Cephalometric association of mandibular size/length to the surface area and dimensions of the frontal and maxillary sinuses.

OBJECTIVE: This study aimed to determine the cephalometric association of mandibular size/length to the surface area and dimensions of the frontal and maxillary sinuses. MATERIALS AND METHODS: This descriptive study was conducted on 116 digital lateral cephalograms of 38 patients with skeletal Class I malocclusion (normal), 40 patients with skeletal Class II malocclusion with mandibular deficiency, and 38 patients with skeletal Class III malocclusion with mandibular excess. Both male and female patients were included. Using AutoCAD 2016 software, the anteroposterior dimension, height and surface area of the frontal and maxillary sinuses, mandibular body length and cephalometric indices including anterior and posterior cranial bases, and growth pattern indices were measured on lateral cephalograms. RESULTS: Dimensions and surface area of the frontal and maxillary sinuses in skeletal Class III malocclusion were greater than those in other groups. These variables were significantly correlated with the mandibular body length. The coefficient for the correlation of height, width, and surface area of the frontal sinus with mandibular body length was 0.253, 0.284, and 0.490, respectively. The coefficient for the correlation of height, length, and surface area of the maxillary sinus with mandibular body length was 0.346, 0.657, and 0.661, respectively. These variables (except for the frontal sinus width) had a significant correlation with the anterior and posterior cranial bases. The frontal sinus width had a significant correlation with the anterior cranial base. These variables in males were greater than those in females. CONCLUSION: The dimensions and surface area of the frontal and maxillary sinuses in skeletal Class III malocclusion were greater than those in other groups. These variables (except for the frontal sinus width) had a significant correlation with the anterior and posterior cranial bases and mandibular body length.

Buccolingual course of the inferior alveolar canal in different mental foramen locations: A cone beam computed tomography study of an Iranian population.

CONTEXT: Better understanding of the anatomical location and course of the mandibular canal is necessary to avoid damaging inferior alveolar nerve. AIMS: The aim of this study was to investigate the buccolingual course of the inferior alveolar canal (IAC) in different mental foramen locations, using cone beam computed tomography. MATERIALS AND METHODS: Three hundred and twelve hemimandibular images were evaluated in this study. The location of mental foramen in relation to the apices of mandibular premolar and molar teeth were recorded. Nine measurements (in millimeters) were taken at the level of the IAC and posterior mandibular premolar and molar root apices. Relative distances of IAC to buccal and lingual mandibular cortex were calculated for different mental foramen types. STATISTICAL ANALYSIS USED: Data were analyzed by one-way analysis of variance and P < 0.05 was considered to be statistically significant. RESULTS: The distribution of subjects according to the type of mental foramen includes: Type 1 = 50.3% (at the level of second premolar apex), Type 2 = 33% (between the apices of first and second premolars), and Type 3 = 16.7% (between the apices of second premolars and first molars). The buccolingual ratio of the IAC position was statistically significant in different mental foramen types (P = 0.00). CONCLUSION: The position of IAC was affected by the location of the mental foramen. The direction of IAC gradually changed from lingual to buccal and from posterior to anterior.

Evaluation of the Course of the Inferior Alveolar Canal: The First CBCT Study in an Iranian Population.

BACKROUND: The frequent anatomical variations of the inferior alveolar nerve (IAN) course should be considered prior to any treatment in this area. The aim of this study was to evaluate the course of the inferior alveolar canal (IAC) as it appears in the archived CBCT images of the mandible. MATERIAL/METHOD: This cross- sectional study evaluated a sample of 156 CBCT examinations. The pattern of the IAC was evaluated and the prevalence of different patterns according to age and gender were recorded. In order to find the frequency of mandibular canal type among different ages, the patients were put into the three age groups (20-29, 30-44 and 45-59).The data were analyzed using Chi-square test and the significance level was set as p≤.05. RESULTS: Out of 156 patients, 52 canals was straight type, 52 had Catenary type and 52 of them were presented with Progressive descending type. There was not statistically significant difference between two genders (Pv=0.092). According to the type of the IAC course, there was a not statistically significant difference between the three age groups (Pv=0.32). CONCLUSIONS: Cone beam computed tomography is a useful method for precise assessment of the IAC course.

