Aleš Čelar

A prospective randomized split-mouth study on pain experience during chairside archwire manipulation in self-ligating and conventional brackets

OBJECTIVE To investigate patient discomfort during archwire engagement and disengagement in patients treated with self-ligating and conventional brackets using a split-mouth design. MATERIALS AND METHODS Eighteen consecutive patients (15 female, 3 male; age: 22.2 ± 6.4 years) who requested treatment with fixed orthodontic appliances were randomly assigned for bonding with SmartClip self-ligating brackets on one side of the dentition and conventional standard edgewise brackets on the other. During the course of treatment, patients rated the discomfort experienced during every archwire engagement and disengagement using a numeric rating scale. Results were evaluated for round and rectangular nickel titanium and rectangular stainless steel, titanium molybdenum, and Elgiloy archwires. Patients also rated their overall experience retrospectively for both bracket systems. RESULTS Regardless of archwire type, disengagement was rated as being significantly more painful on the SmartClip side (P  =  .027). For rigid, rectangular archwires, engagement and disengagement were rated as being significantly more painful on the SmartClip side (P  =  .031; P  =  .004). Retrospective ratings favored conventional brackets beyond ratings recorded during treatment. CONCLUSION Engagement and disengagement of rigid rectangular archwires caused more pain with SmartClip self-ligating brackets than with conventional ones. Careful archwire manipulation and patience during full alignment are essential for limiting chairside pain. Low pain levels will help ensure treatment satisfaction and compliance.

Comparison of Japanese and European overbite depth indicator and antero-posterior dysplasia indicator values

This study evaluated cephalometric differences between 113 Japanese (43 males and 70 females, aged 14.1 ± 5 years) and 106 European subjects (36 males and 70 females, aged 13.5 ± 7.3 years) using two compound angular measurements and their single components: the overbite depth indicator (ODI) for the assessment of vertical skeletal relationships and the antero-posterior dysplasia indicator (APDI) for an evaluation of sagittal dysgnathia. Both populations were assigned to groups representing Angle Classes I, II, and III, and an anterior open bite (AOB) group. Two sample t- and Wilcoxon signed-ranks tests were performed (P < 0.05). The ODI values showed no statistically significant differences between the Japanese and European samples. The Japanese sample showed a significantly smaller APDI but only in the Class II group. In the Japanese Class II and III subjects, the malocclusion patterns were more pronounced than those in the Caucasian sample (overbite, overjet, and APDI).

Osseointegration of a subperiosteal anchoring device in the minipig mandible

INTRODUCTION Onplants serve as subperiosteal anchorage in the maxilla to facilitate tooth movement. We determined the applicability of onplants and the process of osseointegration in the mandible of minipigs. METHODS Thirty-six onplants (OnPlants, Nobel Biocare USA, Yorba Linda, Calif) were positioned in 9 adult animals, 2 on each side. At 3, 6, and 12 weeks after surgery, 3 minipigs were killed. Undecalcified ground sections were evaluated histologically and histomorphometrically. RESULTS Nineteen onplants were lost during the observation period. Newly formed bone per tissue volume was 7% +/- 5% (n = 4), 21% +/- 9% (n = 5), and 22% +/- 13% (n = 8) at the 3 observation times. The corresponding percentages of bone-to-implant contact were 15% +/- 22%, 30% +/- 27%, and 44% +/- 35%. The number of bone-to-implant contacts remained stable over time at 1.0 +/- 0.9 contacts per millimeter. The average lengths of bone-to-implant contacts were 0.2 +/- 0.1 mm, 0.3 +/- 0.2 mm, and 0.5 +/- 0.3 mm. CONCLUSIONS These results showed a low survival rate of onplants in the mandible and that the early stage of healing is central to the process of osseointegration. Stable placement is a prerequisite for onplant survival in the mandible.

Geometric morphometric evaluations of a randomized prospective split-mouth study on modes of ligation and reverse-curve mechanics

OBJECTIVES To evaluate tooth position after six and 9 months of orthodontics with conventional brackets on one side of the dentition and ligature-less brackets on the other. SETTING AND SAMPLE POPULATION Orthodontic Division, Vienna Medical University. Twenty patients aged 22.5 ± 5.7 years, symmetrical malocclusion and arch form, no premolar extraction. MATERIAL AND METHODS Prospective split-mouth study, 0.022-inch SmartClip self-ligating brackets assigned randomly to the left or right dentition, conventional 0.018-inch brackets on the other side. 52 dental landmarks, digitized on plaster casts, represented dental arches at baseline (t0), 6 months and 9 months (t1, t2). During t0-t1, we used 0.016 and 0.014 x 0.025 inch superelastic wires, during t1-t2 connected reverse-curve hemiarch wires: 0.017 x 0.025 inch ß-titanium on the ligature-less side, and 0.016 x 0.022 inch Elgiloy multiloop wires on conventional brackets. Morphometric analyses were used to assess differences in dental arch shapes. RESULTS Neither initial alignment nor the reverse-curve phase showed statistically significant differences between ligature-less and conventional brackets in moving teeth. CONCLUSION Morphometric shape analyses corroborated current evidence that self-ligating brackets were no more effective than conventional brackets with steel ligatures after 6-month initial alignment. From months 6-9 treatment with ß-titanium reverse-curve wires on 0.022-inch ligature-less brackets resulted in similar tooth positions as accomplished by Elgiloy multiloop wires on 0.018-inch steel-ligature-tied brackets.

Inter- and intraobserver variability in resonance frequency analysis of palatal implants--a technical note.

PURPOSE To assess inter- and intraobserver variability in wireless resonance frequency analysis (RFA) stability measurements of palatal implants and to evaluate the influence of age, sex, time after implant insertion, and measurement direction on variability. MATERIALS AND METHODS Three observers conducted wireless RFA stability measurements of palatal implants from 16 patients. Measurements were taken in anteroposterior and laterolateral directions and were repeated after 1 hour. RESULTS Data showed a small interobserver variation (1.93) with intraobserver variation (1.77) as its largest component. Time after implantation showed a strong influence (P = .027) on the interobserver variation. CONCLUSIONS The tested wireless RFA device can be considered a reliable instrument for measuring the stability of palatal implants. Multiple readings and observers could further improve measurement reliability.