Periodontal health of palatally displaced canines treated with open or closed surgical technique: a multicenter, randomized controlled trial.

INTRODUCTION: The aim of this study was to investigate differences in the periodontal outcomes of palatally displaced canines (PDC) exposed with either an open or a closed surgical technique. METHODS: A multicenter, randomized controlled trial was undertaken in 3 hospitals in the United Kingdom, involving 2 parallel groups. Patients with unilateral PDC were randomly allocated to receive either an open or a closed surgical exposure. Periodontal health was assessed 3 months after removal of fixed appliances. Parameters measured included clinical attachment levels, recession, alveolar bone levels, and clinical crown height. RESULTS: Data from 62 participants (closed, 29; open, 33) were analyzed. There was no difference between PDC exposed with an open vs a closed surgical technique (mean difference, 0.1 mm; 95% confidence interval [CI], -0.2-0.5). There was, however, a statistical difference in mean attachment loss between the operated and unoperated (contralateral) canines (mean difference, 0.5 mm; 96% CI, 0.4-0.7; P <0.001). Twenty of the 62 subjects had some recession on the palatal aspect of the operated canine, whereas only 4 subjects had some visible root surface on the palatal aspect on the unoperated side (P = 0.001). CONCLUSIONS: There is a periodontal impact when a unilateral PDC is exposed and aligned. This impact is small and unlikely to have clinical relevance in the short term; however, the long-term significance is unknown. When the open and closed techniques were compared, no difference in periodontal health was found.

Does the bracket-ligature combination affect the amount of orthodontic space closure over three months? A randomized controlled trial.

OBJECTIVE: To investigate the effect of bracket-ligature combination on the amount of orthodontic space closure over three months. DESIGN: Randomized clinical trial with three parallel groups. SETTING: A hospital orthodontic department (Chesterfield Royal Hospital, UK). PARTICIPANTS: Forty-five patients requiring upper first premolar extractions. METHODS: Informed consent was obtained and participants were randomly allocated into one of three groups: (1) conventional pre-adjusted edgewise brackets and elastomeric ligatures; (2) conventional pre-adjusted edgewise brackets and Super Slick(®) low friction elastomeric ligatures; (3) Damon 3MX(®) passive self-ligating brackets. Space closure was undertaken on 0·019×0·025-inch stainless steel archwires with nickel-titanium coil springs. Participants were recalled at four weekly intervals. Upper alginate impressions were taken at each visit (maximum three). The primary outcome measure was the mean amount of space closure in a 3-month period. RESULTS: A one-way ANOVA was undertaken [dependent variable: mean space closure (mm); independent variable: group allocation]. The amount of space closure was very similar between the three groups (1 mm per 28 days); however, there was a wide variation in the rate of space closure between individuals. The differences in the amount of space closure over three months between the three groups was very small and non-significant (P = 0·718). CONCLUSION: The hypothesis that reducing friction by modifying the bracket/ligature interface increases the rate of space closure was not supported. The major determinant of orthodontic tooth movement is probably the individual patient response.

No difference in surgical outcomes between open and closed exposure of palatally displaced maxillary canines.

PURPOSE: To investigate differences in surgical outcomes between open and closed exposure for palatally displaced maxillary canines. MATERIALS AND METHODS: This multicenter randomized controlled trial involved 2 parallel groups. The settings were 1 dental teaching hospital in and 2 hospital units near Sheffield, UK. Participants were younger than 20 years, had a unilateral palatally displaced maxillary canine, and provided informed consent. They were randomly allocated to receive the open or the closed surgical procedure. The outcomes were time spent in the operating room and 10-day postoperative patient questionnaire findings. Statistical differences between the 2 techniques were tested using independent t tests for continuous variables and χ(2) tests for frequencies. RESULTS: The final study sample was composed of 71 participants (64% female). There were no differences in the gender ratios (open: 27 female, 13 male; closed; 25 female, 16 male) or mean ages (open: 14.3 yrs; standard deviation [SD], 1.3 yrs; closed: 14.1 yrs; SD, 1.6 yrs) of the 2 groups at the start. The mean operating times for the open and closed techniques were 34.3 minutes (SD, 11.2 min) and 34.3 minutes (SD, 11.9 min), respectively (P = .986). There were no statistically significant differences between the 2 treatment groups for any patient-assessed outcome (P > .05). CONCLUSIONS: There were no differences in the surgical outcomes investigated in this study between open and closed exposure for palatally displaced maxillary canines.

Palatal implants are a good alternative to headgear: a randomized trial.

