Prevalence of malocclusion and occlusal traits in the early mixed dentition in Shanghai, China

Analysis of prefabricated myofunctional appliances with different overjet and bumper designs: a three-dimensional finite element analysis

BACKGROUND

Prefabricated myofunctional appliance can guide tooth eruption, improve dentition alignment, correct myofunctional disorders and harmful oral habits. However, its application to skeletal discrepancy may result in unsatisfactory tooth inclination. This study aimed to construct a novel appliance with overjet design to avoid this side effect and investigated its shape and mechanical changes under occlusion using three-dimensional finite element method.

METHODS

We established three samples of prefabricated myofunctional appliances. The first one was edge to edge without overjet, and the outer shield of both jaws were flattened. The second one was 3 mm overjet with stepped the outer shield. The last one was 3 mm overjet, and the outer shield of both jaws were flatted, which meant the front wall of lower jaw was strengthened with bumper, termed as lower bumper. A complete dentition model was applied to the study. 150 N occlusal force was applied to each type of appliance and the deformation displacement and the changes in stress was recorded.

RESULTS

The deformation was significant in the incisors regions, especially in the vertical and lateral dimensions. The maximum displacements of 3 mm overjet with step shield group were 7.08 mm (vertical), 3.99 mm (lateral), and 2.90 mm (sagittal), while it decreased to 3.92 mm(vertical), 1.94 mm (lateral), and 1.55 mm (sagittal) in overjet with bumper group. Moreover, the upper molar regions exhibited higher vertical and sagittal displacement in 3 mm overjet with step shield group, which were 3.03 mm (vertical) and 1.99 mm (sagittal), and the bumper design could decrease the maximum displacement to 1.72 mm (vertical) and 0.72 mm (sagittal). In addition, the Von Mises stress of appliances was analyzed, and results indicated that 3 mm overjet with step shield generated higher stress than other groups, with the maximum Von Mises stress was 0.9387 MP, which were 0.5858 and 0.5657 MP in edge to edge group and 3 mm overjet with lower bumper group, respectively.

CONCLUSION

The prefabricated myofunctional appliances may cause deformation during occlusion. Compared to step shield group, the application of lower bumper exhibited better resistance to occlusal force.

Malocclusion among children in Vietnam: Prevalence and associations with different habits

Background

This study aimed to measure the prevalence of malocclusion and identify associated factors among elementary school students in Vietnam.

Method

A cross-sectional study was conducted from March to December 2022 at six primary schools located in the province of Thai Binh, Vietnam. A total of 873 students were recruited for research purposes. Students were classified into normal, malocclusion classes I, II and III. Bad habits were examined. Multivariate logistic regression was used to detect associations.

Results

The prevalence of malocclusion was 60.7 %; 19.0 % had Class I, 31.0 % had Class II and 10.7 % had Class III. Having finger sucking habit was associated with Class I malocclusion (OR: 3.28), and Class II malocclusion (OR: 3.22). Having lip biting habit was related to a higher odds of having Class II malocclusion (OR = 4.37) Class III malocclusion (OR = 6.83). Having tongue thrusting habit was associated with higher odds of having Class I (OR: 5.25), and Class II malocclusion (OR: 6.42). Mouth breathing was related to a higher likelihood of having Class II malocclusion (OR = 2.71). Having early loss of deciduous teeth was associated with a higher odds of having Class III malocclusion (OR = 3.83).

Conclusion

Findings showed high prevalence of malocclusion, mostly class II, in elementary students in Vietnam. Bad habits such as finger sucking, biting the lower lip, tongue thrusting, mouth breathing, and early loss of deciduous teeth play important roles in developing malocclusion, which should be considered in the development of interventions.

