Editorial

Introduction Mandibular retrognathism is considered to be the most important risk factor for upper airway obstruction. Aim This cross-sectional study intended to examine the relationship between craniofacial morphology and the pharyngeal airway space (PAS) in patients with mandibular retrognathism and mandibular prognathism, when compared to normal subjects. The study also analyzed the influence of mandibular morphology on pharyngeal length (PL). Materials And Methods The PAS was assessed in 92 females (age 15-30 years) further divided into three groups - Group 1- normal mandible (76°= SNB =82°; n = 31); Group 2-mandibular retrognathism (SNB <76°; n = 31); Group 3-Mandibular prognathism (SNB >82°; n = 30). All subjects were examined by lateral cephalometry with head position standardized using an inclinometer. Craniocervical angulation, uvula length, thickness and angulation were compared among different groups. Results The results showed no statistically significant difference in the pharyngeal airway between the three groups. Measurements of PL showed statistically significant higher values for retrognathic mandible group than normal and prognathic mandible group. Conclusion There is no significant difference between PAS between patients with mandibular retrognathism, normal mandible and mandibular prognathism. Mandibular retrognathism patients show a significantly higher uvula angulation than patients with mandibular prognathism. Craniocervical angulation showed maximum value in retrognathic mandible group followed by normal and prognathic mandible group respectively. Mean PL for retrognathic mandible patients was significantly higher than prognathic mandible patients.

This article was designed to report the current status of temporomandibular joint disorders (TMDs) and the therapeutic system on the basis of a series of clinical, biomechanical, histological and biochemical studies in our research groups. In particular, we have focused on the association of degenerative changes of articular cartilage in the mandibular condyle and the resultant progressive condylar resorption with mechanical stimuli acting on the condyle during the stomatognathic function. In a clinical aspect, the nature and prevalence of TMDs, association of malocclusion with TMDs, association of condylar position with TMDs, association of craniofacial morphology with TMDs, and influences of TMDs, TMJ-osteoarthritis (TMJ-OA) in particular, were examined. In a biomechanical aspect, the nature of stress distribution in the TMJ from maximum clenching was analyzed with finite element method. In addition, the pattern of stress distribution was examined in association with varying vertical discrepancies of the craniofacial skeleton and friction between the articular disk and condyle. The results demonstrated an induction of large compressive stresses in the anterior and lateral areas on the condyle by the maximum clenching and the subsequent prominent increases in the same areas of the mandibular condyle as the vertical skeletal discrepancy became more prominent. Increase of friction at the articular surface was also indicated as a cause of larger stresses and the relevant disk displacement, which further induced an increase in stresses in the tissues posterior to the disks, indicating an important role of TMJ disks as a stress absorber. In a histological or biological aspect, increase in TMJ loading simulated by vertical skeletal discrepancy, which has already been revealed by the preceding finite element analysis or represented by excessive mouth opening, produced a decrease in the thickness of cartilage layers, an increase in the numbers of chondroblasts and osteoclasts and the subsequent degenerative changes in the condylar cartilage associated with the expression of bone resorption-related factors. In a biochemical or molecular and cellular aspect, excessive mechanical stimuli, irrespective of compressive or tensile stress, induced HA fragmentation, expression of proinflammatory cytokines, an imbalance between matrix metalloproteinases and the tissue inhibitors, all of which are assumed to induce lower resistance to external stimuli and degenerative changes leading to bone and cartilage resorption. Excessive mechanical stimuli also reduced the synthesis of superficial zone protein in chondrocytes, which exerts an important role in the protection of cartilage and bone layers from the degenerative changes. It is also revealed that various cytoskeletal changes induced by mechanical stimuli are transmitted through a stretch-activated or Ca2+ channel. Finally, on the basis of the results from a series of studies, it is demonstrated that optimal intra-articular environment can be achieved by splint therapy, if indicated, followed by occlusal reconstruction with orthodontic approach in patients with myalgia of the masticatory muscles, and TMJ internal derangement or anterior disk displacement with or without reduction. It is thus shown that orthodontic treatment is available for the treatment of TMDs and the long-term stability after treatment.

