Impact of piezocision on orthodontic tooth movement.

OBJECTIVE: This study investigated the impact of a single piezocision in the maxillary alveolar process on the speed of tooth movement. The null hypothesis was that the speed of tooth movement will be equal with and without piezocision. METHODS: All maxillary molars on one side were moved against the combined incisors in 10 ten-week-old male Wistar rats. Under general anesthesia, a force of 25 cN was applied on either side using a Sentalloy closed coil spring. After placing the orthodontic appliance, vertical corticision was performed using a piezotome under local anesthesia, 2 mm mesial from the mesial root of the first molar on a randomly selected side; the other side served as the control. At the beginning of the treatment, and 2 and 4 weeks later, skull micro-computed tomography was performed. After image reconstruction, the distance between the mesial root of the first molar and the incisive canal, and the length of the mesial root of the first maxillary molar were measured. Moreover, the root resorption score was determined as described by Lu et al. RESULTS: Significantly higher speed of tooth movement was observed on the corticision side; thus, the null hypothesis was rejected. The loss of root length and root resorption score were significantly more pronounced after piezocision than before. A strong correlation was observed between the speed of tooth movement and root resorption on the surgical side, but the control side only showed a weak correlation. CONCLUSIONS: Piezocision accelerates orthodontic tooth movement and causes increased root resorption.

A comparison of different sealants preventing demineralization around brackets.

AIM: Aim of the study was to compare how six different sealants resisted thermal, mechanical, and chemical loading in vitro. MATERIALS AND METHODS: In all, 120 extracted human, nondecayed molars were divided into six groups (20 samples each) and embedded in resin blocks. The buccal surfaces of the tooth samples were polished and divided into three areas. Area A contained the product to be analyzed, area B was covered with colorless nail varnish (negative control), and area C remained untreated (positive control). The samples were stored in 0.1% thymol solution. To simulate a 3-month thermomechanical load, the samples were subjected to thermal cycling and a cleaning device. After 7 days incubation in a ten Cate demineralization solution (pH value: 4.6), the samples were dissected using a band saw and the lesion depths and demineralization areas were evaluated and compared microscopically. RESULTS: The tooth surfaces treated with PRO SEAL® showed no demineralization. Mean lesion depths of 108.1, 119.9, 154.9, 149.2, and 184.5 µm were found with Alpha-Glaze®, Seal&Protect®, Tiefenfluorid®, Protecto®, and Fluor Protector, respectively. There was a significant difference between PRO SEAL® and the other products (p > 0.0001). There was no significant difference between the other products. CONCLUSION: PRO SEAL® resisted thermal, mechanical, and chemical loading in vitro, providing protection against white spot lesions.

Influence of piezotomy and osteoperforation of the alveolar process on the rate of orthodontic tooth movement: a systematic review.

OBJECTIVE: The minimally invasive procedures piezosurgical corticocision and osteoperforation have been advocated as methods to accelerate orthodontic tooth movement and to shorten treatment time, but without large-scale trauma of the periosteum and the bone. The aim of this study was to evaluate if there is evidence supporting these claims based on a systematic review of the literature. MATERIALS AND METHODS: A search of PubMed and Google Scholar with the combined search terms "piezo*" and "tooth movement" was performed until May 2016. In addition, the keywords "osteoperforation" and "piezopuncture" were searched in both databases. All scientific articles were considered and examined for suitability by two scientists. Disagreements resolved by consensus. The first inclusion criterion was studies with human species. Second inclusion criterion the surgical procedure had to be performed transmucosally and without the elevation of a mucoperiosteal flap. Case series were also considered. RESULTS: The Google Scholar search delivered 516, the PubMed search 60 references. A total of 36 human trials fulfilling the first inclusion criterion were identified. Among those, in only 13 publications was a transmucosal technique used (12 on piezosurgical corticocision and 1 on osteoperforation). Of the 13 articles, 9 represented case series and only 4 were clinical trials. In all four trials, an acceleration of the orthodontic treatment was reported. However, the extent of the acceleration was inconsistent and in one article it disappeared when assessing the overall orthodontic treatment. CONCLUSION: Evidence for an acceleration of tooth movement in conjunction with the minimally invasive methods piezosurgical corticocision and osteoperforation of the alveolar process in humans is low.

