The relationship of anterior occlusion and skeletal variables with the frontal sinus index: An analytical cross-sectional study.

OBJECTIVE: To determine the relationship of anterior occlusion and skeletal variables with the frontal sinus index. METHODS: The retrospective, analytical, cross-sectional, study was conducted from July to November 2020 at Dr Ishratul- Ebad Khan Institute of Oral Health Sciences and Dow Dental College, Dow University of Health Sciences, Karachi, and comprised data from 2015 to 2018 related to pre-treatment lateral cephalograms for determining frontal sinus index and other cephalometric variables. The dental casts were observed for incisor classification. Patients with Class I incisors formed the comparison group, while the rest comprised 5 malocclusion groups. The frontal sinus was traced, and the sinus index was calculated. Data was analysed using STATA 15 and R 3.5.1. RESULTS: Of the 240 subjects, there were 40(16.66%) in each of the 6 groups; 155(64.6%) females and 85(35.4%) males. The mean age of the sample was 21.33±3.52 years (range: 16-29 years). The mean sinus index was higher in all malocclusion groups than the comparison group, but it was significantly higher only in Class II division 2 and anterior open bite groups (p<0.05). The only exception to the trend was Class II division 1 with and without contact in which the value was lower (p>0.05). The anterior cranial base length, sella-nasion mandibular plane angle, and upper incisor palatal plane angle significantly affected the frontal sinus index (p<0.05). CONCLUSIONS: The frontal sinus index could be considered an indicator of harmonious anterior occlusion.

Comparison of upper and lower lip position, length and thickness in sagittal and vertical malocclusion.

This study aimed to compare the upper and lower lips position, length, and thickness in different malocclusions, in randomly selected 180 patients' pre-treatment lateral cephalograms. The subjects were grouped sagittally by using Steiner's analysis and Wits appraisal and vertically based on Frankfort horizontal and mandibular plane (FHMP) angle and lower facial height. One-way ANOVA was applied to compare the upper and lower lip positions, thickness, and length in sagittal and vertical malocclusion and independent sample T test was applied for comparison between genders among soft tissue variables. Post-hoc Dunnett T3 was performed for comparison of lip variables in adjacent malocclusion groups. The level of significance was not less than or equal to 0.05. The anteroposterior position of the upper and lower lips with respect to E and S planes and upper and lower lip thickness varied significantly (p < 0.05) in all classes of sagittal malocclusion, whereas the anteroposterior (AP) position of the LL with respect to both planes and UL length between vertical malocclusion groups was statistically significant (p < 0.05). AP position and fullness of both lips have a significant association with sagittal malocclusion, whereas the AP position of the lower lip's and the length of upper lip is significantly associated with vertical malocclusion.

Association between Intercanine Width and Mandibular Dental Arch Forms.

A descriptive cross-sectional study was conducted to investigate the association between intercanine width and the mandibular arch form in 109 dentate subjects, who visited Orthodontics Department from October 2018 to December 2019. Using Vernier caliper, the intercanine width was measured as the distance between the left and right canines on each cast with the arch form, also categorized as tapered, square or ovoid, using predefined criteria. Spearman's rank correlation demonstrated highly significant association between intercanine width and mandibular dental arch forms, with p value of 0.005. Key Words: Dentate subjects, Mandibular arch forms, Inter-canine width, Sexual dimorphism, Mandibular dental cast.

Frequency and association of maxillary ectopic canine with incisor root resorption and dental agenesis.

