Angulation Of Teeth Research Articles

Mesiodistal Angulation of Each Whole Tooth in Patients With Nonsyndromic Unilateral Cleft Lip and Palate: Is it Symmetrical?

To assess the symmetry of the mesiodistal angulations of maxillary and mandibular teeth in patients with unilateral cleft lip and palate (UCLP) and compare with the class I control group without cleft lip and palate (CLP). A retrospective study. University department. The panoramic radiographs of 45 orthodontically untreated individuals with nonsyndromic UCLP (mean age 14.13 ± 0.75 years) and 45 skeletal class I individuals without CLP (mean age 14.01 ± 0.74 years). The line passing through the most superior points of the condyles was taken as the reference. The angle between the long axes of the maxillary and mandibular teeth and reference line was measured digitally. With the purpose of determining condylar symmetry, mandibular asymmetry index measurements were utilized. Independent samples t test and paired samples t test were used for the statistical analyses. The mesiodistal angulation of the maxillary and mandibular teeth in patients with UCLP was measured. The differences between the contralateral sides were determined and compared to class I individuals without CLP. No statistically significant difference was found among the condylar asymmetry in both groups (P > .05).The significant differences between the cleft and noncleft sides in the UCLP group was observed in the maxillary central, canine, first premolar and second molar teeth (P < .001, P = .002, P = .013, P = .012, respectively). The mean differences were found to be higher in the central and lateral incisors, canines and first premolars in the UCLP group (P < .001, P = .006, P = .001, respectively). Although the cleft-side maxillary central incisors tipped in a distal direction in patients with UCLP, the canine and first premolar showed more inclinations toward the mesial direction.

The study of tooth angulation and inclination for bracket design of Deutromalay race: A comparison study to white race

BackgroundThe Indonesian population consist of Deutromalay and Protomalay races, with the Deutromalay race being most of the population. In 1972, Lawrence F. Andrews introduced the “six keys of normal occlusion,” which was based on a white sample. This study aimed to identify standard tooth angulation and inclination in the Deutromalay race, which might help in future development of bracket prescription specific to the population. MethodsThis cross-sectional study was conducted on a representative sample of 190 subjects (112 male and 78 female subjects) aged 14 to 22 years from the Deutromalay population. Data collection was performed by two investigators following the methodology prescribed by Andrews for measuring tooth crown angulations and inclinations. Inter-rater reliability was measured with kappa statistics. Data were analyzed using SPSS software, version 25. Independent-samples t-tests were used for significance testing. The alpha level for statistical significance was set at 0.05, two-tailed. ResultsThe kappa statistic came out to be 0.80, which showed substantial agreement. The results of the t-test for tooth angulation and inclination found significant differences between male and female subjects for some teeth within the Deutromalay sample. In addition, significant differences were found for most teeth between the Deutromalay and white samples. ConclusionsSignificant differences in crown angulation and inclination values exist for most teeth in the Deutromalay sample studied compared with the white norms reported by Andrews. This points to the possible need to develop a new preadjusted bracket prescription specific for the Indonesian (Deutromalay) population.

Prevalence of patterns of impacted third molars

Aim: As the patterns of impaction can affect the treatment plan of removing or remaining the impacted tooth, the difficulty of surgery, and the post-surgical complications, this survey aimed for assessment of the mandibular wisdom tooth impaction patterns in terms of angulation and depth in the north population of Iran. Materials and Methods: 196 Panoramic radiographs were gathered from patients attending to the department of oral and maxillofacial surgery of GUMS in 2018-2019. To perform this retrospective study the prevalence of impaction, angulation, and the level of the eruption were assessed. The data were analyzed by SPSS 16. Results: This study found that the most common pattern of impacted mandibular third molars was level B in terms of depth and mesioangular in terms of angulation. Conclusion: The current study notes the importance of determining the angulation and level of wisdom tooth in designing the pre-surgical treatment and in post-surgical complaints

Comparison of the collum angle of incisors and canines in skeletal malocclusions – A CBCT study

