Correlations between mandibular ramus height and occlusal planes in Han Chinese individuals with normal occlusion: A cross-sectional study

Objectives: The objective of the study is to determine the relationships between ramus height and occlusal planes (OPs) in Han Chinese individuals with normal occlusion. Materials and Methods: Two hundred and four participants with normal occlusion were included and their cephalograms were analyzed. The ramus height (Ar-Go), Frankfort horizontal plane-posterior OP (FH-POP), FH-anterior OP (FH-AOP) and FH-OP, anterior and posterior cranial base length, SNA, SNB, ANB, Frankfort-mandibular plane angle, SN-MP, jaw angle, and mandibular body length were measured on the subjects’ cephalograms. Pearson correlation coefficients were calculated among continuous variables. The ramus height was considered as dependent variable and the OPs as independent variables. Age, sex, and other cephalometric parameters were considered as possible confounding factors. Univariate and multivariate analyses were performed to determine whether the relationships were significant. Results: The FH-POP and FH-OP were moderately associated with ramus height, while the FH-AOP showed a weak association (P < 0.001). After adjusting age and sex, FH-POP, FH-AOP, and FH-OP showed significant negative associations with ramus height (β = −0.36, −0.28, and −0.37, respectively, P < 0.001). The OP flattened with the ramus height increased. After adjusting all the confounding factors, FH-POP and FH-OP showed significant negative associations with ramus height. The ramus height increased by 0.19 mm/1° flattening of FHPOP (β = −0.19, P = 0.002). Conclusion: After adjust age, sex, and other possible confounding factors, the FH-POP and FH-OP were associated with the ramus height. The flattening of FH-POP was associated with the increase of ramus height. The results should be treated with caution since it’s a cross-sectional study.

Evaluation of tongue posture & dimensions in relation to skeletal Class I and Class II patterns- A cephalometric study

Association of tongue posture with dental and facial skeletal pattern have been suggested in past. This study was undertaken to assess tongue posture and dimensions in Class I and Class II Dentoskeletal patterns to determine whether any correlation exists between tongue posture and skeletal pattern of an individual. Cephalograms of 150 individuals (aged 18-23 years), taken in Natural Head Position (NHP) and tongue at rest were divided into three groups i.e. Group 1 – Class I Normal occlusion, Group 2 – Class II Division 1 Normodivergent and Group 3 – Class II Division 1 Hypodivergent, consisting of 50 samples each. To ensure the rest position of tongue, patient was asked to relax for 30 seconds after coating the tongue with barium sulphate in midline and then to swallow, and the X-ray was taken at the end of swallowing. Each group was divided into two subgroups according to sex. Groups were constituted according to the Frankfort mandibular plane angle (FMA) angle. The subjects who had skeletal Class II pattern due to mandibular retrusion and not due to maxillary prognathism were only included in the study group. Statistical analysis was done using the software SPSS version 21.0. The statistical tests used were unpaired t-test and One-way ANOVA test with post-hoc bonferroni test. The p-value was considered significant if less than 0.05.The dorsum of the tongue was higher at back and lower in front in Class II Division 1 Hypodivergent group as compared to Class I Normal occlusion group (P&#60;.05). Tongue height and tongue length were significantly reduced in Class II Division 1 Normodivergent and Class II Division 1 Hypodivergent malocclusion groups when compared to Class I control group (P&#60;.05).The study supports the existence of a relationship between posture & dimensions of the tongue with Class I and Class II skeletal patterns.

Evaluation of possible reasons for asymmetries associated with Class II subdivision, Class II division 1 and normal malocclusion

: To evaluate and compare the asymmetries in subjects with two malocclusions that is Class II subdivision, Class II div 1 and normal occlusion.: 90 subjects ranging from 15 to 30 years divided into 3 groups A, B, C. Group A – Class II subdivision, Group B – Class II division I, Group C – Normal Class I occlusion. Angular, linear paired, linear unpaired measurements were calculated based on the Van De Coppell analysis using PA views.: Asymmetry was found in all the three groups where Group A patients showed greater degree of asymmetry near maxillary buttress and piriform aperture areas compared to the three groups. Group C patients showed greater degree of asymmetry in the occlusal plane angle. All the three malocclusions that is Class II div 1 Subdivision, Class II div 1 and Class I malocclusions showed equal amounts of asymmetry. Class II subdivision patients showed greater asymmetry near maxillary buttress area and piriform aperture. Class I malocclusion showed deviation in occlusal plane angle. Along with the lower third involving mandible, maxillary area also can equally show asymmetry in both skeletal and dental parameters.

