema, desenvolvimento de lesões císticas, reabsorção de dentes adjacentes. Na maioria das vezes o diagnóstico da presença desse elemento é realizado por exame clínico e radiográfico de rotina. O objetivo do presente trabalho foi relatar um caso clínico de retenção prolongada de um dente decíduo e erupção retardada de um dente permanente em decorrência da presença de um elemento supranumerário diagnosticado apenas aos 12 anos de idade. Após a identificação do elemento supranumerário e análise de exames radiográficos complementares,foi realizada cirurgia para remoção dos elementos decíduo e supranumerário, bem como acompanhamento por três meses do processo eruptivo do elemento impactado,um segundo pré-molar inferior direito o qual se posicionou favoravelmente na arcada dentária. Concluiu-se que a detecção em momento oportuno e a remoção de elementos supranumerários, também respeitadas à necessidade e oportunidade cirúrgica, são importantes para evitar danos futuros à oclusão dos pacientes, devendo-se dar importância ao acompanhamento e evolução clínica do caso.

Supernumerary teeth is defined as a developmental disorder characterized by the presence of one or more dental elements out of a number considered normal arch. The occurrence of supernumerary can cause a variety of complications, such as crowding of the permanent teeth,delayed and / or ectopically erupting, tooth rotation, diastema training, development of cysticlesions, resorption of adjacent teeth. In most cases the diagnosis of the presence of this elementis made by clinical examination and routine radiographic. The aim of this study was to reporta case of prolonged retention of a primary tooth eruption and delayed a permanent tooth dueto the presence of a supernumerary element diagnosed only 12 years old. After identifying the supernumerary element and analysis of complementary radiographs, it was carried out surgeryto remove the elements deciduous and supernumerary and monitoring for 3 months of the eruptive process impacted element, a premolar law that favorably-positioned in the dental arch.It was concluded that the timely detection and removal of supernumerary elements also respected the need and surgical opportunity, are important to prevent future damage to the occlusion of patients, should be given importance to the monitoring and clinical outcome.

Concomitant Third Molar Removal During Sagittal Split Osteotomy of the Mandible.

It is described in textbook about management of third molar in orthognathic surgery that "ideally, the third molars should be removed 9 to 12 months before sagittal split osteotomy (SSO)." At the Chang Gung Craniofacial Center, the authors always remove mandibular third molars during SSO, because: removal of third molars at the same time of SSO could reduce psychological stress on patients by saving 1 surgical procedure under local anesthesia, better exposure of impacted third molars could be facilitated by sagittal split of buccal cortical plate, rigid fixation could be performed without difficulty by our fixation method using plates and screws crossover anterior oblique line. Strong force during the elevation of third molars, however, may result in the fracture of distal segment of SSO, where the buccal cortical plate is relatively thin because of the presence of third molar. Therefore, more care needs to be taken in the surgical technique, which is different from ordinary tooth extraction. In this paper, the details of surgical procedure of third molar removal during SSO were reported.

What Are the Types and Frequencies of Complications Associated With Mandibular Third Molar Coronectomy? A Follow-Up Study.

PURPOSE: Coronectomy has been proposed for impacted third molars in close proximity to the inferior alveolar nerve (IAN) to avoid neurologic injury. Immediate (up to 1 month) and late (2 to 36 months) postoperative complications were investigated. MATERIALS AND METHODS: A prospective cohort study was performed on healthy patients treated in the dental clinic of the Department of Oral Surgery, University of Bologna. The predictor variables examined were experience of the surgeon (<10 vs ≥10 yr), length of surgery, type of mandibular third molar inclusion, and patient age. To assess the rate of postoperative complications, outcome variables were neurologic injuries, postoperative pain, swelling, fever, alveolitis, pulpitis, and root exposure. The success rate and need for a second surgery also were investigated. Univariate and bivariate descriptive statistics, Kaplan-Meier analysis, and Cox hazards modeling were performed to evaluate the variables. RESULTS: The study involved 94 healthy patients (mean age, 28.99 ± 8.9 yr; range, 17 to 56 yr; 37 men and 57 women) who had 116 third mandibular molars treated with coronectomy. During the 3-year follow-up period, 28 patients (29 coronectomy procedures) dropped out of the study. There was no case of neurologic injury to the inferior alveolar nerve (IAN) or to the lingual nerve (LN). In total, 30 complications were observed (25 within 1 month; 5 at 2 to 12 months). Surgeons with less than 10 years of training exposed patients to a greater risk of complications (hazard ratio = 2.069; 95% confidence interval, 1.004-4.263). An overall success rate of 74% at 6 months was estimated, and a second surgery was needed in 6% of cases. Of the retained roots analyzed, 80% showed postoperative root migration. CONCLUSIONS: In this study, coronectomy of mandibular third molars did not result in temporary or permanent injury to the IAN or LN. Coronectomy showed a low rate of postoperative complications. However, within the first year, a second surgery was needed in 6% of coronectomy procedures to remove migrated root fragments. Additional studies with larger patient samples are recommended to further investigate differences in postoperative complications in relation to patient age.

