Magnetic resonance imaging assessment of articular disc position in temporomandibular disorder subjects with various bite registrations.

Objective: This study aimed to evaluate the validity and reliability of three bite registrations on articular disc position in temporomandibular disorder patients using magnetic resonance imaging (MRI). Materials and Methods: Fifteen clinically symptomatic and orthodontically untreated temporomandibular disorder patients within the age range of 17-40 years (mean age: 28.5 years) were examined. Each patient was subjected to three bite registrations, namely maximum intercuspation, initial contact bite and Roth power centric bite, and evaluated with MRI. Results: On the right side, the mean vertical and horizontal measurement values of the point in the most posterior aspect of the posterior band of the articular disc in relation to horizontal reference line (HRL) and vertical reference line (VRL) in the sagittal view in the Roth power centric bite were lesser (2.720 ± 1.239 mm and 2.380 ± 1.185 mm, respectively), in comparison with the other two bites, and on the left side too, it was lesser in the Roth power centric bite (2.293 ± 0.979 mm and 2.360 ± 1.078 mm, respectively), when compared to the other two bites. Statistical analysis also showed the significance of Roth power centric bite over the other two bites. Conclusions: Favourable articular disc positional changes were observed in the Roth power centric bite followed by the initial contact bite and that maximum disc recapture was observed in most patients with the Roth power centric bite rather than in initial contact bite and maximum intercuspation positions. The Roth power centric bite could be assumed to be the ideal method for articulation and fabrication of gnathological splints for treating patients with temporomandibular disorders.

Orthodontic instrument sterilization with microwave irradiation.

OBJECTIVE: This study was designed to evaluate the efficiency of microwave sterilization of orthodontic instruments and molar bands immersed in plain distilled water with and without oral rinse, and to ascertain the minimum time of exposure required to sterilize. MATERIALS AND METHODS: The orthodontic instruments (hinged and nonhinged), molar bands and mouth mirrorsused in the patient 's mouth were selected for the study. The instruments were divided into two groups - Group I with oral rinse-set A (0.01% chlorhexidine gluconate) and set B (0.025% betadine) and Group II (included sets C and D without oral rinse). The instruments of set A, B and C were microwaved at 2,450 MHz, 800 W for 5 min, whereas, set D was microwaved for 10 min at the same above mentioned specifications. The efficacy of sterilization was assessed by stab inoculation of the instruments onto trypticase soya agar plates. The plates were checked for bacterial growth following incubation at 37 °C for 24 h. For sterility control,Geobacillus stearothermophilus (MTCC 1518) was included. RESULTS: No growth was observed in the plates that were inoculated with the microwaved orthodontic instruments of sets A, B and D, whereas scanty bacterial growth was observed in the plates inoculatedwith the microwaved set C instruments. CONCLUSION: Effective sterilization was achieved when the orthodontic instruments and molar bands were immersed in distilled water without oral rinse and microwaved for 10 min as also for those that were immersed in distilled water with oral rinse and microwaved for 5 min.

Solitary median maxillary central incisor: A case report of a rare dental anomaly.

The solitary median maxillary central incisor (SMMCI) syndrome is a rare dental anomaly and has an incidence of 1:50,000 live births. In SMMCI, there is only one central incisor present, and it develops exactly at the midline. SMMCI occurrence has been described with growth hormone deficiency or other structural anomalies in the midline of the body. In this case, the 8-year-old female patient reported a single median maxillary central incisor with missing maxillary and mandibular frena, with apparently no other abnormalities. Early diagnosis and recognition of SMMCI are important for all practicing Orthodontists, as it may be a sign of other severe congenital or developmental abnormalities.

Accelerated osteogenic orthodontics--a case report.

This case report outlines the possibility of rapid orthodontic tooth movement with the use of an accelerated osteogenic technique. A 28-year-old female patient presented with a class I malocclusion, bimaxillary proclination, spacing between the maxillary and mandibular incisors and previous extraction of all four first premolars. Orthodontic treatment from appliance placement to debond took 6 months and 2 weeks.

Construction bite--cornerstone of an efficient functional appliance.

Construction bite is an intermaxillary wax record used to relate mandible to maxilla in the three dimensions of space. It is an indispensable record to correct functional malocclusions like functional retrusion and functional protrusion. This article highlights the basic required dimensions of construction bites used for the fabrication of various functional appliances.