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.

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.

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.

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.

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.

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.

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.

[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.

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.

Effect of menstrual cycle on frequency of alveolar osteitis in women undergoing surgical removal of mandibular third molar: a single-blind randomized clinical trial.

PURPOSE: To measure the association between the menstrual cycle and the frequency of alveolar osteitis (AO). MATERIALS AND METHODS: In a study with a single-blind design, patients with bilateral impacted third molar teeth underwent randomized surgical extraction: one tooth during the menstrual period and one during the middle of the cycle. The postoperative examiner was unaware of the menstrual cycle status of the patients. The predictor variable was the timing of the menstrual cycle and was grouped as mid-cycle and menstrual period. The outcome variable was AO, which was measured (without knowledge of the menstrual cycle timing) at 2 to 7 days postoperatively. Other study variables included oral contraceptive (OC) use, smoking status, irrigation used during surgery, extraction difficulty, surgeon experience, number of local anesthetic cartridges used, and patient age. Appropriate bi- and multivariate statistics were computed, and the level of statistical significance was set at P < .05. RESULTS: A total of 145 female patients, with a mean age of 24 years, underwent 290 third molar extractions. The overall frequency of AO was 23.45%. The frequency of AO was significantly greater in the middle of the cycle than during the menstrual period inboth the OC users and nonusers (P < .05). Although OC users revealed a significantly greater frequency of AO compared with nonusers (P < .05), no statistically significant differences were found between the 2 groups during the menstrual period (P > .05). CONCLUSIONS: According to the results of the present study, the menstrual cycle could be a determinant risk factor in the frequency of AO. We recommend that elective procedures be performed during the menstrual period in both OC users and nonusers to eliminate the effect of cycle-related hormonal changes on the development of AO.

Assessment of factors associated with surgical difficulty during removal of impacted maxillary third molars.

PURPOSE: Estimating the difficulty of removing third molars is a common dilemma. However, the estimation of the difficulty associated with maxillary third molar surgery has not yet been defined. The aim of the present study was to determine the degree of difficulty and identify predictor variables associated with the occurrence of difficulty in the removal of impacted maxillary third molars. MATERIALS AND METHODS: A prospective cohort study was carried out involving patients who underwent at least 1 surgical removal of an impacted maxillary third molar at the Oral and Maxillofacial Surgery Unit, University of Pernambuco (Pernambuco, Brazil). Predictor variables indicative of surgical difficulty were classified by their demographic, clinical, and radiographic aspects. Degree of surgical difficulty was categorized as low, moderate, or high based on the surgical technique used. Descriptive and bivariate statistics were computed. RESULTS: In total, 106 patients fulfilled the eligibility criteria and 204 surgeries were performed. Patients' mean age was 22.8 ± 2.2 years and the proportion of women to men was 3:1. Approximately 20% of patients were overweight. Surgical difficulty was generally low and 5 variables were significantly associated with the occurrence of a high degree of surgical difficulty. CONCLUSION: Surgical difficulty during the removal of impacted maxillary third molars is generally low. However, for cases with a high degree of difficulty, identification of predictor variables may be useful for students and inexperienced clinicians to consider the decision not to execute the procedure, thus avoiding complications that often require complex management.

Reliability of a novel CBCT-based 3D classification system for maxillary canine impactions in orthodontics: the KPG index.

The aim of this study was to evaluate both intra- and interoperator reliability of a radiological three-dimensional classification system (KPG index) for the assessment of degree of difficulty for orthodontic treatment of maxillary canine impactions. Cone beam computed tomography (CBCT) scans of fifty impacted canines, obtained using three different scanners (NewTom, Kodak, and Planmeca), were classified using the KPG index by three independent orthodontists. Measurements were repeated one month later. Based on these two sessions, several recommendations on KPG Index scoring were elaborated. After a joint calibration session, these recommendations were explained to nine orthodontists and the two measurement sessions were repeated. There was a moderate intrarater agreement in the precalibration measurement sessions. After the calibration session, both intra- and interrater agreement were almost perfect. Indexes assessed with Kodak Dental Imaging 3D module software showed a better reliability in z-axis values, whereas indexes assessed with Planmeca Romexis software showed a better reliability in x- and y-axis values. No differences were found between the CBCT scanners used. Taken together, these findings indicate that the application of the instructions elaborated during this study improved KPG index reliability, which was nevertheless variously influenced by the use of different software for images evaluation.