Evolution of the Terminal Plane from Deciduous to Mixed Dentition

(1) Introduction: Correct development and growth of the dental arches and occlusion in the deciduous dentition is crucial for physiological occlusion in the permanent dentition. The present study evaluates the evolution of the terminal plane and canine occlusion class in the same children from deciduous to mixed dentition. (2) Materials and methods: The study included 257 children (164 girls and 93 boys) aged 3-5 years in the first phase and 8-10 years in the second phase. The chi-square test was used for the comparison of qualitative variables, while analysis of variance (ANOVA) or the Mann-Whitney U-test, Kruskal-Wallis test, and Wilcoxon test were used in the case of quantitative variables, as applicable. Statistical significance was considered for p < 0.05. (3) Results: The most common terminal plane in the first phase of the study was a bilateral flush plane (70%), followed by distal and mesial, with few differences between them. In the second phase, the most common terminal plane was mesial, followed by bilateral flush and distal. There were no statistically significant differences according to gender. Canine occlusion in the first phase was predominantly bilateral class I, followed by class II and class III. Similar results were recorded in the permanent dentition, except for a lesser percentage of children with canine class II. Molar occlusion in the second phase was predominantly class I, followed by half cusp class II and full cusp class II and class III. (4) Conclusions: The present study shows that knowing the age range in which maximum dental development and growth in both arches occurs may contribute to avoiding malocclusions and the possible need for orthodontic-orthopedic treatment, resulting in improved outcomes and greater stability.

Prevalence of orthodontic treatment needs in permanent dentition in the population of Gulf Cooperation Council countries: A systematic review and meta-analysis of observational studies

The aim of this systematic review and meta-analysis was to comprehensively analyze the existing information on the prevalence of the need for orthodontic treatment in the permanent dentition stage among populations in Gulf Cooperation Council (GCC) countries. For observational studies in GCC countries, the key terms were electronically searched in Science Direct, PubMed, Embase, Cochrane Reviews, Google Scholar, and Sage databases (1990-2021). The bias risk for the selected studies was evaluated using the modified Strengthening the Reporting of Observational Studies in Epidemiology statement. Thirteen studies reported on the prevalence of orthodontic treatment needs among 33,134 children in GCC countries in permanent dentition with an age range of 11-19 years satisfied the inclusion criteria. Out of the 13 studies, 9 reported on the prevalence of malocclusion, 11 reported on the prevalence of occlusal traits, and 12 reported on the prevalence of orthodontic treatment needs as per the Dental Health Component (DHC) of Index of Orthodontic Treatment Need (IOTN), 4 reported as per both DHC and Aesthetic Component (AC) of IOTN, and 1 reported as per only AC of IOTN. Meta-analysis of the included studies indicated that the pooled malocclusion prevalence rate was 10.60% (confidence interval [CI] 95%: 0.093-0.076) with 8.58% Class I (CI 95%: 0.074-0.188), 2.09% Class II (CI 95%: 0.014-0.058), and 0.93% Class III (CI 95%: 0.005-0.018) malocclusions. The most prevalent type of occlusal trait was spacing (13.10%, CI 95%: 0.018-0.169), followed by crowding (4.96%, CI 95%: 0.017-0.091). The pooled prevalence of borderline and definite needs for orthodontic treatment based on DHC and AC of IOTN was 0.82% (CI 95%: 0.014-0.035), 1.13% (CI 95%: 0.011-0.091), 4.08% (CI 95%: 0.009-0.114), and 2.06% (CI 95%: 0.002-0.048), respectively. The findings were heterogeneous (P < 0.05). These findings indicated that the prevalence of malocclusion and orthodontic treatment needs was not high in the GCC population.

Prevalence and influencing factors of malocclusion in adolescents in Shanghai, China

BACKGROUND

The main purpose of the study was to investigate the prevalence and related risk factors of malocclusion in permanent dentition among adolescents in Shanghai, and provide basic data for government's preventive strategies and intervention plans.

METHODS

1799 adolescents aged 11-15 years old from 18 middle schools in 6 districts of Shanghai were recruited to investigate oral health status and related risk factors using cluster random sampling method in 2021. Malocclusion and caries were examined by on-site inspection. The investigation criteria referred to Bjoerk and the recommendation of the WHO. The malocclusion inspection items included molars relationship, canine relationship, overbite, overjet, midline displacement, anterior crossbite, posterior crossbite, scissors bite, crowding and spacing. The subjects were asked to fill in a questionnaire including parents' education level, oral health behaviors and dietary habits. The chi-square test and logistic regression analysis were used to analyze the relationship between malocclusion and risk factors.