The collum angle that defines the crown root angulation of the single rooted teeth plays an important in treatment planning. To compare the collum angle (crown root angulation) of maxillary and mandibular anterior teeth in different skeletal malocclusions using Cone Beam Computed Tomography (CBCT). Sixty subjects were categorized into four groups (fifteen subjects in each group) Class I, Class II division 1, Class II division 2 malocclusion and Class III based on Angle classification, Wits and ANB. The collum angle of maxillary and mandibular anterior teeth was measured using CBCT. One way ANOVA, Post hoc comparison with Tukey HSD and Paired t-test were used to analyse the measured data. The collum angle of corresponding right and left side teeth were averaged. Thus, the mean and standard deviation of the collum angle (n-30) were generated for maxillary and mandibular central incisors, lateral incisors, and canines. A statistically significant increase was observed in the maxillary central incisors of Class II division 2 and mandibular lateral incisors of class III malocclusion. The collum angle was increased in mandibular canines of Class III malocclusion when compared with class I and Class II division 2 malocclusion. The collum angle was negative in mandibular central incisors of Class II division 2. No statistically significant difference was observed in the mean collum angle between the right and left side anterior teeth in all the four groups. A variation in Collum angle was observed between the maxillary and mandibular anterior teeth and malocclusions. The effect of these variations in collum angle in torque expression and biomechanics should be kept in mind by the orthodontist before treatment planning especially in Class II division 2 malocclusion.

Teeth angulations after class II treatment with the Jones Jig followed by fixed appliances: A retrospective panoramic analysis

The purpose of this study was to compare the maxillary mesiodistal dental angulations of Class II malocclusion patients treated with the Jones Jig, followed by fixed appliances, with normal values of a historical control group, on panoramic radiographs. The sample comprised 80 panoramic radiographs of 40 patients divided into two groups. Eligibility criteria included patients with predominantly dental Class II malocclusion; the presence of all teeth up to the second molars and no previous orthodontic treatment. The experimental group was composed of 60 radiographs of 20 patients treated with the Jones Jig distalizer followed by fixed appliances. The radiographs were taken at pre-treatment (T0), post-distalization (T1), and post-treatment (T2). The historical control group comprised 20 radiographs of 20 subjects with untreated normal occlusion. The mesiodistal axial angulations of all maxillary erupted teeth were evaluated with the Dolphin Imaging software. Intragroup comparisons in the experimental group were performed with repeated measures analysis of variance (ANOVA), followed by Tukey tests. The experimental group at T2 versus the control group were compared with t tests. After distalization, significant distal angulation of the molars (110.58°±8.54, P<0.000) and mesial angulation of the second (86.43°±8.08, P<0.000) and first premolars (80.11°±8.01, P<0.000) was observed. However, this was corrected after comprehensive fixed orthodontics (100.54°±6.53; 98.95°±7.00; 94.92°±6.44; P<0.000, for these teeth, respectively). Intergroup comparisons resulted in first molars, premolars, canines, and central incisors significantly more distally angulated in the experimental group, when compared to the control. In general, at the end of orthodontic treatment, patients treated with the Jones Jig distalizer followed by fixed appliances presented more distally angulated maxillary teeth when compared to an untreated group with normal occlusion.

Characterization of Mandibular First Molar Extraction Space for Dental Implant Placement Using CBCT Imaging – A Retrospective Analysis

Objective: The aim of this study was to evaluate the consequences of untreated mandibular first molar extraction space on alveolar bone and adjacent teeth to suggest appropriate implant size selection and direction of its placement to achieve a favorable relationship between the prosthetic part, the implant fixture, and the adjacent teeth. &#x0D; Methods: This observational study evaluated 183 CBCT of mandibular first molar extraction spaces to measure adjacent teeth angulations, height, width, and length of interdental crestal bone. Besides interdental distance, unopposed teeth overeruption, and inferior alveolar nerve canal position were measured, and the continuous data have been subjected to the normality test to calculate the Mean and median of the variables.&#x0D; Results: Mean molar-premolar, molar-bone crest, and premolar bone crest angles were 48.5±12.14◦, 46.4±11.9◦ , and 84.8±9.0◦ , respectively. Mean molar-premolar crestal bone lengths 11.66 ± 2.32 mm. The median bone width was 6.46 mm, and the median interdental distance was 7.54 mm. The mean alveolar crest to the roof of the inferior alveolar nerve canal was 16.42 ± 2.82 mm.&#x0D; Conclusions: Untreated mandibular first molar extraction spaces significantly compromised interdental spaces and bone properties for proposing proper implant size, positions, and angulations.