Objective Improvement in appearance is an important motivation for orthodontic treatment; nevertheless, not all patients with malocclusion seek treatment; therefore, the aim of this study was to compare the psychological state of patients with moderate to severe malocclusion who seek orthodontic treatment with patients who suffer from similar malocclusion but do not seek treatment. Materials And Methods Minnesota multiphasic personality inventory-2 questionnaire which assesses psychological states of people were given to 100 subject with moderate to severe malocclusion who were undergoing orthodontic treatment and 100 subjects with similar malocclusion who did not request orthodontic treatment. All subjects had similar demographic variables. Clinical scales measured by the test included: Hypochondriasis, depression, hysteria, psychopathic deviate, paranoia, psychasthenia, schizophrenia, and hypomania. The questionnaire consisted of 71 questions, and the subjects had to mark “True” or “False” in response. The scores were transformed into T-scores by a trained psychologist. The results were evaluated by independent t-test. Results And Conclusion The results of the test showed that both treated and untreated subjects were in similar psychological state and were psychologically normal; therefore, it is likely that other factors affect patients’ willingness for seeking orthodontic treatment rather than their psychological state.

Aim The purpose of this investigation was to assess and compare the anchorage loss between labial and lingual appliance systems during space closure. Materials And Methods Twenty subjects were part of the study among which 10 subjects (mean age 21 ± 3.6 years) were treated using lingual appliance system (0.018” slot-STb™) and 10 subjects (mean age 19 ± 6.1 years) were treated using labial preadjusted edgewise appliance system (0.018” slot-MBT™). First premolar extractions were performed to enable retraction of anterior teeth. Lateral cephalometric radiographs were taken at two intervals, before starting space closure and after space closure that were connoted as T0 and T1 and were analyzed using the method described by Pancherz to measure anchorage loss. Intraclass correlation coefficient (ICC) was used to evaluate intraexaminer reliability of the measurements. Student’s t-test was performed to verify any statistical significant correlation between the labial and lingual appliance systems. Statistical differences were determined at the 95% confidence level (P < 0.05). Results The results showed that all ICC for lingual and labial group were =0.90 showing good repeatability of the measurements. Mean anchorage loss of 1.238 ± 0.17 mm in lingual appliance system and an anchorage loss of 2.06 ± 0.39 mm occurred with the labial appliance system. On the comparison between the two appliance systems, lingual appliance demonstrated a significantly lesser anchorage loss than did the labial appliance. Interpretation And Conclusion This prospective study concludes with the fact that lingual appliance provided better anchorage control than labial appliance during space closure. Use of lingual appliance could be considered in critical anchorage cases when compared with labial appliance.

Ligation of the severely rotated teeth at the start of the treatment is time consuming and difficult, even with super-elastic archwires. This article describes a quick and easy method of seating an archwires into the bracket slot for initial alignment.

Book Review

Torque control of individual incisors using pre-adjusted edgewise (PAE) appliance is a common clinical challenge. In order to overcome the inherent disadvantages of the PAE appliance in efficiency of torque delivery, the use of light wire auxiliaries for early control of the roots of the instanding tooth in the alignment stage itself has been described using the case report. A case of an 18-year-old female patient with the chief complaint of irregularly placed upper front teeth has been described. Treatment was carried out by extraction of four premolars and the resolution of crowding and the incorporation of light wire auxiliaries with PAE appliance has been described. For the alignment of 42 which was lingually displaced, and to bring it into the arch by bodily displacement rather than labial tipping, a LIght wire auxiliary (Mollenhauer aligning auxiliary) was used in conjunction with PAE appliance. The biomechanical advantages of the procedure have been highlighted. The use of light wire auxiliaries have definite advantages and hence should be a part of our armamentarium to handle such cases. Light wire auxiliaries offer us a biomechanically superior and economical alternative to apply torque forces on incisors.

Skeletal class II malocclusion is best treated by growth modification using the myofunctional appliances or the orthopedic appliances or the combination of the both depending upon the type of malocclusion encountered during the growth period of an individual. Though all myofunctional appliances work on the same principle with few basic differences; the orthodontist has to make a choice among the plethora of the appliances at his disposal. The present article is a case report of class II malocclusion treatment using the Bass appliance for the growth modification, which was followed by fixed appliance for the occlusal detailing.