RESULTS

1799 adolescents were included in the study and the prevalence of malocclusion in adolescents in Shanghai was 83.5%, and the proportion of molar relationship class I, class II, and class III was 48.9%, 14.7%, and 19.0%, respectively. The most common occlusal characteristic of malocclusion was anterior crowding, followed by midline irregularities and deep overbite, with prevalence rates of 44.8%, 39.0% and 38.6%, respectively. The prevalence rate of adolescents with caries was 34.3%. Those who had dental caries and preferred soft food were more likely to have abnormal occlusal characteristics (p < 0.05).

CONCLUSION

The prevalence of malocclusion in adolescents in Shanghai is high, so it is of great significance to strengthen oral health education, allocate proper preventive strategies and carry out the early correction if necessary.

Efficacy of an innovative Herbst appliance with TADs for patients with hyperdivergent class II malocclusion: study protocol for a randomised controlled trial

INTRODUCTION

Class II treatment with mandibular retrusion often involves the Herbst appliance due to its efficiency and low requirement of cooperation. Despite its advantages, it causes side effects concerning the occlusal plane and pogonion in terms of clockwise rotation that hinder the desired mandibular advancement for hyperdivergent patients. In this study, we will use a newly designed Herbst appliance, and a protocol that is accompanied by TADs for vertical control to avoid maxillary clockwise rotation. We hypothesise that the effect of the Herbst appliance with the vertical control approach will be beneficial for maintaining or even decreasing the skeletal divergence in hyperdivergent class II patients compared with conventional Herbst treatment.

METHODS AND ANALYSIS

This study is a randomised, parallel, prospective controlled trial that will study the efficacy of Herbst with or without vertical control in children with hyperdivergent skeletal class II malocclusion. A total of 44 patients will be enrolled and randomised in a ratio of 1:1 to either Herbst treatment or Herbst treatment with vertical control. Participants will be recruited at the Shanghai Stomatological Hospital, Shanghai, China. The primary endpoint is the change in the angle indicating the occlusal plane and Sella-Nasion plane from baseline (T0) to the primary endpoint (T2) on cephalometric measurements by lateral X-ray examination. Important secondary outcomes include the root length of the anterior teeth, and the assessment score of the Visual Analogue Scale Questionnaire, etc. Safety endpoints will also be evaluated.

ETHICS AND DISSEMINATION

This study has been approved by the ethics committee of the Shanghai Stomatological Hospital (Approval No. (2021) 012). Before enrolment, a qualified clinical research assistant will obtain written informed consent from both the participants and their guardians after full explanation of this study. The results will be presented at national or international conferences and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR2100049860, Chinese Clinical Trial Registry.

Association of crossbite with vertical skeletal growth patterns: A retrospective study

Crossbite is a type of malocclusion in which teeth are positioned more buccally or lingually than their corresponding opposing tooth in the upper or lower dental arch, resulting in a lateral mismatch of the teeth in the dental arches. Crossbite can be unilateral or bilateral, and it can be anterior or posterior. The link between crossbite and skeletal growth pattern remains uncertain. The current study aimed to find the prevalence of crossbite in subjects visiting a private dental hospital and evaluate if there is any association between crossbite and skeletal growth pattern. Data required for the study were procured from the dental information archiving software. The data were sorted and entered into an Excel spreadsheet. IBM SPSS software version 23 was used to conduct the statistical analysis. Graphs and tables were used to interpret the findings. the prevalence of crossbite was found to be 6.4%. Subjects with horizontal growth pattern commonly had crossbite, but no statistical significance (P = 0.07), standard deviation (1.011), was noted. There was no statistically significant association between different skeletal growth patterns however subjects with horizontal growth pattern reported more commonly with crossbite.