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.

Pre-treatment radiographic features predict root resorption of treated impacted maxillary central incisors.

OBJECTIVES: To determine independent predictors of root resorption for surgical-orthodontic treatment of impacted maxillary central incisors. SETTING AND SAMPLE POPULATION: The Department of Dentistry at Show Chwan Hospital, Changhua, Taiwan. Eighty patients with unilateral osseous-impacted maxillary central incisors receiving a surgical-orthodontic treatment. MATERIAL AND METHODS: This is a retrospective observational study. Root resorption and its predictors were abstracted from patients' charts, pre-treatment cephalometric radiographs, and post-treatment periapical radiographs. Predictors included demographics, treatment duration, crown angle, crown height, crown depth, and root dilacerations. RESULTS: The patients' mean age was 9.2 ± 2.3 years (6.4-20.6 years), and 60% were females. Impacted maxillary central incisors had greater root resorption than naturally erupted contralateral incisors (Δ = -2.8 mm, p < 0.001). Independent predictors of root resorption for impacted maxillary central incisors were shown by linear regression analysis to be crown height (ß = -0.2, p < 0.01), crown depth (ß = -0.3, p = 0.001), treatment duration (ß = 0.2, p < 0.01), and root dilacerations (ß = 3.1, p = 0.001). CONCLUSIONS: Impacted maxillary central incisors had greater root resorption during surgical-orthodontic treatment than their naturally erupted contralateral incisors. Predictors of a greater root resorption were highly and deeply impacted incisors, longer treatment, and root dilacerations. These predictors may help to inform patient and family counseling before treatment.

Surveillance as a management strategy for retained third molars: is it desirable?

The purpose of the present report was to define and advocate active surveillance compared with follow-up as needed (prn follow-up), as the preferred management strategy for patients who elect to retain their third molars (M3s). Active surveillance, a nonoperative management strategy for retained M3s, is characterized as a prescribed, regularly scheduled set of follow-up visits that include both clinical and radiographic examinations. Given that the risk of complications with M3 removal are age related, the rationale for recommending active surveillance instead of "prn follow-up" is that the frequency of future disease among retained M3s is sufficiently high to warrant routine scheduled follow-up visits to detect and treat disease before it becomes symptomatic. Symptomatic disease is a late finding. Patients electing active surveillance as their preferred management strategy might not avoid operative treatment in the future, but it should increase their chances of being diagnosed at the youngest age possible, thus minimizing the age-related operative complications. The author recommends that the frequency of follow-up visits be approximately every 24 months and the examination be completed by a specialist or general dentist. Active surveillance as a management strategy is based on level 5 evidence (ie, expert opinion).

How often do asymptomatic, disease-free third molars need to be removed?

The preventive removal of third molars (M3s) should be based on evidence. To optimize the timing of removal of M3s, it is essential to predict the eruption of the tooth and, even more importantly, to recognize beforehand which teeth will become involved in pathologic conditions later in life. The first aim of this review was to determine how well physicians currently can predict the eruption of an M3. The second aim was to review how frequently impacted M3s are removed. The third aim was to summarize the indications for preventive removals as presented in the evidence-based Current Care Guideline for the management of M3s in Finland. The prediction of eruption can be made at accuracies from 80% to 97%. In addition, the decrease in the number of M3s is very rapid, with only 31% remaining at 38 years of age. According to the Current Care Guideline, preventive removals at a young age are justified for 3 groups of teeth in the mandible: partially impacted teeth in the horizontal position, partially erupted teeth in the vertical position, and incomplete roots growing close to the mandibular canal. In conclusion, one fourth of retained and disease-free M3s need to be removed preventively at a young age, whereas the rest should be treated according to signs and symptoms.

How many patients have third molars and how many have one or more asymptomatic, disease-free third molars?