Influence of facial index, facial profile, lip size, and angulations of teeth on gingival characteristics of anterior teeth: A gender-based evaluation.

A prime component in an esthetic and pleasing appearance of face is the proportionate presence of different compositions of the face. The present study aimed to evaluate the association between facial index, facial form, lip size, and angulation of anterior teeth with periodontal phenotype in males and females. This cross-sectional study included 100 consecutive periodontally healthy orthodontic patients equally divided based on gender in two groups. The facial parameters including the Facial index (FI), lip size, and Gingival thickness (GT) for maxillary and mandibular incisors were measured using a digital vernier calliper. Maxillary and mandibular incisors inclination was measured using cephalometric analysis. Significant differences were observed among both the genders in terms of FI and facial forms, upper lip size, and angulations of mandibular anterior teeth and the periodontal phenotype. The GT was found to be strongly associated with the FI and mandibular anterior teeth angulation. The FI, and teeth inclinations are associated with the GT and shows sexual dimorphism. The evaluation of the periodontal phenotype and anthropometric parameters is essential during diagnosis and treatment planning for potential orthodontic patients and prediction of its influence on the periodontal tissues. The gingival thickness varies with the facial index, facial form, teeth inclination, and lip size and thereby can be used to predict the pros and cons of orthodontic treatment and the need for prior periodontal therapy.

Effect of force direction and tooth angulation during traction of palatally impacted canines: A finite element analysis

Treatment of a palatally impacted canine (PIC) is associated with demanding anchorage control, increased treatment duration, and undesirable side effects. Accurate PIC localization and force application impact treatment success. The objective of this research was to determine the stresses on the PIC when subjected to initial force activation in various directions (buccal, vertical, and distal) and relative to impaction severity. Thirty PICs from 21 scans underwent finite element modeling. A prototype 3D model was reconstructed and segmented into its anatomic components. Each PIC was precisely positioned in the prototype model according to impaction position. Stresses in response to a (1.0N) force in the distal, vertical, and buccal directions were evaluated at different levels of the root (apical, middle, and cervical). Distal and buccal forces yielded higher stress (6.64 and 6.41kPa, respectively) than the vertical force (5.97kPa) on the total PIC root and the apical and cervical root levels, but not at midroot. Statistically significant differences between severity groups were found mostly at the apical level among all force directions, except between distal and buccal forces in the higher severity group. In this group, stress was greatest at the cervical level with the buccal force significantly different from the stresses generated by either the distal or the vertical force. Vertical forces generated the lowest stresses. Differentially distributed stresses over the root reflected an initial tipping movement. Greater cervical stresses from the buccal force indicate resistance to movement, suggesting treatment initiation with vertical and distal forces over buccal forces, particularly with severely inclined canines.

Association Between Third Molar Impaction Status and Angle or Condylar Fractures of the Mandible: A Retrospective Analysis

The aim of our study was to evaluate the correlations between mandibular third molar impaction status and mandibular angle and condylar fractures. This retrospective cross-sectional study included patients with unilateral and isolated angle or condylar fractures. Patient records and panoramic radiographs were evaluated. The predictor variables included the presence, impaction status (Pell and Gregory [P&G] classification), and angulation (Winter classification) of the third molar. The outcome variable was the type of fracture, whereas other predictor variables included demographic factors such as age, gender, and fracture etiology. Bivariate (χ2 test) and logistic regression analyses were conducted to estimate the associations between variables and the outcome. The sample was composed of 164 angle fracture (mean age, 31.6±12.3years; 83.5% male) and 115 condylar fracture (mean age, 41.9±16.8years; 76.5% male) patients. A third molar was present in 72.6% of the angle fracture group and 54.8% of the condylar fracture group (P=.002). Deep impactions (classes IC, IIC, IIIB, and IIIC) exhibited an odds ratio (OR) of 3.60 for angle fractures (P<.001). No association was found between tooth angulations and the type of fracture. According to logistic regression analysis, older age (adjusted OR, 1.05; 95% confidence interval [CI], 1.03 to 1.07), P&G class I impaction (OR, 1.86; 95% CI, 1.09 to 3.20), and P&G class A impaction (OR, 1.91; 95% CI, 1.12 to 3.24) were significantly associated with condylar fractures whereas the presence of a third molar (OR, 0.46; 95% CI, 0.28 to 0.76) or P&G class B impaction (OR, 0.287; 95% CI, 0.12 to 0.69) was associated with angular fractures. P&G class II or III and class B impaction status was significantly associated with angle fractures, whereas missing or fully erupted (class IA) third molars significantly correlated with condylar fractures.