Pediatric Rotary Files: Evolution to Revolution

The main goal of pulp therapy in primary dentition is to preserve the primary tooth thus protecting future normal occlusion. Routinely, pulp debridement and canal shaping are done by manual H-files, K-files, Broach, etc. Manual instrumentation may be time- consuming, thus impacting the behaviour of the child negatively. Thus arises the need for alternate instrumentation which will reduce the time required for treatment with better treatment outcomes. In 1988, Walia et al. introduced Nickel-Titanium (Ni-Ti), which revolutionized the discipline of Endodontics. These Ni-Ti files have advantage of shape memory and super elasticity thus improving the canal preparation and resulting in better shaped canals. In 2002, for first time Barr et al reported the use of rotary Ni-Ti files for the therapeutic purpose during Pulpectomy procedure in pediatric patient. He observed better acceptance by pediatric patient and good quality obturation. Till 2016, pulpectomy procedures were accomplished by the combination of hand files and adult rotary files. Adult rotary files are designed according to the morphology for permanent teeth and adult jaw size, thus the use of adult rotary files are in primary teeth may result in lateral perforation due to softer dentine of roots of primary teeth and may cause discomfort to the child thus making child unco-operative. But in 2016, Ganesh et al., pioneered the specialization of Paediatric Endodontics with his invention of specially designed rotary files. Their shape was specially designated for application in tortuous canals of primary teeth. Presently, a variety of pediatric rotary files like Kedo-STM (India), Pro AF Baby GoldTM (India),PrimePedoTM (India), DXL-ProPedoTM (India), NeolixTM (France),Denco® Kids files (China) and, Sani® Kid rotary files (China). This review is an album of these newer files and clinical and in-vitro research on them.

Lower Incisor Positions in Different Malocclusions and Facial Pattern

Aims: The position of lower incisor has been of significant concern when seeking orthodontic treatment plan, it has been recognized as one of diagnostic key and play an important in the development of normal occlusion and facial pattern. This study was aimed at the determination of lower incisor position and its possible association with different sagittal malocclusions and facial patterns. Study Design: Descriptive Cross-sectional Study Place and Duration of Study: Department of Orthodontics Institute of Dentistry Liaquat University Medical and Health Sciences (LUMHS) Jamshoro between June 2019 to July 2020. Methodology: Ninety-seven pre-treatment lateral cephalometric radiographies were taken, and they were classified sagittally into skeletal class I, II and III, and vertically into normodivergent, hyperdivergent and hypodivergent facial pattern using ANB and SNMP, respectively. Lower incisor position was assessed by means of FMIA and IMPA. One way analysis of variance (ANOVA) was applied to check any association between lower incisor position and sagittal malocclusion and facial pattern. P value of 0.05 was considered statistically significant. Results: The study sample consisted of 97 patients. The mean age of the patients was 25.55 SD ±3.93. The mean SNMP value was 28.84 SD ±7.354 and mean ANB value 4.809 SD ±3.85. Mean Incisor position based on IMPA was 98.598 SD ± 9.413 and FMIA 54 SD ±9.995. Intra and interobserver reliability was assessed with intraclass correlation coefficient values ranging between 0.825 and 0.990 respectively. The ANOVA test results showed significant relationship between the sagittal malocclusion and incisor position with P value .036. The Bonferroni analysis indicated that statistically significant association existed in term of lower incisor position between Class II and Class III malocclusion with P value .047. Test results further indicated that there is no significant difference in the position of lower incisor in relation to facial pattern with P value .355. Conclusions: Statistically significant association was found between lower incisor position with respect to the sagittal malocclusion. However, no significant association was found between facial pattern and lower incisor position.

Prevalence of Three-Rooted Deciduous Mandibular Molars in the Children of Northwestern Iran

Introduction. Although primary teeth have a determinative role in development of normal occlusion, few studies about anomalies related to deciduous dentition have been conducted so far. Regarding recent improvements in common knowledge and the importance of maintaining primary teeth until eruption of succedaneous teeth, identifying the morphology of primary teeth and probable variations is of great importance to achieve optimal therapeutic outcome. This study aims to determine the prevalence of three-rooted mandibular primary molars in a population of northwestern Iran. Materials and Methods. In this descriptive cross-sectional study, periapical radiographs of patients attending private oral and maxillofacial radiology offices in the northwestern region of Iran from 2017 to 2019 were retrospectively reviewed. A total of 300 cases in the 3– 10 -year age range having bilateral periapical radiographs from mandibular primary molars were screened. First and second primary molars were observed meticulously. Gender, side of the mandible (right or left), symmetry, overall prevalence, and prevalence considering the type of molar (D or E) were recorded and analyzed. Results. Overall prevalence of three-rooted mandibular primary molars was 9.33 % ( 28 / 300 ), 92.9 % of which were unilateral. The prevalence of teeth showing supernumerary roots among all teeth examined was 2.5 % ( 30 / 1200 ). Considering symmetry and gender, the occurrence of these three-rooted primary molars did not differ significantly (respectively, p = 0.832 and p = 0.541 ). However, there was a significant relationship between the occurrence of supernumerary roots and left side for three-rooted first molars and right side for three-rooted second molars ( p = 0.021 ). Conclusion. Obtained data show that three-rooted mandibular primary molars in children of northwest region of Iran have a prevalence of approximately 10 % which urges some specific considerations in exodontic and endodontic procedures.