OBJECTIVE: To assess the frequency of maxillary ectopic canine both buccally and palatally displaced with incisor root resorption and dental agenesis. METHODS: The cross-sectional study was conducted from April 8 to June 29, 2019, at the Department of Orthodontics, Dr. Ishrat Ul Ebad Khan Institute of Oral Health Sciences, and Dow Dental College, Dow University Of Health Sciences, Karachi, and comprised orthodontic patients diagnosed with maxillary ectopic canine eruption. Root resorption and agenesis were diagnosed on panoramic films. Root resorption was further confirmed by periapical radiographs. Data was analysed using SPSS 21. RESULTS: Of the 98 subjects, 86(87.8%) had buccally displaced canines of which 38(44.2%) were associated with root resorption, while 12(12.2%) patients had palatally displaced canines of which 10(83.3%) had root resorption (p=0.011). Overall, 30(30.6%) lateral incisors were resorbed, 7(7.1%) both central and lateral incisors, 5(5.1%) premolars, and 6(6.1%) both lateral incisors and premolars were resorbed. Agenesis was detected in 10 (10.2%) subjects (p=0.62). CONCLUSIONS: There was found to be no association of maxillary ectopic canines with incisor root resorption and dental agenesis.

Association of Gonial Angle on Panoramic Radiograph with the Facial Divergence on Lateral Cephalogram.

OBJECTIVE: To find the mean gonial angle values among different facial divergent cases. STUDY DESIGN: Cross-sectional descriptive study. PLACE AND DURATION OF STUDY: Karachi Medical and Dental College from October 2018 to December 2019. METHODOLOGY: Panoramic radiographs (OPG) and lateral cephalograms of 91 patients, 33 males and 58 females, were obtained. Sella-Nasion-Mandibular Plane (SNMP) angle was measured on lateral cephalogram and gonial angles were measured on panoramic radiograph. Subjects were divided into three groups as per SNMP angle as hypodivergent, normodivergent and hyperdivergent. A p-value of less than 0.05 was considered statistically significant. RESULTS: The mean value of the gonial angle in OPG among all the patients was 125.05° with a standard deviation 7.24°. The average gonial angle in males was 124.10° ±5.67° and in females was 125.59° ±7.99°. Out of 91 patients, 14 were hypodivergent, 28 were normodivergent and 49 were hyperdivergent. The mean values of gonial angle among these three groups were 119.77° ±6.05°, 123.66° ±5.50° and 127.36° ±7.52°. One-way ANOVA demonstrated highly significant differences in the values of gonial angles among three facial divergences (p=0.001). Post-Hoc Tukey analysis showed that there was a significant difference between gonial angle of hyperdivergent and hypodivergent cases (p=0.001). CONCLUSION: Gonial angle on panoramic radiographs (OPG) may provide useful knowledge about the facial divergence of the orthodontic patients. Key Words: Gonial angle, Facial divergence, Lateral cephalogram, Panoramic radiograph, Orthodontic diagnosis.

Comparison Of The Adaptability Of Two Fissure Sealants In Various Tooth Fissure Morphology Patterns: An In Vitro Experimental Study.

BACKGROUND: This study was conducted to compare the adaptation of resin-based sealants with that of Resin modified glass ionome-based sealants in various tooth fissure morphologies. METHODS: It was an in vitro experimental study done at the Dow University and NED University, Karachi, Pakistan. Ten extracted human molars were randomly assigned to two groups, (n=5) each. Fissure sealant material (Resin based sealant or resin modified glass ionomer-based sealant) was applied on the occlusal surface of the tooth according to manufacturer's recommendations. Specimens were thermocycled and then sectioned into three longitudinal parts in the bucco- lingual direction. Specimens were examined using scanning electron microscope for the adaptation of the sealant in the occlusal fissure. Mann-Whitney -U test and Kruskall-Wallis test were applied to compare the adaptability scores of sealant materials in the tooth fissure. Level of significance was kept at 0.05. RESULTS: There were no significant differences in the adaptability scores among U-shaped (p-value=0.35), V-shaped (p-value=0.89), IK-shaped (p-value=0.52), I-shaped (p-value- =0.41) and Y-shaped (p-value=1.00) fissure patterns. Similarly, there were no significant differences observed between the resin-based sealant (p-value=0.95) versus RMGIC based sealant (p-value=0.63) for the adaptability scores in various tooth fissure morphologies. CONCLUSIONS: No significant difference was found between resin-based sealants and resin modified glass ionomerbased sealants for the adaptation in various tooth fissure patterns.