Severity of mandibular arch crowding in different sagittal malocclusions

Mandibular anterior crowding is caused by a variety of factors. Mandibular incisor crowding can be caused by a number of causes including incisor and molar inclination, early loss of deciduous molars, mandibular growth, and oral musculature. The study was aimed to perform an association of the lower anterior crowding severity with gender and type of malocclusion. The current study was performed in a hospital setup and data about mandibular arch crowding patients were collected from the Records management system of a Private Dental Hospital in Chennai city. All the patient data on Mandibular arch crowding were sourced and tabulated after which statistical analysis with SPSS-IBM was done. Data collection was done over a period from June 2019 to February 2021. The entire study sample size was 634 case records. The result obtained from the statistical analysis was found that nearly 46% of the patients were found to have Mandibular arch crowding with female predilection (50%). The most commonly associated age groups were children than adults (63.2%) associated with mild type of crowding (65.1%). The most commonly involved malocclusion was found to be Class 1 (88.4%) Mild imbrications of the lower arch were common and were seen mainly in subjects with Class I malocclusion. Female subjects presented with more prevalence of mandibular arch crowding when compared to male subjects. Children were more affected by crowding than adults.

Prevalence of Orthodontic Malocclusions in Healthy Children and Adolescents: A Systematic Review

The purpose of this study was to systematically review the literature regarding the prevalence of malocclusion and different orthodontic features in children and adolescents. Methods: The digital databases PubMed, Cochrane, Embase, Open Grey, and Web of Science were searched from inception to November 2021. Epidemiological studies, randomized controlled trials, clinical trials, and comparative studies involving subjects ≤ 18 years old and focusing on the prevalence of malocclusion and different orthodontic features were selected. Articles written in English, Dutch, French, German, Spanish, and Portuguese were included. Three authors independently assessed the eligibility, extracted the data from, and ascertained the quality of the studies. Since all of the included articles were non-randomized, the MINORS tool was used to score the risk of bias. Results: The initial electronic database search identified a total of 6775 articles. After the removal of duplicates, 4646 articles were screened using the title and abstract. A total of 415 full-text articles were assessed, and 123 articles were finally included for qualitative analysis. The range of prevalence of Angle Class I, Class II, and Class III malocclusion was very large, with a mean prevalence of 51.9% (SD 20.7), 23.8% (SD 14.6), and 6.5% (SD 6.5), respectively. As for the prevalence of overjet, reversed overjet, overbite, and open bite, no means were calculated due to the large variation in the definitions, measurements, methodologies, and cut-off points among the studies. The prevalence of anterior crossbite, posterior crossbite, and crossbite with functional shift were 7.8% (SD 6.5), 9.0% (SD 7.34), and 12.2% (SD 7.8), respectively. The prevalence of hypodontia and hyperdontia were reported to be 6.8% (SD 4.2) and 1.8% (SD 1.3), respectively. For impacted teeth, ectopic eruption, and transposition, means of 4.9% (SD 3.7), 5.4% (SD 3.8), and 0.5% (SD 0.5) were found, respectively. Conclusions: There is an urgent need to clearly define orthodontic features and malocclusion traits as well as to reach consensus on the protocols used to quantify them. The large variety in methodological approaches found in the literature makes the data regarding prevalence of malocclusion unreliable.

Deleterious oral habits related to vertical, transverse and sagittal dental malocclusion in pediatric patients

BACKGROUND

Malocclusion is highly reported among mixed dentition cases. Therefore, we aimed to determine the relationship of dental malocclusions in the vertical, transverse, sagittal planes with deleterious habits in pediatric patients.

METHODS

A cross-sectional analytical study was carried out on 155 children aged 6-12 years attended at the clinic of the School of Dentistry of Universidad Nacional Mayor de San Marcos in 2017.