Simultaneous Removal of Third Molars During a Sagittal Split Does Not Increase the Incidence of Bad Splits in Patients Aged 30 Years or Older.

PURPOSE: An increasing number of patients who are 30 years old or older have been presenting for orthognathic surgery, some of whom have impacted third molars. The purpose of our report was to review the incidence of bad splits in this age group, both with and without third molars (3Ms). MATERIALS AND METHODS: A retrospective cohort analysis of all patients who had undergone sagittal split osteotomy (SSO) who were 30 years old or older was performed. The inclusion criteria were age 30 years or older and performance of an SSO. Those with incomplete data or who were younger than 30 years old were excluded. A history and radiographic review was performed to find cases with a bad split that had occurred during the surgical procedures. The fractures were correlated with the presence or absence of the lower 3Ms, the degree of impaction of the 3Ms, and patient age and gender. For this aged sample, the variables of 3M presence and gender were analyzed using the Fisher exact test. For patient age, analysis of variance was applied, and for the degree of impaction, the Pearson test was used. All the tests used the level significance of 0.05%. RESULTS: Of the 220 patients who underwent SSO during the study period, 52 were older than 30 years (24%). Of these, 8 patients (15%) had had at least 1 3M present at surgery. Most of the patients had undergone sagittal splits without complications. A total of 3 patients had had bad splits in this sample, 1 of whom had a 3M present at surgery and 2 of whom did not. No association was found between the occurrence of a bad split and the variables studied, including the presence of a 3M (P = .089), degree of impaction (P = .074), age (P = .963), and gender (P = .266). CONCLUSIONS: From the results in this small subset of patients, 3Ms can be removed in patients older than 30 years concomitant with bilateral SSO.

A simple score for evaluation of the complexity of third-molar extractions.

OBJECTIVES: This article proposes a simple preoperative score to evaluate the complexity of tooth extractions of the third mandibular molar and to estimate the time involved. STUDY DESIGN: We consider 11 factors (demographic, anatomic, and radiologic) that favor the surgery and that can be identified through standard clinical and radiologic examinations. The number of favorable factors (NFF) relative to each patient constitutes his/her score. The analysis of 1500 extractions performed by various surgeons with experience from 2 to 25 years evidences a quadratic inverse correlation between NFF and the time required for the surgery. RESULTS: The shape of the time distribution suggests the existence of 3 major classes of patients characterized by time of 4 to 10 minutes, 11 to 20 minutes, and 21 to 40 minutes. The corresponding NFF brackets, as identified by their frequency distributions and validated by the receiver operating characteristic curve method, are 5 to 11 (mean [SD], 6.8 [1.6]), 2 to 4 (3.3 [1.3]), and 0 to 1 (0.8 [1.0]), respectively. CONCLUSIONS: Our results show the good performance of this score as a predictor of the surgical time and its applicability in daily practice regardless of operator experience, background, and level of surgical ability.

Root morphology and development of labial inversely impacted maxillary central incisors in the mixed dentition: a retrospective cone-beam computed tomography study.

