Chronodentistry through orthodontic perspective: A literature review.

The human body possesses a unique set of machinery called the molecular/biological clocks that function on a regular 24-h basis forming a circadian rhythm (CR). This aids in coordinating the human biological system with ever-changing environmental conditions, thereby maintaining a balance in its functioning. The central/core component of this system is known to be in the suprachiasmatic nucleus of the hypothalamus with a few aides in the periphery. The periodontal ligament in humans, being one of the dynamic oral tissues, has been shown to exhibit this self-sustained, innate oscillatory behavior that has gained significant attention from dental surgeons. Though substantial evidence regarding its precise role in maintaining circadian periodicity is still unclear, its indispensable role in dentofacial functioning cannot be denied. This review is an attempt in bringing to light the possible role of circadian periodicity in the functioning of oral tissues in the field of orthodontics with a special focus on its role in bone remodeling, orthodontic tooth movement, orthopedic and functional appliances, pain management, and their clinical implications. This could provide a better understanding of the various physiologic and pathologic processes and help us refine our approach toward orthodontic diagnosis and therapeutics. This review would therefore serve as an overview, opening more avenues for further research on this topic that can greatly help the orthodontic fraternity.

Safe sites for buccal shelf bone screw placement in various skeletal malocclusions: A CBCT study.

INTRODUCTION: The mandibular buccal shelf area is an extra-alveolar anchorage site that has high quality and quantity of bone, provides biomechanical benefits and has low failure rates. It is essential to place the implant in the region of bone with optimal thickness. The aim of this study was to determine the suitable site of the mandibular buccal shelf for bone screw insertion at 90 degrees and 30 degrees angles of insertion and various heights, angulations, areas of the buccal shelf in prognathic and retrognathic mandibles, and vertical and horizontal growth patterns. METHODS: In this retrospective study, we evaluated the cone-beam computed tomography (CBCT) images of 48 patients in the age range of 18-30 years, divided into four groups. Seven sectional sites were examined at 3, 5, and 7 mm from the alveolar crest at 90 degrees and 30 degrees. The angulation and area of the buccal shelf were examined. RESULTS: Cortical bone thickness increased distally from the first to the second molar in all four groups. CONCLUSIONS: The preferred site for buccal shelf implant placement was distal to the mandibular second molar. The maximum amount of cortical bone was observed distal to the second molar, 7 mm vertically from the alveolar crest, when the buccal shelf implant was placed at 30 degrees angulation to the long axis of the tooth.

Use of pulp tissue of deciduous teeth for gender determination - A comparative molecular analysis study.

Aim: The present study aimed to evaluate the effectiveness of pulp tissue collected from deciduous teeth for the determination of gender using polymerase chain reaction (PCR). Materials and Methods: 140 extracted deciduous teeth were selected. The control group comprised 20 teeth that were subjected to DNA analysis immediately. Whereas Group I and Group II consisted of 60 teeth which were stored in the open environment and salt water, respectively, for a period of 3, 9, and 15 months. DNA was isolated and quantified followed by the amplification of X and Y chromosomes by PCR and compared with the actual gender of the child. The data were analysed using the Shapiro-Wilk test, the independent sample t-test, paired t-test, and the Chi-square test. Result: The PCR analysis results of Group I showed a more correct interpretation of gender as compared to Group II on storage for a period of 15 months. The PCR analysis results of the Control group showed a 100% accuracy rate as compared to the samples in Groups I and II. Conclusions: Gender could be effectively determined from the samples evaluated immediately after extraction. But the period of storage and the method of storage conditions affected the quality of isolated DNA and thus decreased the ability of gender determination.

Comparative evaluation of the effects of bimaxillary and mandibular setback surgery on pharyngeal airway space and hyoid bone position in skeletal class III patients.

