Efficacy of the Nance appliance as an anchorage-reinforcement method.

INTRODUCTION: The Nance appliance is widely considered to be an efficient method of anchorage reinforcement; however, much of the perceived advantage is based on clinical judgment. The aim of this study was to assess the amounts of anchorage loss and desired tooth movement associated with the Nance appliance. METHODS: The mandibular arches of 7 beagle dogs were used. The first and third premolars were extracted. Reference miniscrews were placed at the first premolar sites as stable references to measure the amounts of anchorage loss and desired tooth movement. Four beagles were fitted with custom-made Nance appliances on the fourth premolars and orthodontic bands on the second premolars (Nance group). Three beagles were fitted with orthodontic bands on the second and fourth premolars with no anchorage reinforcement (control group). The second premolars were retracted over 15 weeks in both groups. The amounts of second premolar movement (desired tooth movement) and fourth premolar movement (anchorage loss) were recorded at 5, 10, and 15 weeks. The percentages of desired tooth movement and anchorage loss to the total space closure were calculated. RESULTS: The mean desired tooth movement was significantly more in the Nance group than in the control group at 10 weeks (P <0.05) but was not significantly different at 5 and 15 weeks. The mean percentages of anchorage loss to the total space closure at 15 weeks were 45.7% in the control group and 28.8% in the Nance group. The Nance group had 16.9% less anchorage loss and 16.6% more desired tooth movement than did the control group at 15 weeks (P <0.05). Most of the anchorage loss (80%) in the Nance group occurred during the first 10 weeks. CONCLUSIONS: The Nance appliance did not provide absolute anchorage, but there was significantly less anchorage loss with it than in the control group. The majority of anchorage loss occurred during the first 10 weeks in the Nance group.

Pain and anxiety following the placement of dental implants.

PURPOSE: This study investigated pain experience and anxiety following dental implant placement using questionnaires and salivary cortisol measurements. MATERIALS AND METHODS: Patients about to undergo implant placement were instructed to keep recovery diaries to assess pain experience (limitation of activities, postoperative symptoms) and to record average pain, worst pain, and interference with daily activities on a visual analog scale (VAS). To assess anxiety, patients completed the Spielberger self-evaluation questionnaire and collected salivary samples to measure cortisol levels. Saliva was collected 1 week before surgery, the day of surgery, and 3 and 6 days postoperatively. A repeated-measure analysis of variance was used to analyze pain and anxiety data. RESULTS: Eighteen patients (12 women and 6 men) who received 30 implants were recruited for the study. Following implant placement, most patients reported mild to moderate interference with daily activities and postoperative symptoms. No patient reported high levels of any symptom. Average pain experience decreased significantly with time (F = 6.17; P < .001), from a VAS score of 24/100 on day 1 to 12 on day 3 and 9 on day 6. Worst pain (F = 7.84; P < .001) and limitation of daily activities (F= 6.26; P < .001) were also highest on the first postoperative day; they also decreased to about half the maximum level by the second or third day. State anxiety, as evaluated by the Spielberger self-evaluation scale, was highest on the day of surgery. The salivary cortisol level did not validate this, as it did not differ with the time of collection (F = 2.22; P = .075). CONCLUSIONS: Patient self-assessment indicates that implant placement is a mild to moderately painful and anxiety-provoking procedure. Some limitation of daily activities and symptoms are expected to occur, particularly during the first 3 postoperative days.