Akhter Husain

Work-related musculoskeletal disorders among dental surgeons: A pilot study

Aim: To describe the work-related musculoskeletal disorders among on-job dental surgeons. Objectives: To identify the musculoskeletal disorders in terms of perception of pain and stiffness experienced by the dental surgeons due to the rigors of dental work, to determine the prevailing working environment with particular reference to dental work station in relation to musculoskeletal disorders, and to find the association between pain and stiffness experienced by the dental surgeons and the selected socio-demographic variables. Materials and Methods: The study was conducted on 30 graduated dental surgeons having a work experience of 1 year or more, post graduates and faculty members of various specialties at Yenepoya Dental College Hospital, Mangalore. The subjects were selected randomly from the hospital and they were given closed-ended questionnaire to find out perception of pain and stiffness experienced in the past 6 months. The observation of the working environment was done by walk-through observational survey. Results: The study showed that 6.6% dental surgeons always experienced shoulder pain, while 83.3% dental surgeons sometimes experienced back pain and 70% sometimes experienced neck pain. Majority of the dental surgeons (73.3%) experienced stiffness in the back and 23.3% experienced severe pain in their neck. It was observed that the number of patients attended per day by the dental surgeons had a significant association (P = 0.024) with the pain they experienced in their hip/thigh region. The frequency of pain experienced by the dental surgeons in the hip/thigh and knee joints also showed a significant association (P = 0.037) with the height of the dental surgeons. Conclusion: The study revealed that various socio-demographic variables contributed to the musculoskeletal disorders experienced by the dental surgeons. However, the number of patients attended per day by the dental surgeons vis-à-vis pain experienced in the back, wrist, and hip/thigh was significant.

Kissing molars: An unusual unexpected impaction

Impacted molars have been widely reported. However, kissing molars is a rare finding which refers to impacted molars which have occlusal surfaces contacting each other in a single follicular space and roots pointing in opposite directions as reported in this case. This is the second case of kissing molars involving third and fourth molar and the only case fulfilling the criteria of kissing molars.

Effect of intrusive and retraction forces in labial and lingual orthodontics: A finite element study

Objectives: Lingual orthodontics differs in biomechanics as compared to labial system and has biomechanical advantages. Although theoretical approaches have explained the differences between labial and lingual orthodontics, the finite element method (FEM) may be better suited to analyze these differences. This study analyzes the effect of vertical and horizontal forces together on the tooth using FEM. Materials and Methods: An extracted right maxillary central incisor was radiographed and was used to create a solid model using ANSYS. The geometric model was converted into a finite element model with the help of ANSYS software. The model consists of 27,000 elements and 30,000 nodes. Two force vectors (vertical and horizontal) were applied labially and lingually at 3 different heights- 4 mm, 5 mm and 6 mm from the incisal edge. Results: In the labial system, the net force vector passes through the center of resistance (CR) and brings about intrusion. The net force vector in lingual orthodontics does not pass through the center of resistance and produces lingual tipping of the incisors. Conclusion: Intrusion and retraction forces bring about tipping of incisors in lingual orthodontics. The same amount of intrusion and retraction forces brings about intrusion of incisors in labial orthodontics. Therefore, direction and amount of forces should be carefully and judiciously applied after taking into consideration the resultant biomechanical differences.

An adjunctive minor surgical procedure for increased rate of retraction

Introduction: Orthodontic treatment is based on the principle that if prolonged pressure is applied to the tooth, tooth movement will occur as the bone around the tooth re-models. In this study osteotomy of buccal alveolar plate and undermining of interseptal bone was performed at premolar extraction site and rate of en-masse retraction and canine retraction was evaluated. Materials and Methods: Patients between the age of 18 and 25 years, requiring retraction of anterior teeth are selected for the study. Osteotomy with undermining of interseptal bone at the extraction site was performed. The procedure was performed on all four quadrants. Results: The average retraction in the maxillary arch was 0.98 mm/quadrant in 3 weeks, i.e., a total retraction of 5.89 mm in a span of 9 weeks. The average retraction in the mandibular arch was 0.96 mm/quadrant in 3 weeks, i.e., a total retraction of 5.75 mm in a span of 9 weeks. Conclusion: This method of achieving faster en masse retraction immediately after extraction definitely reduced the initial retraction time. We recommend that such procedure must be carried out with appropriate anchorage conservation methods.

Presurgical Nasoalveolar Molding Therapy Using Figueroa's NAM Technique in Unilateral Cleft Lip and Palate Patients: A Preliminary Study.