Background: To compare the effects of bimaxillary surgery ( Maxillary advancement and mandibular setback) and mandibular setback surgery (Bilateral Sagittal Split Osteotomy) on the pharyngeal airway space (PAS) and the hyoid bone position in a skeletal class III patients. Material and Methods: Thirty four subjects (21 males, 13 females, mean age 26.5 ± 8 years) with skeletal class III pattern (ANB angle of -2° to -6°) were divided into two groups of equal sizes. Group A consisted of 17 individuals who underwent Bilateral Sagittal Split Osteotomy (BSSO)and Group B consisted of 17 individuals who underwent bimaxillary surgery. In both the group, lateral cephalograms were taken, traced and analyzed for the specified parameters at 3 intervals, pre treatment (C1), post surgical (C2), and post orthodontic treatment (C3). Changes in PAS was evaluated at 3 levels i.e, nasopharynx (Upper PAS), oropharynx (Middle PAS) and hypopharynx (Lower PAS). Changes in hyoid bone position were evaluated in anteroposterior and vertical direction at all the 3 intervals. Results: There was a significant constriction of airway at oropharyngeal and hypo-pharyngeal level at C2 and C3 in both the groups. However, the reduction at the oropharyngeal airway was greater in group A. In group B, there was significant increase in the airway at the level of nasopharynx, Hyoid bone was positioned more posteriorly post-surgery in group A which did not return to its original position post treatment. In group B hyoid bone was positioned postero-inferiorly post surgically which came back to its original position by the end of orthodontic treatment. Conclusions: Patients undergoing bimaxillary surgery showed a significant increase in the airway at the level of nasopharynx. Hyoid bone returned to its original position by the end of orthodontic treatment in the bimaxillary surgery group. This study suggested that while treating a skeletal class III malocclusion it is advised to perform maxillary advancements along with mandibular setback surgery. Key words:Bimaxillary surgery, Hyoid bone, Bilateral Sagittal Split Osteotomy, Pharyngeal airway space.

Knowledge, attitude and practice on exposure to Bisphenol A among dental surgeons in Southern India.

BACKGROUND: Bisphenol A (BPA) is a product in the manufacture of Bis-GMA, which is commonly used in dentistry, and is known to have a number of adverse effects. OBJECTIVES: The aim of this study is to evaluate to assess the knowledge, attitude and practice based on exposure and handling of BPA containing materials among dental surgeons for better understanding about the level of care rendered to the patients. MATERIAL AND METHODS: A questionnaire survey was conducted on 400 dental surgeons in Southern India. The questionnaire consisted of 20 objective type questions out of which ten questions assessed knowledge and five questions assessed the attitude and five questions to understand the practice related measures taken by the dentist. The data collected were analysed using SPSS version 23. RESULTS: A total of 402 responses were collected for this online questionnaire survey over a period of 2 months. It was found that females showed higher knowledge and attitude towards exposure to BPA which was statistically significant when compared to males. It showed that dentists with more than 20 years of practice had a higher level of knowledge. Though most of the groups agreed fairly on safety practice to be undertaken related to BPA exposure in their clinics, the ones with experience more than 20 years displayed the least positive attitude and dentists with 6-10 years of practice had the least positive behaviour among all. CONCLUSIONS: In spite of having a good knowledge regarding the harmful effects of BPA, dental surgeons are not very cautious while using materials containing them on a regular basis. Therefore, there is a need to enhance the awareness with the help of Continuing Dental Education programs or proper instructions on the packaging.

Radiographic and histochemical assessment of root resorption during canine retraction through piezocision site.

Introduction: The number of adult patients seeking orthodontics treatment has increased drastically. There is increased need for faster tooth movement and good esthetics. Piezocision is one of the methods used for accelerating the rate of tooth movement. Aims and Objectives: To assess the amount of root resorption after retraction of canine through piezocision site and compare it with that of recently extracted site using cone-beam computed tomography (CBCT) and assessment of dentin sialoprotein (DSP) levels in gingival crevicular fluid (GCF). Materials and Methods: A split mouth design was used in 15 patients who were undergoing first orthodontic treatment with premolar extractions. Randomly one of the sides was chosen as control (Group I) and the other side underwent piezocision procedure (Group II). 0.022 × 0.028'' MBT system was used with 0.017 × 0.025 SS wire for canine retraction using 150 grams of force. GCF samples were collected from mesio-buccal and disto-buccal of the canine with micropipette at baseline (TO) and day 90(T1) to detect the levels of DSP and the root resorption was measured using CBCT. Results: Statistically significant amount of root resorption was observed after retraction in both the groups. DSP levels were increased in both the groups, though little higher in Group II when compared to group I. Conclusion: DSP level was increased on the piezocision side but it was statistically insignificant which suggests the amount of root resorption on both the sides is similar.