Estimation of root inclination of anterior teeth from virtual study models: accuracy of a commercial software

BackgroundThe aim of the study was to assess the accuracy of commercially available software in estimating anterior tooth root inclination from digital impressions of the crowns of the teeth.Subjects and methodsFollowing sample size calculation and application of inclusion and exclusion criteria, 55 anterior natural teeth derived from 14 dry human skulls were selected. Impressions were taken and plaster study models were fabricated. Plaster models were scanned using the high-resolution mode of an Ortho Insight 3D laser scanner. The teeth on the digital scans were segmented and virtual roots were predicted and constructed by the Ortho Insight 3D software. The 55 natural teeth were removed from the dry skulls and scanned using the Identica extraoral white-light scanner in order to calculate their actual root angulation. The teeth were scanned twice, once to acquire the crown and the cervical part of the root, and a second time to acquire the remaining part of the root, including the apex. The two scanned segments were joined in software by superimposing them along their common part. The accuracy of the digital models generated by the Ortho Insight 3D scanner in predicting root angulation was assessed by comparing these results to the corresponding measurements of the 55 natural teeth. The long axes of the tooth models obtained from the software prediction and the scanning of the actual teeth were computed and the discrepancy between them was evaluated. The error of the methods was evaluated by repeating the measurements on 14 teeth and showed an acceptable range.ResultsThe predicted tooth angulation was found to differ significantly from the actual angulation, both statistically and clinically. The angle between the predicted and actual long axes ranged from 2.0 to 37.6°(average 9.7°; median 7.4°). No statistically significant difference was found between tooth categories.ConclusionsFurther investigations and improvements of the software are needed before it can be considered clinically effective.

A Clinical, Radiographic and Histological Study of Unerupted Teeth in Dogs and Cats: 73 Cases (2001-2018).

Lack of dental eruption may be accompanied by development of dentigerous cysts and has also been rarely associated with neoplasia. However, little information is available on prevalence of unerupted teeth and associated lesions in dogs and cats. The main objective of this study was to describe the epidemiologic data of canine and feline dental patients with unerupted teeth, and assess the prevalence of associated dentigerous cysts and tumors. Secondary aims included the evaluation of possible factors implicated in cystic development, and description of the histological features of dentigerous cysts. Medical and dental records, intraoral photographs, intraoral radiographs of client-owned dogs and cats with clinically missing teeth examined between 2001 and March 2018 were reviewed. Collected data included signalment, reason for presentation, number, type, depth of inclusion and angulation of unerupted teeth, presence of cystic lesions or tumors, abnormalities affecting involved teeth, histopathological findings, performed treatment and outcome. Seventy-three animals (69 dogs and 4 cats) with 113 unerupted teeth were included. The most frequent unerupted tooth in dogs was the first premolar teeth (78%), followed by the canine and third molar teeth. Dentigerous cysts were diagnosed associated with 48 (44.4%) teeth in dogs and one out of five unerupted teeth in cats. The affected teeth in dogs were predominantly in horizontal inclination (40%) and in soft tissue inclusion (77%). Brachycephalic canine breeds were overrepresented. The only unerupted tooth in boxer dogs was the first premolar tooth (32 teeth). Ninety percentage of boxers with unerupted teeth developed associated lesions (25 dentigerous cysts and one tumor). Two ameloblastomas (one in a dog and one in a cat) and one osteosarcoma (in a dog) were diagnosed in association with three unerupted teeth. Histology was essential in diagnosing two odontogenic cysts not evident on radiographs. In all cases that were followed-up, treatment (i.e., extraction, extraction and surgical curettage, or operculectomy) appeared successful. Untreated dentigerous cysts showed progression at re-examination. None of the unerupted teeth without evidence of cyst at the time of diagnosis showed incipient cystic development. None of the evaluated factors were associated with lack of eruption and/or development of associated lesions.