The purpose of this report was to summarize the frequencies of third molars (M3s) in general and asymptomatic, disease-free M3s specifically. Estimates of M3 prevalence range so widely (ie, 6.0% to 96%) as to be of little use. The estimates vary depending on definitions, age, clinical versus radiographic assessment, and patient versus population samples. For patient management, it may be more valuable to estimate the prevalence of M3s grouped by clinical rather than anatomic status. Many times, however, M3s are categorized simply as asymptomatic. In many pathologic processes, from cancer to cardiovascular disease, the term asymptomatic does not equal an absence of disease. As such, M3s should be categorized based on symptom and disease status. Subjects with all M3s asymptomatic and absent of disease ranged from 12% in a sample of patients referred for M3 evaluation to 29% in a nonpatient volunteer sample. In the patient sample, 37% of the M3s evaluated were asymptomatic and free of disease.

Maxillary third molar: patterns of impaction and their relation to oroantral perforation.

PURPOSE: The objectives of this study were to examine 1) the patterns of the impacted maxillary wisdom tooth and 2) the proximity of the impacted maxillary wisdom tooth to the maxillary sinus in relation to oroantral perforation during the removal of a maxillary wisdom tooth. MATERIALS AND METHODS: This retrospective study reviewed the clinical records and dental pantomograms of patients who underwent the removal of maxillary wisdom teeth under general anesthesia over a 6-month period. Using a modified version of the Archer classification of impacted maxillary wisdom teeth, types of impaction were classified according to depth, angulation of impaction, and proximity to the floor of the sinus. Clinical records showed the occurrence of oroantral perforation. RESULTS: In total, 845 maxillary wisdom teeth were removed; 66.8% were by routine extraction and 33.2% were removed surgically. The most common type of impaction was vertical followed by mesioangular. Most impacted teeth were at the level between the occlusal and cervical level of the adjacent second molar. Only 7 of the 278 excised wisdom teeth produced an oroantral perforation. Only 0.9% of all cases with a close sinus approximation showed an oroantral perforation. Statistical analysis with the Fisher exact test showed statistically significant associations of depth of impaction (P < .001), eruption status (P = .001), and long-axis position (P < .001) to the occurrence of an oroantral perforation. Sinus approximation showed no association with the occurrence of an oroantral perforation (P = 1.000). CONCLUSION: The depth of impaction of the maxillary wisdom tooth is a possible predictor of the possibility of oro-antral perforation if removal of the tooth is required. Due to the limitation of the radiograph, it is not a reliable to use radiographic close proximity of the sinus to predict the occurrence of oro-antral perforation when the maxillary wisdom tooth is removed.

Apical root resorption of incisors after orthodontic treatment of impacted maxillary canines: a radiographic study.

INTRODUCTION: The purpose of the study was to evaluate impacted maxillary canines as risk factor for orthodontic apical root resorption. METHODS: The sample comprised 66 patients treated with fixed appliances. Thirty-two patients with a unilateral impacted maxillary canine, which was distanced from the roots of the incisors at a preliminary phase of treatment before bonding, formed the impaction group, and 34 patients without impactions served as the controls. Root shortening was calculated by using pretreatment and posttreatment intraoral radiographs. Inclination of the eruption path of the impacted canine relative to the midline, axis of the lateral incisor, and nasal line, root development, and the medial and vertical positions of the impacted tooth were recorded on orthopantomograms and lateral cephalometric films. The follicle/tooth ratio was evaluated by using periapical radiographs. RESULTS: No significant difference in apical resorption of the maxillary incisors was detected between the impaction and control groups, or between the incisors of the impacted and contralateral sides in the same subject. Likewise, no difference in the severity of root resorption was found between the incisors of impacted side alone and the incisors of the control group. Mesial and vertical inclinations of the impacted canines were negatively related to a lateral incisor's root resorption. No correlations were found between resorption and medial or vertical position of the crown of the canine. The follicle/tooth ratio was significantly related to the mesial inclination of the impacted canine, but not to root resorption. CONCLUSIONS: An impacted maxillary canine, after being distanced from the incisor roots, does not seem to be a risk factor for apical root resorption during orthodontic treatment.