Assessment of dentofacial widths in adults with anterior open bite.

CONTEXT: Anterior open bite is a complex condition involving a combination of various dental and skeletal components in three dimensions. The data on the differences and changes in the transverse relation in individuals with anterior open bite are limited. AIMS: To assess the dental arch widths in individuals with anterior open bite using study casts and facial widths using frontal cephalogram and to compare these widths with that of individuals without anterior open bite. MATERIALS AND METHODS: Eighty adults [40 with and 40 without anterior open bite, mean (standard deviation) age = 20.68 years] were selected. The study group was divided into skeletal (n = 19) and dental (n = 21) open bite groups according to Jarabak's ratio. Posteroanterior cephalograms and study casts were analyzed. RESULTS: The mean width of zygomatic arch (112.18 mm) and condylar region (100.55 mm) in the control group was significantly higher (P < 0.05). The mean gonial width in the skeletal open bite group (81.143 mm) was significantly (P < 0.05) lesser than the dental open bite group (84.842). The maxillary intercanine width for the skeletal open bite group (36.48 mm) was significantly (P < 0.01) higher than that of the dental open bite group (34.26 mm). CONCLUSION: A transverse deficiency was seen in in the zygomatic and condylar regions in adults with anterior open bite. Individuals with a skeletal open bite showed a narrow gonial and wider maxillary intercanine width compared with individuals with dental open bite.

Erratum to: Nasal Profile Changes Following Anterior Maxillary Segmental Osteotomy: A Lateral Cephalometric Study.

[This corrects the article DOI: 10.1007/s12663-015-0797-y.].

Nasal Profile Changes Following Anterior Maxillary Segmental Osteotomy: A Lateral Cephalometric Study.

PURPOSE: Orthognathic surgery in reference to the maxilla attempts to correct underlying skeletal deformities and improve function. Consequently it has the potential to significantly alter the central esthetic unit of the face, the nasolabial region. In order to evaluate the nasal morphological changes which would result following anterior maxillary segmental osteotomy (superior and posterior repositioning); four angles namely, nasolabial, nasal tip projection, columellar labial and supra tip break angle were evaluated. METHOD AND MATERIALS: In ten selected subjects who have undergone anterior maxillary segmental osteotomy with superior and posterior repositioning, pre (T1) and post operative (T2) lateral cephalometric parameters pertaining to the four angles were analysed using Wilcoxon signed rank test. RESULTS: A significant increase in nasolabial angle and mild changes in nasal tip projection, columellar labial angle and supra tip break angle were observed. CONCLUSION: The results of this study emphasize the need for the pre surgical evaluation of nasal morphology in every individual planned for anterior maxillary segmental osteotomy.

Anomalous twin circumflex artery in a 47-year-old Indian female.

Anomalous origin of circumflex coronary is not an uncommon finding. However, dual origin of circumflex artery is a rare anomaly. An extensive literature search indicates that there have been only three such prior reports. We report the first such case from the Indian subcontinent. This was diagnosed by conventional angiography and CT angiography.

Enzymatic evaluation of gingival crevicular fluid in cleft palate patients during orthodontic treatment: A clinico-biochemical study.