OBJECTIVE The objective of the study was to evaluate the results of nasoalveolar molding (NAM) in the treatment of patients with unilateral cleft lip and palate using a modified technique in a South Indian population. STUDY DESIGN The design was a prospective study with blinded measurements. The sample constituted 10 complete unilateral cleft lip and palate (UCLP) patients who underwent NAM therapy by the same operator. Direct extra and intra oral anthropometric measurements were done using a digital vernier caliper before and after NAM therapy. A photographic evaluation was also done to rate the nasal deformity post NAM therapy. The differences between measurements were statistically analyzed using paired t tests. RESULTS The extra oral measurements revealed a statistically significant increase in bi-alar width, columellar length and width. The intraoral measurements demonstrated a statistically significant reduction in anterior alveolar cleft width. There was also a significant increase in arch width and greater and lesser segments length. All cases were rated as improved by the surgeons in photographic analysis. CONCLUSION The study has quantitatively shown that the modified NAM therapy improved nasal asymmetry by columellar lengthening and effectively molded the maxillary alveolar arch.

Clinical Application of Micro-Implant Anchorage in Initial Orthodontic Retraction

Micro-implant is a device that is temporarily fixed to bone for the purpose of enhancing orthodontic anchorage either by supporting the teeth of the reactive unit or by obviating the need for the reactive unit altogether, and which is subsequently removed after use. The purpose of this study was to evaluate the clinical efficiency of micro-implants in reinforcing anchorage during the initial retraction of anterior teeth, check the rate of initial retraction for 8 weeks, and assess the stability of micro-implants during this period. Eighteen micro-implants were placed (10 in the maxilla and 8 in the mandible) and immediately loaded with 200-250 g of force using 9-mm closed coil Nitinol springs. The amount of space closure was measured every 2 weeks until the eighth week. Cephalometric measurements were made at the end of the study to evaluate anchor loss, if any. Micro-implant stability was also assessed. The rate of initial retraction in the maxilla at the end of 8 weeks was 1.65 mm/quadrant and 1.51 mm/quadrant in the mandible. The amount of retraction on the left side of the arches was 1.66 mm/quadrant and 1.49 mm/quadrant on the right side. The average initial retraction for both arches per month was 0.78 mm. An anchor loss of 0.1 mm (0.06%) was observed in the maxilla while no mandibular anchor loss was recorded. The rate of initial retraction observed in the maxilla was more than that achieved in the mandible. Initial retraction was also more on the left side of the arches. There was no anchor loss in the mandible. The micro-implant-reinforced anchorage was helpful in minimizing anchor loss and accepted heavy traction forces but did not bring about a faster rate of retraction.

A novel method of comparison of two-dimensional measurement with three-dimensional cone-beam computed tomography for measuring the maxillary casts of cleft lip and palate patients

Aim and Objective: The aim of the present study was to explore a novel two-dimensional (2D) software technique and investigate the relationship between corresponding 2D and three-dimensional (3D) measurements on maxillary plaster casts of infants up to 6 months of age born with complete unilateral and bilateral cleft lip and palate (BCLP). Materials and Methods: Twenty-five series of plaster casts were made of infants with complete unilateral and BCLP up to 6 months and were subjected to photographs followed by digitization for 2D software (MAKHTER) measurements and additionally to cone-beam computed tomography scanner for 3D digitization and measurement. The corresponding 2D and 3D measurements of the selected linear distances, curve lengths, and surface areas were carried out, and the efficacy of our 2D software was assessed and compared with 3D using linear regression. Results and Conclusion: Our innovative 2D technique was found to be much reliable and effective as the values for different landmarks were found to be close with 3D. However, 3D method presented good accuracy error (0.8%) on measuring geometric objects. There were no statistically significant differences (P > 5%) noted for different methods (2D and 3D) for almost all the distances analyzed. Thus, 2D software could be used as reliable alternate tool for 3D measurements, and additionally, 3D values could be predicted using Deming regression analysis from 2D measurements values.

Comparative evaluation of load-deflection property of different brands of nickel-titanium archwires