RESULTS

Among 155 evaluated patients, 45.3% had vertical malocclusion, 52.0% had sagittal malocclusion and 13.6% had transverse malocclusion. The most frequent type of malocclusion in the vertical plane was anterior deep bite (22.2%), in the transverse plane, the edge-to-edge bite (7.1%) and the anterior crossbite (6.5%) were less frequent. Finally, in the sagittal plane, Class II Div 1 (20%) and Class III (20.7%) were the most frequent. Among the most common deleterious habits, anteroposition (58.7%) and mixed breathing (51.0%) were observed in contrast to the habit of retroposition, lip sucking and mouth breathing, which were the least frequent. Considering age and sex, children who have an atypical swallowing habit are more likely to have malocclusion in all three planes of space.

CONCLUSIONS

It is concluded that there is an association between the deleterious habits with the different types of malocclusions in the different planes of the space, being the atypical swallowing a habit that should be early diagnosed and treated interdisciplinary.

Malocclusion and occlusal traits among dental and nursing students of Seven North-East states of India

BACKGROUND

Any irregularity of the teeth or a mal-relationship of the dental arches is known as malocclusion. Among all the oro-facial problems, tooth decay is considered the most prevalent one followed by periodontal disease and dental malocclusion. Dental malocclusion is not a life-threatening condition. However, it is closely related to an individual's self-esteem and psychosocial wellbeing. The prevalence of malocclusion varies among different ethnic groups, age-groups, and gender.

OBJECTIVES

This study was conducted with the objective to find out the prevalence of normal occlusal traits and to identify the proportion of different types of malocclusions among dental and nursing students of Seven North-Eastern states studying at a tertiary care Medical Institute.

METHODS AND MATERIALS

This cross-sectional study included 432 students with a mean age of 21.42 years, who satisfied the inclusion criteria. Inclusion criteria consisted of the presence of all permanent teeth with or without third molars. The oral cavity was examined using a sterile mouth mirror and flashlight followed by evaluation of all the occlusal relationships in centric occlusion position (COP). COP was achieved by asking the participant to swallow, and then to bite on his or her teeth together. The occlusion traits were assessed as normal occlusion or malocclusion using the first permanent molars as described by E.H. Angle and deviation from line of occlusion. Descriptive statistics like mean and proportions were calculated.

RESULTS

The prevalence of normal occlusal traits was 48.4%, and that of malocclusion was 51.6%. Class I malocclusion was most prevalent occlusal trait followed by Class II malocclusion and Class III malocclusion showed the least prevalence.

CONCLUSIONS

Class I malocclusion was most prevalent followed by Class II malocclusion and Class III malocclusion showed the least prevalence.

Oral health-related quality-of-life scores differ by socioeconomic status, mother's level of education, dental visits and severity of malocclusion in mixed dentition of eight-to-ten-year-old schoolchildren

Objective

To determinate the association among socioeconomic status subject’s mother’s level of educational attainment, dental visits, and malocclusion in mixed dentition with on the OHRQoL of eight-to-ten-year-old children.

Methods

A cross-sectional study conducted, in 2019, on Mexican children from households of different socioeconomic status (SES). The prevalence of malocclusion was evaluated using the Dental Aesthetic Index (DAI), while the SES of the participants’ households was evaluated using the three categories (corresponding to a high, middle, or low-income household) stipulated by the Consejo Nacional de Población (CONAPO or National Population Council). Oral Health-related Quality of Life (OHRQoL) was evaluated using the Child Perceptions Questionnaire (CPQ_8-10). Poisson regression models were performed for the analysis of the data obtained.

Results

A total of 79.4% of the subjects presented some type of malocclusion in mixed dentition, which was, by severity, as follows: definite (31.3%); severe (25.6%); and, very severe (22.5%). The Poisson regression model revealed a greater negative impact on the following four CPQ_8-10domains for children with severe/very severe malocclusion [RR]: oral symptoms [2.78]; functional limitations [2.72]; emotional well-being [2.59]; and, social well-being [3.99]. A greater impact on the four CPQ_8-10domains was found for children from a low-income household than for children from a high-income (p < 0.001) household. Furthermore, poor oral hygiene, lack of dental visits, and the mother’s level of educational attainment (<9 years) were found to have a negative impact on OHRQoL.