A cone-beam computed tomography analysis of angulation and inclination of whole tooth and clinical crown in adults with normal occlusion.

To identify the mesiodistal angulation and faciolingual inclination of whole tooth and clinical crown in Chinese young adults with normal occlusion, by examining CBCT digitalized images. Forty-two volunteers, who presented with normal occlusion and without previous orthodontic treatment, were selected for this study. The subjects were advised to take dental CBCT and the digital images of the dentition were obtained. The widely recognized University of Southern California (USC) root vector analysis was adopted to detect the angulation and inclination of the whole tooth, as well as of the clinical crown. No statistically significant difference was detected between male and female subjects. The fluctuations of the angulation and the inclination of the whole tooth from anterior to posterior in both arches manifested distinctive trends. The changes in maxillary dentition seem relatively marked, whereas those in mandibular dentition show less obvious, demonstrating moderate fluctuation both in angulation or inclination. The angulation and inclination of clinical crown are obtained and are shown positively correlated with that of each whole tooth. The normal range of the mesiodistal angulation and faciolingual inclination of whole tooth and clinical crown in Chinese adults with normal occlusion are identified. This study could establish clinical standards for designing 3D dental data-based orthodontic appliances for Chinese, and for providing the guidance for orthodontic treatment.

Heritability of teeth angulation and inclination in patients with overt malocclusion

To use 3-dimensional cone beam computed tomography (CBCT) images obtained on patients before treatment with dental malocclusion to calculate the heritability estimates of full-tooth angulation and inclination. A heritability estimate is a number between zero and one indicating the percentage of genetic factors involved in determining the phenotypic variation observed. CBCT images of 111 patients (51 sibships) were analysed measuring both tooth angulation and inclination using the Anatomage Invivo5 software for central incisor to second molar. The long axis of each tooth was defined and traced as the cusp tip of the most mesiobuccal cusp to 6mm coronal to the apex of the mesiobuccal root. SPSS statistical software was used to analyse the data and calculate the heritability estimates for each tooth type in the maxilla and in the mandible regardless of the side. Teeth inclination showed higher heritability estimates than tooth angulation. Furthermore, maxillary teeth showed higher heritability estimates than mandibular teeth and anterior teeth showed higher heritability than posterior teeth. Genetic effect was more evident on tooth inclination than tooth angulation, on anterior teeth more than posterior teeth, and on maxillary teeth more than mandibular teeth.

Pattern of Angulations and Common Indications for Extraction of Impacted Mandibular Third Molar at KMU-Institute of Dental Sciences, Kohat

Background: The extraction of an impacted mandibular third molar (MTM), with associated pathologies or clinical manifestations is an important and one of the most frequent decisions in dentistry. The angle formed by the longitudinal axis of second and third molar is used to determine angulation of impacted MTM. The aim of this study was to identify the pattern of angulations of impacted mandibular third molar and common indications for extraction associated with these angulations.Material and Methods: This descriptive cross-sectional study was carried out at Department of Oral &amp; Maxillofacial Surgery, Khyber Medical University Institute of Dental Sciences, Kohat, Khyber Pakhtunkhwa (KP) from November 2017 to July 2018. A total of 349 patients presenting with impacted mandibular third molars were included in this study. Name, age, gender, address, the angulation of the impacted tooth and the indication for extraction of the impacted tooth were recorded. Data comprising of qualitative and quantitative variables were analyzed using SPSS version 17.Results: Out of 349 patients, 206 were male and 143 females, with the male to female ratio of 1.4:1. The age range of the patients was from 18 years to 60 years with a mean age of 26 ± 6 years. The most common age group with impacted third molar was ≤ 25 years followed by 26 to 30 years’ age group. The most common angulation was mesioangular followed by vertical, horizontal and distoangular impacted mandibular third molar. Pericoronitis was the most common indication for extraction in all angulations except horizontal impaction where root resorption of the second molar was more common.Conclusion: Mesioangular is the most common angulation in impacted mandibular third molars. Pericoronitis is the main indication for all angulations of impacted mandibular third molars except horizontal angulation, occurring mostly in the third decade of life.

