A study on the prevalence of dental anomalies in Korean dental-patients / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to investigate the prevalence of dental anomalies in outpatient clinics. METHODS: The subjects of this study were 3,133 patients who visited the clinic between January 2009 and June 2011. The dental records and panoramic films of the patients and detection of supernumerary, missing, and impacted teeth, transposition, and peg lateralis were reviewed. The results were analyzed according to gender and types and locations of dental anomalies. RESULTS: Among the patients, 362 had dental anomalies, with a prevalence rate of 11.55%. Congenital missing teeth (5.71%) ranked first in the categories, and impacted teeth (3.09%) ranked second. The percentage of patients having supernumerary teeth, peg lateralis, and dislocated teeth were 1.79%, 1.66%, and 0.45%, respectively. CONCLUSIONS: Congenital missing teeth and impacted teeth are, respectively, the first and second most common dental anomalies in Korean dental patients.

Modified laser etching technique of enamel for bracket bonding / 대한치과교정학회지

OBJECTIVE: Many studies have carried out research on comparisons between laser etching and conventional etching systems to investigate methods of reinforcing shear bond strength. The purposes of this study were to assess the efficiency of bonding with erbium, chromium doped: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser etching combined with the conventional etching technique. METHODS: Sixty-four sound premolars, extracted for orthodontic purposes, were randomly divided into 4 groups and treated in the following manner. First group, conventional etching of 37% phosphoric acid for 15 seconds (control); second group, 1.5 W laser etching for 10 seconds followed by conventional etching; third group, conventional etching followed by 1.5 W laser etching; fourth group, 1.5 W laser etching for 15 seconds only. We assessed the shear bond strength, the surface characteristics, and the adhesive remnant index scores between all groups. RESULTS: Experimental groups showed higher shear bond strength than the control group. But no statistically significant differences were found between the second and third groups. Adhesive remnant scores were compared with the Kruskal-Wallis test, and no statistically significant differences were found between all groups. CONCLUSIONS: To obtain maximum shear bonding strength, a combined technique of Er,Cr:YSGG and 37% phosphoric acid is useful even though it may be inconvenient.

The therapeutic effect of silver nanocrystalline ointment on TMJ capsulitis

The silver nanocrystalline is widely used for biological field because of its biocompatibility and anti-microbial effect. The objective of this study was to evaluate the therapeutic efficacy of the silver nanocrystalline ointment on the temporomandibular joint (TMJ) capsulitis. Total 39 patients were included in this study and all patients were received single topical application of the silver nanocrystalline ointment (group A, n=30) or placebo ointment (group B, n=19). Measured variables were maximum mouth opening (MMO), visual analog scale (VAS) for pain, and VAS for function. In results, we could not assess any therapeutic efficacy of single application in the chronic TMJ capsulitis (p>0.05). However, the single application of silver nanocrystalline ointment showed significant improvement in MMO and VAS for pain compared to placebo effect in the acute TMJ capsulitis (p<0.05). We could not find any complications related to ointment application in both groups. In conclusion, the single application of silver nanocrystalline ointment was effective in improving patient's symptom in acute TMJ capsulitis without any noticing complications.

A study on the perimandibular tissues before and after orthodontic treatment with orthognathic surgery in mandandibular prognathic patients / 대한치과교정학회지

Severe skeletal anteroposterior and vertical discrepancy is difficult to obtain satisfactory result by only orthodontic treatment, and much anteroposterior movement and treatment stability require orthodontic treatment with orthognathic surgery. The treatment goal of mandibular prognathic patients is to promote the function of stomatognathic system including mastication and phonetics, to improve the esthetics of facial profile and to maintain stability. Positional changes of hyoid bone, pharynx and tongue were seen with mandibular movement after orthognathic surgery. This study was performed to observe the changes of perimandibular tissues of orthodontic patients with skeletal mandibular prognathism who treated with orthodontic treatment, and the changes of hyoid bone, pharyx and tongue by relapse or recurrance after before and after orthognathic surgery and retention. The 22 patients who had mandibular prognathism were selected. They treated with orthodontic treatment with sagittal split ramus osteotomy as orthognathic surgery. And lateral cephalomeric radiography were taken 3 times: pre-surgery (T1), immediate post-surgery (T2) and 2 years after retention (T3). The results were as follows : 1. The hyoid bone returned back after clockwise rotation to maxilla and occlusal plane during retention (p<0.01). 2. The hyoid bone moved posterior-inferiorly by mandibular surgery and returned back anterior-superior after retention (p<0.01). 3. The changes of pharyngeal depth showed a little decrease at upper area in post-surgery, but it was not a significant difference generally through before, after and retention. 4. In relating to tongue base, the angle of tongue base was decreased and the dorsal area of tongue base moved to inferior-posterior direction and to superior direction again after retention (p<0.01). 5. Related to the thickness of upper and lower lip, the thickness of upper lip decreased after surgery, and the soft tissues below lower lip increased after surgery and decreased after retention.