Conclusion

The findings of the present study demonstrated that the severity of malocclusion was associated with a greater negative impact on the OHRQoL of children, while those children who face greater health inequalities are likely to report a greater negative impact on their OHRQoL.

Orthodontic treatment need and occlusal traits in the early mixed dentition among 8-9-year old Saudi children

Purpose

The present study aimed to assess the prevalence of occlusal traits and to evaluate the orthodontic treatment need among children aged 8-9 years in Al Ahsa, Eastern region of Saudi Arabia.

Materials and methods

A descriptive cross-sectional study was conducted among 282 Saudi children who were randomly selected from those visiting dental outpatient clinics at the College of dentistry in King Faisal University, AlAhsa. All the children were evaluated using the DHC and AC components of Index of Orthodontic Treatment Need (IOTN). Descriptive statistics, chisquare test and Fisher's Exact test were used for data analysis with statistical significance set at p< 0.05.

Results

The most prevalent malocclusal trait was crowding (39.7%) followed by increased overjet (28.4%). About 30.9% and 17% of the children were in definite need for orthodontic treatment according to DHC and AC of IOTN, respectively. There was no statistical difference in the distribution of DHC (p=0.116) and AC (p=0.177) scores between the gender.

Conclusion

This study demonstrated high percentage of malocclusal traits and orthodontic treatment need in the mixed dentition period among 8-9-year-old children in the Eastern region. Emphasis should be placed on early orthodontic screening and treatment in the mixed dentition stage of dental development.

A Comparison of Craniofacial Characteristics between Two Different Adult Populations with Class II Malocclusion-A Cross-Sectional Retrospective Study

Simple Summary

One of the most common orthodontic problems, Class II malocclusion, may lead to an increased risk of dentoalveolar trauma, psychosocial issues, and a possible compromised quality of life. Oftentimes clinicians use normative standard values to which each patient is compared to identify deviations from the norm, in order to determine a patient-specific treatment plan. Large inter-individual and inter-ethnic variability, however, is sometimes not considered. In our study, we compared the cephalometric characteristics between two different ethnic groups (South Indian and Vietnamese) with the phenotype of Class II malocclusion in the hope of better understanding this variation and its implications in treatment planning to achieve satisfactory outcomes.

Abstract

The dental, skeletal, and soft-tissue characteristics of a particular malocclusion can differ based on ethnicity, race, age, sex and geographical location with Class II malocclusion being one of the most prevalent malocclusions encountered in orthodontic clinical practice. The broad understanding of the characteristics of vertical skeletal and dental parameters in patients with Class II malocclusion can help clinicians to identify patterns and variations in the expression of this phenotype for better treatment outcomes. Hence, we compared the craniofacial characteristics of skeletal and dental Class II malocclusion traits from Indian and Vietnamese individuals to analyze the vertical skeletal and dental patterns in both population groups. The sample comprised of lateral cephalograms from 100 young adults with Class II malocclusion, of which fifty (25 males and 25 females) were from South India and the other 50 age- and sex-matched adults from Vietnam. The lateral cephalometric radiographs were digitized into anonymous image files and were traced and assessed for 16 vertical skeletal and dental parameters. The ANB angle was greater in males (+1.4 deg; p < 0.001) and females (+1.9 deg; p < 0.001) in the South Indian population. The Vietnamese males had a larger mandibular plane angle, articular angle, anterior facial height and lower anterior facial height compared to the Indian males. The Vietnamese females had larger mandibular plane and articular angles compared to the Indian females. The skeletal class II malocclusion was more severe in the South Indian compared to the Vietnamese adults. The Vietnamese sample showed a generalized tendency towards a more vertical skeletal growth pattern and in males this pattern seemed to be due to the dentoalveolar component. The Vietnamese females showed a tendency towards a vertical growth pattern, but without apparent contribution by the dentoalveolar component.

Fracture strength of endodontically treated lateral incisors restored with new zirconia reinforced rice husk nanohybrid composite

Background

This study aimed to compare the fracture strength, fracture pattern and type of fracture of endodontically treated maxillary lateral incisors restored with new zirconia reinforced rice husk nanohybrid composite.