INTRODUCTION: The objective of this study was to compare the effectiveness of midpalatal implants with that of headgear as methods of supplementing anchorage during orthodontic treatment. This was a randomized, clinical trial at the Chesterfield and North Derbyshire Royal Hospital NHS Trust and the Charles Clifford Dental Hospital, Sheffield, United Kingdom. METHODS: Fifty-one orthodontic patients between the ages of 12 and 39 with absolute anchorage requirements were randomly allocated to receive either a midpalatal implant or headgear to reinforce orthodontic anchorage. The outcome measures of the trial were the surgical and orthodontic success rates of the implants, the number of visits, and the length of treatment time, and the success of treatment as judged by the peer assessment rating (PAR) score reductions and the patients' attitudes to implant placement. RESULTS: The surgical success rate of the implants was 75%, and the orthodontic success rate was more than 90%. Both implants and headgear proved to be effective methods of reinforcing anchorage. The total number of visits was greater in the implant group, but the overall treatment times were almost identical. There were no statistically significant differences between the 2 groups in PAR scores either at the start or the end of treatment, and the percentages of PAR score reductions were almost identical. The patients had no problems accepting midpalatal implants as a method of reinforcing anchorage. CONCLUSIONS: Midpalatal implants are an acceptable technique for reinforcing anchorage in orthodontic patients and a good alternative for patients who do not wish to wear headgear.

Midpalatal implants vs headgear for orthodontic anchorage--a randomized clinical trial: cephalometric results.

INTRODUCTION: The purpose of this study was to compare the clinical effectiveness of the midpalatal implant as a method of reinforcing anchorage during orthodontic treatment with that of conventional extraoral anchorage. This was a prospective, randomized, clinical trial at Chesterfield and North Derbyshire Royal Hospital NHS Trust and the Charles Clifford Dental Hospital, Sheffield, in the United Kingdom. METHODS: Fifty-one orthodontic patients between the ages of 12 and 39, with Class II Division 1 malocclusion and absolute anchorage requirements, were randomly allocated to receive either a midpalatal implant or headgear to reinforce orthodontic anchorage. The main outcome was to compare the mesial movement of the molars and the incisors of the 2 treatment groups between the start and the end of anchorage reinforcement as measured from cephalometric radiographs. RESULTS: The reproducibility of the measuring technique was acceptable. There were significant differences between T1 and T2 in the implant group for the positions of the maxillary central incisor (P <.001), the maxillary molar (P = .009), and the mandibular molar (P <.001). There were significant differences between T1 and T2 in the headgear group for the positions of the mandibular central incisor (P <.045), the maxillary molar (P <.001), and the mandibular molar (P <.001). All skeletal and dental points moved mesially more in the headgear group during treatment than in the implant group. These ranged from an average of 0.5 mm more mesially for the mandibular permanent molar to 1.5 mm more mesially for the maxillary molar and the mandibular base. No treatment changes between the groups were statistically significant. CONCLUSIONS: Midpalatal implants are an acceptable technique for reinforcing anchorage in orthodontic patients.

The effect of stretching on the release of fluoride from fluoridated elastomeric ligatures.

INTRODUCTION: The aim of this in-vitro investigation was to determine whether stretching increases the amount of fluoride released from fluoridated elastomeric ligatures. METHODS: Ten groups of 4 fluoridated elastomeric ligatures stretched over edgewise premolar brackets were compared with 10 groups of 4 ligatures that were not stretched over brackets. Each group was placed in individual polyethylene bottles containing 1 mL of distilled water and maintained at 37 degrees C in an incubator. A polyethylene bottle containing only distilled water and 4 brackets was used as the control. The fluoride content of the samples was determined once a day for 7 days and regularly thereafter up to 196 days. A fluoride-ion selective electrode coupled to an analyzer was used to determine the fluoride content of the solutions. The sample solutions were changed 24 hours before readings to prevent the results from being cumulative. RESULTS: The fluoride-ion release for each of the groups was calculated and expressed as total fluoride release in micrograms of fluoride per day per milliliter per elastomer. During the first month in solution, the stretched fluoridated elastomers released approximately 32 microgF.day/mL and the unstretched speciments released 30 microgF.day/mL. This represents a 7% increase in fluoride release, which was statistically significant (P = .007). Over the entire test period (196 days), the modules stretched over the brackets released about 13% more fluoride. This was also a statistically significant difference (P = .001). CONCLUSIONS: Stretching increases the concentration and amount of fluoride released from fluoridated elastomeric ligatures.