Characteristics of newly-formed cementum following emdogain application

Periodontal regenerative techniques have been proposed; however, the outcomes remain debatable. The present investigation assessed the regenerated cementum following enamel matrix derivative application in dehiscence-type defects. Buccal osseous dehiscences were surgically created on the maxillary cuspid, and the second and fourth premolars in five female beagle dogs. The treatment group （n=15 sites） received the enamel matrix derived application, whereas the control groups （n=15） did not. The dogs were sacrificed 4 months following treatment and the specimens were histologically and histometrically examined. The newly formed cementum was uneven in thickness and mineralization, overlapped the old cementum and exhibited functional orientation, cementocyte lacunae and collagen fibril bundles. Most of the histological specimens showed the presence of a gap between the newly formed cementum and the underlying dentin. Control sites did not exhibit any cementum formation. The present study concluded that newly formed cementum is of cellular type and exhibits multiple characteristics.

One-year rotational relapse frequency following conventional circumferential supracrestal fiberotomy

BACKGROUND Relapse following orthodontic treatment has been a common problem that can occur due to several factors. It was suggested that surgical circumferential supracrestal fiberotomy(CSF) is an effective measure to reduce this relapse.However, very few studies have reported the amount of relapse that occurs afterward.AIM To assess the frequency of rotational relapse on anterior teeth 1 year following CSF.METHODS Eleven adults(six male and five female) with a mean age of 23 years(standard deviation = 5.2), who had a total of 90 rotated anterior teeth, were included in this study. CSF was performed after comprehensive orthodontic treatment involving the use of full-fixed preadjusted edgewise appliances(Victory Series APC, 3 M,United States) with a 0.022-inch slot and Roth prescription brackets(Ovation;DENTSPLY GAC, Bohemia, New York, United States) and placement of a fixed lingual retainer from canine to canine in both arches using a 0.016 Australian wire(AJ Wilcock, Australia). Degrees of rotational correction and relapse were measured on three sets of casts [pretreatment, post-treatment(at the debond visit), and 1-year post-treatment]. Rotational relapse was categorized as follows:Unnoticeable relapse(0°), barely noticeable relapse(1°-3°), noticeable relapse(4°-9°), and clearly noticeable relapse(≥ 10°). The percent relapse that had occurred 1 year after teeth were aligned to their ideal position was calculated. Data were analyzed by dental arch type and tooth types.RESULTS Mean rotational correction was 14.05° during posttreatment. Mean relapse at 1-year follow-up was 1.1°(10.8%). More than half(n = 52, 57.8%) of teeth were categorized as having unnoticeable relapse(0°). Of the remaining teeth, 31(34.5%) had barely noticeable relapse(1°-3°), 6(6.6%) had noticeable relapse(4°-9°), and only one(1.1%) had clearly noticeable relapse(> 10°). When analyzed by arch, 54.5%(n = 6) of the relapsed maxillary teeth had barely noticeable relapse(1°-3°). While most of the mandibular teeth(3, 37.5%) fell into noticeable relapse category(4°-9°), only 1(12.5%) tooth had clearly noticeable relapse(≥ 10°).CONCLUSION When relapse was measured following CSF, it was found to be more pronounced in maxillary than in mandibular arch. Most frequent relapse was found in maxillary lateral incisors and mandibular canines.