INTRODUCTION: The aim of this study was to analyze 3-dimensional data of root morphology and development in labial inversely impacted maxillary central incisors. METHODS: Cone-beam computed tomography images from 41 patients with impacted incisors were divided into early and late dental age groups according to their dental age. Sagittal slices in which the labiolingual width of the tooth was the widest in the axial view were evaluated. The inverse angle, the dilaceration angle, and the length of both impacted and homonym teeth were evaluated with SimPlant Pro software (version 13.0; Materialise Dental NV, Leuven, Belgium). RESULTS: The Student t test indicated that the lengths of the impacted teeth were significantly shorter than those of the homonym teeth (P <0.05), and the root lengths of the early dental age group were significantly shorter than those of the late dental age group. The results from chi-square tests indicated that the incidence of dilacerations was significantly higher in the late dental age group when compared with the early dental age group. Multiple regression analyses indicated that the independent variables for root length of the impacted teeth were dental age (ß = 0.958; P <0.001) and length of the nondilacerated part of the root (ß = 0.435; P <0.001). CONCLUSIONS: Dilaceration was more common in the late dental age group. The roots of labial inversely impacted maxillary central incisors continue developing, but their potential is limited.

The most common complications after wisdom-tooth removal: part 1: a retrospective study of 1,199 cases in the mandible.

The knowledge of potential complications after surgical removal of third molars and adequate risk assessment is indispensable in oral surgery. The present retrospective study analyzed the influence of different parameters, such as the patient’s age and gender, retention type, and radiological projection (using orthopantomography) of wisdom teeth on the mandibular canal on postoperative complications after the removal of 1,199 wisdom teeth. Overall, 101 (8.4%) complications occurred: 50 cases of alveolar osteitis (4.2%), 12 temporary (1%) and 6 persistent (0.5%) sensation disorders, 15 abscesses (1.25%), 7 dehiscences (0.6%), 5 cases of post-operative bleeding (0.4%), 4 sequestra (0.32%), 1 fistula (0.08%) and 1 hematoma (0.08%). The risk for developing alveolar osteitis was 6% for patients who suffered from a previous pericoronal infection and was higher for female than male patients. Smoking showed no influence on alveolar osteitis. A significant correlation (p<0.0001) could be shown between the radiological projection of wisdom teeth on the mandibular canal and post-operative sensation disorders. The experience of the surgeon and pre-operative 3-dimensional imaging (cone- beam computed tomography, computed tomography) did not reduce this risk. No correlation was found for patient’s age and gender. In conclusion, the surgical decision to remove wisdom teeth must be made with caution in cases of complete radiological projection of the wisdom tooth on the mandibular canal.

The most common complications after wisdom-tooth removal: part 2: a retrospective study of 1,562 cases in the maxilla.

The possible complications of wisdom-tooth removal must be considered, because it is the most common surgical intervention in dental practices. This retrospective study assessed the complications occurring during the removal of 1,562 maxillary wisdom teeth in 1,212 patients. A total of 543 cases of surgical removal and 1,019 cases of non-surgical removal were analyzed. In all cases, a pre-operative panoramic radiograph was taken. Anatomical and clinical parameters were included in the evaluation. 106 complications occurred in 92 patients (5.9%) of the total 1,562 operations. Of these complications, 5.1% were intra-operative and 0.8% postoperative. An oroantral fistula (OAF) was found in 38 cases (2.4%), and alveolar osteitis occurred post-operatively in 6 cases (0.4%). The risk of OAF correlated with increasing patient age (p=0.0368). Root fractures also increased the risk of OAF. On the basis of the analysis of pre-operative panoramic radiographs, it was shown that radiological projection of the root tips to the sinus floor is a reliable criterion to assess the risk of OAF.

Permanent mandibular canine(s) impaction: expansion of our understanding.

INTRODUCTION: Eruption disturbances, tooth size and specific malocclusions are known to be genetically influenced. The clinical association between these traits may indicate common genetic controls. OBJECTIVES: A cross-sectional clinical study was designed to test the null hypothesis that the maximum mesiodistal crown diameter (MMD) of maxillary and mandibular central and lateral incisors and the prevalence of various classes of incisor relationships (Class I, II/1, II/2 and III) do not differ between the subjects with and without permanent mandibular canine(s) impaction. METHODS: Dental models of 43 subjects diagnosed with mandibular canine(s) impaction (Impaction Group - IG) were compared with those of 86 subjects of a control reference sample (Control Group - CG). Independent t-test and chi-square tests were used to determine the association between mandibular canine(s) impaction and the MMD of the incisors and the incisor relationship, respectively. The likelihood of various incisor relationships between the IG and CG were evaluated according to odds ratios. RESULTS: A fourfold increase (p < 0.0001) in the overall frequency of Class II/2 incisor relationship was observed in the IG when compared to controls. CONCLUSIONS: The null hypothesis was rejected. Subjects with mandibular canine(s) impaction appeared to be characterised with wider incisors and a remarkably high rate of Class II/2 malocclusion. This information assists the understanding of genetically controlled dental anomalies, which are likely to coexist with mandibular canine(s) impaction.