Pneumatized Articular Eminence and Assessment of Its Prevalence and Features on Panoramic Radiographs.

OBJECTIVES: Pneumatized articular eminence or tubercle (PAT) is an air cell cavity in the zygomatic process of the temporal bone. Pneumatization of articular eminence may be seen incidentally on panoramic radiographs (PRs) as a unilocular or multilocular radiolucent defect. The aim of this study was to assess the prevalence and the pattern of PAT on PR in an Iranian population. MATERIALS AND METHODS: A total of 3,098 PRs belonging to 1,735 females and 1,363 males were retrospectively investigated for the presence and radiographic features of PAT. All PRs were taken for routine dental examination. Chi-square test, univariate odds ratio (OR) and corresponding 95% confidence interval (95% CI) and binary logistic regression were used for statistical analysis. RESULTS: Overall, PAT was found in 2.1 % of cases including 41 females and 23 males (with a mean age of 33.23±12.43 and 35.64±13.24 years, respectively, range 19-69 years). There were 40 unilateral and 24 bilateral cases (total: 88 PATs) including 49 unilocular and 39 multilocular cases. There was no significant difference in PAT between males and females or different age groups (P>0.05 and all CIs included 1.00). Binary logistic regression indicated that there was no relationship between the presence of PAT and age or sex. CONCLUSION: Knowledge about this anatomical variation is helpful for clinicians who are planning to perform temporomandibular joint surgery. They should assess the radiographic imaging thoroughly before the surgery. It can also provide valuable information to understand the differential diagnosis of pathological entities in this region.

Location of Mental Foramen in a Selected Iranian Population: A CBCT Assessment.

INTRODUCTION: Mental foramen (MF) is an important anatomic landmark in dentistry and knowledge about its variable locations (L) and type of emergence (TE), has an effect on the sufficiency of local anesthesia and safety of surgical procedures. The aim of this study was to evaluate the L and TE of this radiographic landmark as well as the presence of accessory MF, by means of cone-beam computed tomography (CBCT). METHODS AND MATERIALS: In this cross sectional study, a total of 156 CBCT images were retrieved from the archive of a private radiology clinic and were then evaluated for the position of MF and its TE and the existence of accessory foramina in the body of mandible. The extracted information was compared in both genders, in both sides of mandible and among three different age groups (20-29, 30-44 and 45-59 years). The Pearson chi-square and Fisher's Exact tests were used for statistical analysis. The level of significance was set at 0.05. RESULTS: Second premolar was the most common anterolateral L of MF; in general, 48.7% of right and 51.9% of left MFs were located at the apex of second premolar. Anterior and straight ET were more common in right and left side, respectively. Accessory MF was present in only 8 (5.1%) of cases. CONCLUSION: The possible presence of accessory MF should not be overlooked for avoiding the occurrence of a neurosensory disturbance during surgery and implant insertion.

Correlation between symphyseal morphology and mandibular growth.

BACKGROUND: This study sought to assess symphyseal morphology in adolescents with different mandibular growth patterns (MGPs) in order to see if a relation exists. MATERIALS AND METHODS: In this study the symphyseal parameters (height, depth, and ratio) of normal subjects were compared with four groups with malocclusion (cl III vertical, cl II vertical, cl III horizontal, and cl II horizontal). These groups (15 samples each) were matched (for sex and cervical maturation stage [CVMS]) based on their cephalograms and patient charts. Growth patterns were differentiated by seven vertical parameters and the Wylie analysis. After confirmation of normality of the groups and similarity of their variances the two-way analysis of variance (ANOVA) was used for analysis of data assessed by adjusted chi-square (P < 0.001). The comparison of cases with the normal group was performed by the Dunnett method. Intraclass Correlation Coefficient (ICC) was used for evaluation of intraobserver reliability. RESULTS: We found the symphyseal ratio to have a significant correlation with the MGP (P < 0.001). The symphyseal ratio (Height/Depth) was small in a mandible with vertical growth pattern Cl II or Cl III. Conversely, a horizontal growth pattern of a Cl II or Cl III mandible was associated with a larger ratio of the symphysis in comparison with the normal group. The symphyseal ratio was also found to be greater in females. CONCLUSION: The symphyseal ratio was found to be strongly associated with the MGP.