BACKGROUND: Therapeutic goal in patients with cleft lip and palate is esthetics and long-term health of the stomatognathic system. Patients with cleft lip and palate routinely require extensive and prolonged orthodontic treatment. The osseous structures are absent or poorly developed in the osseous clefts and may be traumatized in the course of orthodontic therapy; hence require constant monitoring during orthodontic treatment. The aim of the study was to evaluate the tissue response of cleft palate patients by quantitative analysis of enzyme activity during orthodontic treatment and assess any difference in the tissue response with that of noncleft patients undergoing orthodontic treatment. MATERIALS AND METHODS: 20 patients requiring orthodontic treatment agedbetween 15 to 25 years were included to participate in the studyof which ten were cleft palate patients (group I) and ten noncleft patients (group II). The GCF samples were collected at incisor and molar sites during orthodontic treatment on days as per the study design in both the groups. The GCF enzymatic levels were estimated and compared. RESULTS: Both groups showed significant increased enzyme activity at the incisor site compared to molar site corresponding to the phases of tooth movement. CONCLUSION: There was significant difference in enzyme activity between the incisor adjacent to the cleft site and molar site. There was no difference in the tissue response between cleft palate patients and noncleft patients during orthodontic treatment.

Large free-floating left atrial thrombus with normal mitral valve.

Left atrial thrombus in the presence of diseased mitral valve and atrial fibrillation is a well known entity. But it is very rare to occur in the presence of normal mitral valve apparatus. We report the case of a 36 year old female who presented with left atrial ball valve thrombus and normal mitral valve apparatus and underwent surgery. This patient with gangrene of right lower limb came for cardiac evaluation. She had infarct in left middle cerebral artery territory- ten months prior to this admission and was on treatment for infertility. She had atrial fibrillation. Emergency surgery to remove the thrombus should be considered given its potential life threatening embolic nature.

An echocardiographic assessment of cardiovascular hemodynamics in patients with large pleural effusion.

BACKGROUND: The close relationship between pleural space and pericardial space and the dependence of their pressure kinetics are well known. This study evaluates the effects of increased intra pleural pressure due to pleural effusion on cardiovascular system. METHODS: Forty patients above the age of 12 who had massive unilateral/bilateral pleural effusion due to non-cardiac etiology were included in the study. Therapeutic thoracocentesis was done for massive pleural effusion. The echocardiographic parameters measured before and after thoracocentesis were compared. RESULTS: Mean age of the patients 46.6 years. Out of 40 patients 8 were females (20%). 7 patients had right atrial collapse on echo. 85% of patients had significant flow velocity changes across both tricuspid valve and mitral valve during phases of respiration.11 patients (47.82%) had IVC compressibility of <50% during inspiration. Mean flow velocity respiratory variations across tricuspid valve before thoracocentesis and after thoracocentesis E 45.04 ± 10.3,32 ± 11.3% (p value <0.001), A 53.71 ± 28%, 32.08 ± 12.5% (p < 0.001) across mitral valve E 32.30 ± 12%, 19.78 ± 7.8% (p < 0.001), A 26 ± 11.2%, 21 ± 9.3% (p 0.006) across pulmonary artery 42.63 ± 31.3%, 17.70 ± 6.2% (p < 0.001), across aorta 21.57 ± 11.4%, 14.08 ± 7.6% (p < 0.001). CONCLUSION: Large pleural effusion has a potential to cause adverse impact on the cardiovascular hemodynamics, which could manifest as tamponade physiology. Altered cardiac hemodynamics could be an important contributor in the mechanism of dyspnea in patients with large pleural effusion.

Orthodontics-surgical combination therapy for Class III skeletal malocclusion.

The correction of skeletal Class III malocclusion with severe mandibular prognathism in an adult individual requires surgical and Othodontic combination therapy. The inter disciplinary approach is the treatment of choice in most of the skeletal malocclusions. A case report of an adult individual with Class III malocclusion, having mandibular excess in sagittal and vertical plane and treated with orthodontics,, bilateral sagittal split osteotomy and Le - Forte I osteotomy for the correction of skeletal, dental and soft tissue discrepancies is herewith presented. The surgical-orthodontic combination therapy has resulted in near-normal skeletal, dental and soft tissue relationship, with marked improvement in the facial esthetics in turn, has helped the patient to improve the self-confidence level.

Standards of facial esthetics: an anthropometric study.