Context: The tooth alignment and leveling constitute the preliminary clinical phase of any orthodontic procedure with fixed appliances. It has been accepted in orthodontics the principle that light and continuous forces would be desirable for physiologic and controlled tooth movement. For this purpose, it has been suggested that nickel-titanium (NiTi) archwires which offer a force-bending curve with a defined baseline and a larger activation range should be used Aims: The aim of this study was to evaluate and compare the force versus deflection properties of different brands of NiTi wires available in market. Settings and Design: Null hypothesis. There is no difference in force-deflection properties between different brands of same dimension NiTi archwires available in market. A cross-sectional study design was planned. Subjects and Methods: Different companies were identified producing their own version or marketing NiTi archwires of the following sizes: 0.016 inch round and 0.016 × 0.022 inch rectangular were selected because all companies produced or marketed these particular sizes, and in addition, these were selected because these wire sizes are commonly used clinically. The three-point bend test was utilized to test the various wires in accordance with the ISO 15841 standard for orthodontic wires with the exception that the bottom support span was 16 mm rather than 10 mm due to fixture limitations. Statistical Analysis Used: Data obtained from different brands of wires available in the Indian market Ormco, American Orthodontics, Ortho Organizers, Rocky Mountain Orthodontics 3M and MO which are manufactured in U.S.A,While as Natural, Orthomatix, JJ Orthodontics, Koden, Gdc, Rabbit force, and Optima are manufactered in china. and size 0.016 inch round wire and 0.16x0.022 inch rectangular wires were compared using ANOVA test.Statistical analysis was performed using SPSS 2.1. Results: In this study, the data show that minimum force during activation of 0.016 inch round wire at 1 mm was 95 ± 10 g whereas maximum was 165 ± 10 g with a difference of 70 ± 20 g. Whereas at 3 mm activation, minimum force generated was 150 ± 10 g and maximum was 225 ± 10 g with a difference of 75 ± 20 g. In 0.016 × 0.022 inch rectangular wire, minimum activation force at 1 mm deflection was 210 ± 10, whereas maximum was 340 ± 10 with a difference of 130 ± 20 g. For deactivation, the minimum force for 0.016 wire at 1 mm deflection was 40 ± 10, whereas maximum force was 125 ± 10 with a difference of 85 ± 20 g, and for the 0.016 × 0.022 wire, the minimum load at 1 mm deflection was 150 ± 10 g, whereas the maximum was 295 ± 10 g with a difference of 145 ± 20 g. The deactivation force in majority of brands (8) at 1 mm deflection was <80 g whereas at 3 mm, majority brands have force levels >150–195 g. The deactivation force at 3 mm deflection in five brands was between 235 and 335 and five other brands between 335 and 445 whereas at 1 mm, deflection majority of brands was between 170 and 200 g. Conclusion: From this data, a comparative evaluation shows that there is a huge difference in force-deflection properties of same dimension wire from different brands, which means that its making the orthodontic treatment more indeterminate; some wires have shown less and some have shown more force.Wires of the same materials, dimensions, but from different manufacturers do not always have the same mechanical properties. There are significant differences in the activation and deactivation forces among the different manufacturers of NiTi archwires. Improvements should be made in the standardization of the manufacturing testing process of NiTi archwires to provide orthodontists with NiTi archwires that have consistent mechanical properties despite the manufacturing brand that produces them.

Evaluation of Lingual Orthodontic appliances

Due to increasing popularity of lingual orthodontics in recent years, various lingual systems have been developed. In orthodontics Finite Element Method (FEM) has been used to study various types of tooth movement. Although FEM was extensively used for evaluating the biomechanical effects of labial orthodontic forces, research on lingual system is still limited. The purpose of this study is to evaluate the efficacy of two different lingual bracket systems using FEM. FEM of maxilla which included six upper anterior teeth, periodontal ligament has been created. Six upper anterior teeth were digitally arranged in final position using a new computerized method. CAD models of six upper anterior brackets of 7 generation and Lingual matrix have also been created and attached onto the digital model at appropriate heights. Various orthodontic movements were simulated and force applied distal to the canine bracket. Deformation, stress on teeth, bone and periodontal ligament were studied and compared between the two different lingual systems. Deformation was less with lingual matrix brackets than 7 generation brackets when subjected to intrusive, retractive and combined forces. More stresses were generated on the teeth, bone and PDL in lingual matrix brackets than 7 generation brackets when subjected to forces. It was found that tooth movements are more efficient and precise in lingual matrix brackets than prefabricated 7 generation brackets.

Prenatal and postnatal growth: An ultrasound and clinical investigation

Background: Understanding facial development requires sound knowledge of growth at different stages. Although studies in the past have established the relationship between prenatal and postnatal growth, little research has been done using noninvasive ultrasound. The purpose of this study is to evaluate correlation between prenatal and postnatal growths using ultrasound as a fetal growth assessment tool. Study Settings: It is a hospital-based study where prenatal growth is measured at different intervals of gestational period and compared with the growth at birth. Materials and Methods: Ten subjects with normal pregnancy were studied using ultrasound. Cephalocaudal growth gradient, body proportions of the fetus were assessed and compared at different stages. Growth was also evaluated at birth and compared with the predicted growth. Results: The growth rate of estimated fetal weight is at maximum between the 28th and 32nd week of the fetal life (P ≤ 0.001). The growth rate of head circumference, occipitofrontal diameter, and femur length is maximum between the 20th and 28th week of the fetal life (P < 0.001). Cephalocaudal growth gradient decreases with increased age of the fetus. Conclusions: Prenatal growth is correlated with postnatal growth. Ultrasound can be used as a tool for the measurement and prediction of prenatal and postnatal growths.