The effect of thickness of labial bone and angulation of mandibular anterior teeth on preoperative design of immediate dental implants

The effect of thickness of labial bone and angulation of mandibular anterior teeth on preoperative design of immediate dental implants

Orthodonticorthognathic treatment stability in skeletal class III malocclusion patients

To investigate stability of skeletal hard tissues, dental hard tissues and soft tissues after orthodonticorthognathic treatment in a long term. This study reviewed longitudinal changes in orthodontic-orthognathic patients of skeletal class III malocculsion, using lateral cephalometric radiographs in 3-12 years after treatment in comparison to treatment finishing. Twenty-two patients with skeletal Class III malocclusion following orthodontic-orthognathic surgery in Peking University School and Hospital of Stomatology from January 1, 2000 to January 1, 2009 were observed. The lateral cephalometric radiographs of the following stages were collected: treatment finishing (T1), 3 to 12 years after treatment (T2). Statistical analyses of cephalometrics were evaluated. Paired student t test was performed by SPSS 17.0. Data of all the 22 patients were studied in longitudinal timeline after treatment and 3-12 years after treatment. From T1 to T2, we evaluated 11-SN (angle between the upper incisors axis and SN plane), 11-NA angle (angle between the upper incisors axis and NA plane), 11-NA mm (perpendicular distance from upper incisors to NA plane), 11-41 (angle between the upper incisors axis and lower incisors axis), 41-NB angle (angle between lower incisors and NB plane), 41-NB (perpendicular distance from lower incisors to NB plane), 41-MP angle (angle between lower incisors and GoGn plane), and IMPA [angle between lower incisor and mandibular plane (tangent line to submandibular border)]. Most hard tissues of the teeth remained stable but upper anterior teeth angulations decreased, indicating by significantly reducing 11-SN (T1: 110.98°±6.77°; T2: 109.21°±5.80°; P=0.005); reducing 11-NA (T1: 28.31°±6.80°; T2: 26.49°±6.18°; P=0.002); increasing 11-41 (T1: 123.51°±8.14°; T2: 125.7°±10.01°; P=0.035). From T1 to T2, we also evaluated SNA (angle of sella-nasion-A-point), SNB (angle of sella-nasion-B-point), ANB (angle of A-point-nasion-B-point), GoGn-SN (angle between GoGn and SN plane), GoGn-FH (angle between GoGn and Frankfort plane), Y axis (angel between Sella-Gn and Frankfort plane), N-ANS (distance from nasion point to ANS point), ANS-Me (distance from ANS point to Menton point), N-Me (distance from nasion point to Menton point), ANS-Me/N-Me% (proportion of ANS-Me to N-Me), and FMA (angle between Frankfort and mandibular plane), Wits appraisal (horizontal distance between points A and B on functional occlusal plane). Skeletal hard tissues also remained relatively stable, only N-Me value changed significantly with a decreasing facial height (T1: 124.98°±11.98°; T2: 122.4°±11.05°; P=0.024). From T1 to T2, we finally evaluated FH-NsPg angle (angle between NsPg and Frankfort plane), H angle (angel between H line and NB), FH-A'UL angle (angle between A'UL and Frankfort plane), FH-B'LL angle (angle between B'LL and Frankfort plane), UL-LL (angle between UL and LL), UL-EP (distance between UL and E line), LL-EP (distance between LL and E line), Sn-H (perpendicular distance between Sn point and H line), Nls-H (distance of nose-lip-sulcus to H line), Li-H (lower lip to H line), Si-H (lower lip sulcus to H line), and NLA (nasolabial angle, angle of Cm-Sn-UL-point). Soft tissues changes were observed in decreasing UL-EP [T1: (-2.78±2.20) mm; (-3.29±2.44) mm; P=0.02] and H angle (T1: 8.27°±3.71°; 7.32°±3.83°; P=0.006). Other soft tissues remained relatively stable by retruding upper lip position and chin changes with no statistical significance. Orthodontic-orthognathic treatment can improve esthetics and occlusal function in patients of skeletal class III malocclusion with a stable long-term outcome.

Marginal bone loss and resorption of second molars related to maxillary third molars in panoramic images compared with CBCT.