Material and Methods

Eighty mature permanent maxillary lateral incisors from patients age range of 30-60 years with single canal were selected and randomly divided into: Group 1 – RCT + nanofilled composite (Filtek), Group 2 – RCT + microhybrid composite (Zmack), Group 3 – RCT + new nanohybrid composite (Zr-Hybrid) and Group 4 - Intact teeth (control). Standardized mesio-palatal-distal cavity was prepared, and endodontic treatment was carried out using crown-down technique until size 30, tapered 0.04. Obturation was completed using single cone technique with gutta-percha and AH plus sealer. Cavity access was restored with respective composite resins. Next, teeth were stored in incubator for 24 hours and subdivided into aged and unaged subgroups. Teeth in aged subgroups were subjected to 2500 thermal cycles for 5ºC, 37ºC and 55ºC with 30 seconds dwell time and 5 seconds transfer time. After that, root surfaces of teeth were covered with silicone-based material and placed in boxes filled with acrylic until the cemento-enamel-junction (CEJ) level. They were then tested under Universal Testing Machine until fracture occurred. Samples were then viewed under Leica microscope to determine the fracture pattern and type of fracture. Data analyzed using One-way ANOVA complimented by post hoc Tukey HSD and paired sample T test for fracture strength. Fracture pattern and type of fracture were analyzed using Chi-square test. Level of significance was set at p<0.05.

Results

Significant differences were observed (p<0.05) with Group 3 demonstrating the highest fracture strength followed by Group 4, Group 1 and lastly Group 2 in both aged and unaged subgroups respectively. A significant decreased in fracture strength was noted in Group 1 and Group 2 (p<0.05) as number of thermocycle increased but no significant differences were noted in Group 3 and Group 4 (p>0.05). Besides, Group 3 and Group 4 showed higher rate of favorable fracture pattern, followed by Group 1 and lastly Group 2. Most favorable fracture pattern was noted to exhibit horizontal fracture type (86.36%), whereas most unfavorable fracture pattern exhibited vertical fracture type (77.78%).

Conclusions

Endodontically treated teeth restored with new zirconia reinforced rice husk nanohybrid composite (Zr-Hybrid) demonstrated higher fracture strength than commercialized composite resins especially after artificial ageing. Zr-Hybrid showed similar fracture pattern to those of intact teeth with higher rate of horizontal fracture type.

Key words:Fracture strength, fracture pattern, composite resin, rice husk, Zirconia.

Prevalence of malocclusion and orthodontic treatment needs among 12-15 years old school children in Patna, Eastern India

Context

The people around the world are concerned about the aesthetic oral-facial structures as it is more important in interpersonal interactions and dictates vocal, physical, and emotional communication.

Aims

The present study was conducted to assess the severity of malocclusion and orthodontic treatment need among 12-15-year-old school children of Patna, Eastern India.

Settings and Design

A cross-sectional study design was used to assess the severity of malocclusion using Dental Aesthetic Index (DAI) index among 12-15-year-old school-going children.

Methods and Material

A specially prepared and pretested format, exclusively designed for recording all the required and relevant general information and other clinical findings was used in the study. The sample size consisted of 902 children from middle schools (Government and Private) in Patna.

Statistical Analysis Used

Chi-square test was done for the categorical data to compare differences between two independent groups. Data were presented as Mean ± SD and "P" value of less than 0.05 was accepted as indicating significance.

Results

Around 5.3% had a DAI score of ≤25 which signifies that there is "no abnormality or may have minor malocclusion"; 15.3% had a DAI score of 26-30 which signifies that there is "definite malocclusion"; 6% had a DAI score of 31-35 which signifies that there is "severe malocclusion" and 4% had a DAI score of ≥36 which signifies that there is "very severe or handicapping malocclusion". The finding was more commonly seen among 14 years age group.

Conclusions

It can be concluded from the present study that the prevalence of malocclusion is reasonable high in this part of the region, and it is very important to bring in more awareness at the school level as primary prevention can be the most effective tool in control this menace.