Panoramic radiography and cone-beam computed tomography findings in preoperative examination of impacted mandibular third molars.

BACKGROUND: Preoperative radiographic examination of impacted mandibular third molars (IMTM) is essential to prevent inferior alveolar nerve injury during extraction. The purpose of this study was to evaluate the correlation between cone-beam computed tomography (CBCT) and digital panoramic radiography (DPR) findings in preoperative examination of IMTM. METHODS: This retrospective study included 298 teeth in 191 individuals. The relationship between the inferior alveolar canal (IAC) and the IMTM (buccal, lingual, interradicular or inferior), the position of the IMTM with respect to the IAC (contact, no contact), the morphologic shape of the mandible in the IMTM region (round, lingual extended, lingual concave), the type of IMTM (vertical, horizontal or angular) and the number of roots of the IMTM were evaluated on CBCT images. DPR images were evaluated for the number of roots of the IMTM and for the most common radiographic findings indicating a relationship between the IAC and the IMTM (darkening of the roots, diversion of the IAC, narrowing of the IAC and interruption of the white line). Data were statistically analyzed with Cramer V coefficient, Kappa statistic, chi-square and Fisher's exact test. RESULTS: There was a significant difference in number of roots detected on DPR versus CBCT images. There was a significant association between the type of IMTM and the morphologic shape of the mandible on CBCT images. Darkening of the roots and interruption of the white line on DPR images were significantly associated with the presence of contact between the IMTM and the IAC on CBCT images. CONCLUSIONS: Panoramic radiography is inadequate, whereas CBCT is useful to detect multiple roots of IMTM. When darkening of the roots and interruption of the white line are observed on panoramic images, there is increased likelihood of contact between the IMTM and the IAC. CBCT is required in these cases.

[Terminology and manifestations of eruption disturbances]. / Terminologie en vormen van eruptiestoornissen.

Eruption disturbances of teeth are not unusual; many variations are encountered and eruption disturbances can negatively influence the development of the tooth and jaw system. Causes of eruption disturbances can be categorized into general and local factors. The clinical spectrum of eruption disturbances involves syndromic and non-syndromic problems for both kinds of factors, varying from delayed eruption to primary failure of eruption. The following types of eruption disturbances should be distinguished: impaction, primary retention, secondary retention and primary failure of eruption. Early detection of eruption disturbances and timely and appropriate treatment of the various eruption disturbances play an important role in preventing the negative effects of eruption disturbances on the development of the dentition and the craniofacial skeleton.

Variations in the anatomical positioning of impacted mandibular wisdom teeth and their practical implications.

Surgical removal of impacted third molars is one of the most frequent procedures in oral surgery. Here, three-dimensional (3D) imaging is often used, yet its necessity is still being heavily debated. The aim of the study was to describe the variation in the anatomical positioning of third mandibular molars, and, by doing so, examine the necessity of 3D imaging. A retrospective case study was performed with the patients from an oral surgery department from January 2009 to February 2013. The primary focus of the study was on the spatial relationship to the mandibular canal, as well as angulation, root configuration, and developmental stage of the wisdom tooth. Descriptive statistics were calculated for these variables. A total of 1197 wisdom teeth in 699 patients were evaluated. 46.7% exhibited direct contact to the mandibular canal, another 28.7% showed close proximity and 24.6% a measurable distance. In 29.0%, the mandibular canal was vestibular and in 23.8% lingual to the wisdom tooth. In 7.4%, it was interradicular and in 0.6% intraradicular. Most teeth had one (21.3%) or two (55.3%) roots. Others had three (17.6%), four (2.0%) or five (0.2%) roots. In 31.4% of the teeth, the root perforated the lingual compact bone, and in 4.3% the vestibular compact bone. 44.4% of the teeth had mesial angulation, 9.7% distal angulation, 35.3% lingual and 2.9% buccal angulation. Due to the anatomical variety, the use of 3D imaging is recommended before surgical removal of mandibular third molars if conventional imaging cannot exclude complicated conditions.