AIM: Anthropometry is an art and science used extensively for measuring the soft tissue proportions. While it is true that error is found in measurements of this kind, a great many trends of growth and development and therapy changes can be recorded with a significant degree of accuracy. OBJECTIVE: Facial proportion varies among the different ethnic groups and today, most of the available studies are done on western population. Hence an Anthropometric study was conducted in the local population. MATERIALS AND METHODS: The study was carried out with the aim of measuring the facial soft tissue proportion in the local population using anthropometry. Study was done using 100 subjects (50 males and 50 females) with Class I skeletal relationship and pleasing profile. Using standard anthropometric landmarks the various anthropometric measurements and facial proportional indices were determined (both horizontal and vertical) and were compared with that for North American Caucasians. RESULTS: The statistical analysis revealed significant differences in the facial proportion between the two populations.

Evaluation of buccolingual inclination of posterior teeth in different facial patterns using computed tomography.

BACKGROUND AND OBJECTIVE: Buccolingual inclination of teeth is an essential factor in establishing good occlusion. The objective of this study was to evaluate the buccolingual inclination of molar teeth in different vertical skeletal patterns by using computed tomography scans. MATERIALS AND METHODS: Coronal section of the jaws obtained from computed tomograms were used to measure the buccolingual inclination of the long axis of the molars relative to their skeletal base. Forty male adult individuals with class I dental occlusion were selected. They were classified as short (Group 1), average (Group II), and long faced (Group III) as per their skeletal patterns measured by GoGn-SN, FH-MP, Y-axis and facial height index in cephalograms. STATISTICAL ANALYSIS: ANOVA and Tukey HSD tests were applied to calculate if there were any significant differences in the mean molar inclination between the groups. Pearson's coefficients of correlation were calculated between the facial parameters and tooth inclination. RESULTS: The differences in the mean molar inclination between the short, average, and long faced groups is significant for mandibular 1 st and 2 nd molars and maxillary 2 nd molars. CONCLUSION: Variations in mean molar inclination values are observed between short, average, and long faced groups.

Interceptive Orthodontics and Growth Modification Therapy with Fixed Functional Appliance: A Case Report.

A 12-year-old female patient presented with proclined upper anteriors on a class II skeletal base, a retrognathic mandible and high maxillary- mandibular plane angle. Lower first molars were mesially tipped and lower second premolars were impacted. Treatment plan included uprighting and distalising the lower molars followed by growth modulation with Jasper Jumper to correct the mandibular retrognathism. Final finishing and detailing of occlusion was carried out through 0.022" MBT prescription preadjusted edgewise appliance therapy.

Masseter muscle thickness in different skeletal morphology: an ultrasonographic study.

BACKGROUND: The thickness of the masseter muscle during relaxation and contraction states was measured by ultrasonography. Subjects were classified according to their sagittal skeletal relationships. The association between muscle thickness and facial morphology was studied. CONTEXT: Masseter muscle thickness influences the skeletal patterns. AIM: To measure and compare the thickness of the masseter muscle in individuals with skeletal class I occlusion and skeletal class II malocclusions and to correlate its relationship with craniofacial morphology. SETTINGS AND DESIGN: The study was conducted in a hospital setup and was designed to study the thickness of the masseter muscle in different skeletal morphologies. MATERIALS AND METHODS: Seventy two individuals between the ages of 18 and 25 years were divided into Group I, Group IIA and Group IIB according to their skeletal relationships. Masseter muscle thickness was measured by ultrasonography. Eight linear and six angular cephalometric measurements were assessed. STATISTICAL ANALYSIS USED: Analysis of variance and Pearson's correlation analysis. RESULTS: There was a statistically significant difference in muscle thickness between subjects of different skeletal patterns. Significant positive correlation between masseter muscle thickness and posterior total face height, jarabak ratio, ramus height, mandibular length and significant negative correlations with mandibular plane angle, gonial angle and PP-MP angle were observed. CONCLUSION: This study indicates the strong association between the masseter muscle and skeletal morphology.