Prevalence of Malocclusions in Autistic Patients in Isfahan

Introduction: Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders diagnosed by impairments in social interaction and communication with repetitive and restrictive stereotyped behavioral patterns. The Prevalence of autism has been reported to be increased in recent years. This study aimed to assess the prevalence of different types of malocclusion among ASD patients in Isfahan in 2018. Materials & Methods: In a descriptive and cross-sectional trial, 92 ASD patients were studied in the age range of 7-18 years at the center for autism patients in Isfahan. Clinical oral examinations of patients are taken to assess the involved malocclusions (Cl I, Cl II and Cl III malocclusions) and malocclusion traits (deep bite, open bite and cross bite) by an educated dental student under the supervision of an orthodontist under natural light. The data are reported using frequency and percentage indices. Results: Class I malocclusion had the highest prevalence 54.3% (50) among ASD patients and the prevalence of class II and class III were found to be 19.6% (18) and 7.6% (7) respectively. The frequency of malocclusions traits of deep bite, cross bite and the open bite were 27.2% (25), 18.5% (17) and 7.6% (7) respectively. Among of the total patients, 65.2% (60) showed normal bite and 18/5% (17) showed Normal occlusion. Conclusion: ASD patients showed class I, class II and class III malocclusions from the most to least frequency and the most frequent malocclusion traits were also deep bite, cross bite and open bite respectively.

PERBANDINGAN VALIDITAS ANALISIS MOYERS DAN ANALISIS SITEPU PADA MAHASISWA SUKU MINANG FAKULTAS KEDOKTERAN GIGI UNIVERSITAS ANDALAS

Background: Malocclusion is a deviation from normal occlusion of teeth, and the majority of malocclusion cases occur in the stage of mixed dentition. There are several methods in the analysis of mixed dentition, two of which are Moyers analytical method and Sitepu analytical method. This study aims to determine the comparison of validity between Moyers analysis and Sitepu analysis when used in Minang ethnic students at FKG UNAND. Methods: This study used an analytical descriptive method. The sample consisted of 50 Minang ethnic students at Dentistry Faculty (FKG) of Andalas University selected by purposive sampling technique. The data analysis used Mann-Whitney test for maxilla and Independent t-test for mandible. Result: The results show the existence of differences in the validity between Moyers analysis and Sitepu analysis if used to Minang ethnic students at FKG UNAND. Sitepu analysis was valid in maxilla and mandible (p > 0.05), while Moyers analysis was only valid in maxilla (p > 0.05), and in mandible showed the value of p < 0.05. Conclusion: The conclusion of this study is that there is validity difference between Moyers analysis and Sitepu analysis in Minang ethnic students of FKG UNAND, Sitepu method is valid in maxilla and mandible, while Moyers analysis is only valid in maxilla.

The Relation among Teeth and Maxillary Dental Arch Dimensions with Anterior Teeth Angulation and Inclination

Objectives. This study aimed at finding out whether anterior teeth angulation and inclination have a relationship with the maxillary teeth and dental arch dimensions. Methods. Fifty study models with normal occlusion were selected from the archive of the Department of Orthodontics at Baghdad Dental Faculty. Maxillary dental arch width and length at different points were determined in addition to measuring anterior teeth angulation, inclination, crown thickness, overjet, overbite, and Bolton’s ratios. The unpaired t-test and Pearson’s correlation coefficient test were used for data analysis. Results. No statistical gender differences were reported in all measurements except the dental arch widths and length where males had significantly higher mean values. Only the maxillary incisor’s inclination showed a direct weak significant correlation with the total arch length. Conclusions. The inclination of upper incisors had a minimal effect on increasing dental arch length.

DEVELOPMENT OF OCCLUSION

There are several reasons why pediatric dentist should understand the development of dental occlusion. One of the major objectives of orthodontic treatment is to correct occlusal problems. Much of the need for this treatment could be avoided if children received the proper dental care at earlier ages. Development of occlusion is a genetically and environmentally conditioned process, which shows a great deal of individual variations, and consequently, for the development of an acceptable occlusion, quite a remarkable co-ordination of different events is necessary. The development of occlusion depends on a number of conditions, like muscular pressure, habits, availability of space, etc. This development is coincident with the growth of all tissues associated with the dental apparatus, including the nose, maxillary sinuses, facial bones and muscles. Failure in one part of the development process may lead to anomalies, or else may be compensated for by other developmental processes. Thus Proper care of the developing deciduous and permanent teeth, both at the dental office and at home, is important for the appropriate development of occlusion. and timely diagnosis followed by appropriate interception can prevent any developing malocclusion. This article is an overview which depicts (1) periods of development of occlusion, (2) outline the development of normal occlusion in the pediatric patient and (3) explain what occlusion of the teeth is and why it is important.