Compare findings among observers in panoramic images (PAN) and cone beam CT (CBCT); and assess findings in PAN as indicators for marginal bone loss and resorption observed in CBCT. 120 impacted maxillary third molars with PAN and CBCT were included. Four observers assessed morphological features: (1) tooth angulation; (2) number of roots; (3) bony impaction (yes/no) and pathology; (4) marginal bone level at the second molar (normal/>3 mm = bone loss); (5) resorption in the second molar (no/superficial/< half way through the dentin/≥ half way through the dentin/involving the pulp); (6) size of follicular space (normal/> 4 mm(cyst)). Percentage accordance and κ statistics described observer variation in PAN and CBCT. Logistic regression analyses tested findings in PAN as indicators for marginal bone loss or resorption observed in CBCT. κ values were fair and interobserver accordance was marginally higher in CBCT than PAN. Agreement between PAN and CBCT was 81-88% for marginal bone loss and 68-81% for resorption. Severe resorption was more often observed in CBCT. Mesio-angulated third molars and marginal bone loss interpreted in PAN significantly indicated marginal bone loss observed in CBCT (odds ration 17-34; p < 0.012; 8.8-52.8; p < 0.02). In contrast, findings in PAN were not significant indicators for resorption observed in CBCT (p > 0.05). In general, there was a fair agreement for marginal bone loss between PAN and CBCT, and PAN could significantly predict bone loss observed in CBCT. However, presence of resorption observed in CBCT could not be determined from PAN, and more severe resorption was observed in CBCT. CBCT is indicated if resorption in the second molar needs to be assessed.

Mesiodistal angulation of posterior teeth in orthodontic patients with different facial growth patterns.

Background. Mesiodistal and buccolingual angulations of teeth are variable in different malocclusion classes. This study aimed to assess the mesiodistal angulation of posterior teeth in orthodontic patients with vertical, normal, and horizontal facial growth patterns. Methods. This descriptive, cross-sectional study evaluated 150 lateral cephalograms of orthodontic patients. According to cephalometric analysis, facial growth patterns were divided into three groups of normal, horizontal, and vertical (n=50). The angulation of maxillary and mandibular posterior teeth was then measured. Data were analyzed using SPSS 22. Results. The results showed an increase in the mean angle of maxillary and mandibular posterior teeth relative to palatal and mandibular planes in patients with a vertical facial growth pattern. Conversely, their angulation decreased relative to the bisected occlusal plane (BOP). The angulation of posterior teeth decreased relative to palatal and mandibular planes and increased relative to the occlusal plane with an increase in overbite. The mean angle of all maxillary teeth relative to the palatal plane was significantly greater in open bite patients compared to normal and deep bite patients. This value in patients with normal bite was significantly greater than that in deep bite patients (P<0.05). Conclusion. The current results revealed that in patients with a vertical growth pattern, all the posterior teeth had a forward inclination. Conversely, in patients with a horizontal growth pattern, the teeth had a backward inclination.

Mesially Directed Inclination of Posterior Teeth Contributing to Maxillary High Canine, and Changes during Orthodontic Treatment

Objective: The aim of study was to evaluate the nature of mesiodistal angulation of the posterior teeth in patients with maxillary high canine, and to identify possible associations of crowding with mesial axial angulation of the maxillary posterior teeth. Methods: The present study included seven Japanese male and 23 Japanese female patients. Study models were analyzed to evaluate the effectiveness of orthodontic treatment. A protractor was used to measure crown angulations, which were measured with reference to the posterior angle between the functional occlusal plane (FOP) and the long axis of the clinical crown of the lateral teeth and first molars. A sliding digital caliper was used to measure dental arch widths. Changes in the rotation of the maxillary molars were analyzed using “occlu-sograms”, which were printed from photographs of the occlusal aspect of the study model. Results: The maxillary teeth interacted with one another in the alveolar bone, resulting in progressive mesial tipping of the posterior teeth before orthodontic treatment. After orthodontic treatment, the angle relative to the FOP exhibited a significant increase, indicating that the maxillary teeth underwent distally directed uprighting (P P < 0.01). Meanwhile, the rotation of the posterior teeth did not exhibit any significant changes. Conclusions: Based on the results, both uprighting of mesially tipped lateral teeth and expansion of narrow dental arches could prove to be keys to success in space regaining or correction of high canines and mild crowding.

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.