Effect of untreated and treated temporomandibular joint arthritis on mandibular volume development in growing rabbits.

OBJECTIVES: The goal of this work was to investigate the volume development of the mandible in growing rabbits with bilaterally induced temporomandibular joint (TMJ) arthritis that was either left untreated or treated with the tumor necrosis factor-alpha (TNF-α) antagonist etanercept. METHODS: A total of 18 New Zealand White rabbits aged 8 weeks were randomized to three groups of 6 animals each. Two of these groups were used as arthritis groups by sensitizing the 12 animals to ovalbumin (OA) at 10 weeks, followed by intraarticular OA injections to induce bilateral TMJ arthritis and repeating these injections every 3 weeks to maintain the inflammation. One of the two arthritis groups was treated by weekly subcutaneous etanercept injections, whereas the other group was left untreated. The remaining 6 animals served as controls. Maxillofacial CT scans were obtained at 3-week intervals (from week 10 of the rabbits' lives to the end of the experiment at 22 weeks) to volumetrically track the development of the mandibles after segmentation. RESULTS: The mandibles did not grow at a continuous rate, but the rate of development was found to decrease in all groups over the course of the study (weeks 10-22). The most extensive volume increases were noted during weeks 10-13. Severe growth deficiencies, especially of the condylar processes, were observed in the arthritis group not receiving treatment. The arthritis group treated with etanercept showed better rates of growth without, however, reaching the normal range of the control group. CONCLUSION: Antigen-induced TMJ arthritis was found to involve severe problems of growth similar to those in juvenile idiopathic arthritis. Etanercept can improve the volume development but does not reestablish an entirely normal rate of growth.

Effect of methotrexate on the mandibular development of arthritic rabbits.

INTRODUCTION: Juvenile idiopathic arthritis affecting the temporomandibular joint (TMJ) can cause severe disturbances of the mandibular development. Methotrexate (MTX) is often administered as a common used remission-inducing agent to treat this disease. The aim of this study was to investigate the effect of low dose MTX on the mandibular growth in arthritic rabbits. SUBJECTS AND METHODS: Eighteen 10-week-old female New Zealand white rabbits were randomly assigned to three groups with six animals in each group. After being sensitized to ovalbumin (OA), the first and the second group received intra-articular injections with OA. The first group remained untreated, the second was treated by weekly injections of MTX. Cephalograms were taken from each animal at 10, 13, 16, 19, and 22 weeks of age and six mandibular distances measured. RESULTS: All distances showed an increase between 10 and 20 per cent, whereas growth was more accentuated in the sagittal dimension. Significant differences in the overall growth could be observed between the arthritic and the control animals and less accentuated between the arthritic and the MTX animals. In contrast, existing differences between the groups were not significant during the intervals, but time had the greatest influence on mandibular growth. CONCLUSIONS: MTX seems to have a positive impact on growth in rabbits suffering from experimental arthritis of the TMJ.

Investigation of bone conditions for orthodontic anchorage plates in the anterior mandible.

OBJECTIVES: The clinical success of orthodontic anchorage plates depends on the stability of the miniscrews used for fixation. For good stability, the application site must provide bone of good quantity and quality. This study was performed to analyze bone quantity for orthodontic anchorage plates in the anterior mandible. PATIENTS AND METHODS: A total of 51 computed tomography (CT) scans of fully dentate patients (mean age 24.0±8.1 years; 27 men and 24 women) were evaluated. Measurements were taken to analyze the total orovestibular and vestibular cortical thickness of the mandibular jawbone at different anterior locations and levels. RESULTS: Vestibular cortical thickness is generally thinnest within the incisor area on the apex level. Its thickness increases in basal and distal directions. The total orovestibular thickness is also the least on the level of the anterior mandibular apices, becoming thicker toward more basal levels and the posterior teeth. CONCLUSION: We can reasonably assume that the stability of anchorage plates can be optimized by selecting a position well basal to the apices of the lower incisors, as this area offers enhanced cortical and total jawbone thickness.

Remodeling along the bone-screw interface.

OBJECTIVE: The stability of cortical miniscrews depends on the contact between bone and implant. The aim of this study was to compare bone remodeling along the contact surface between the screw and bone with and without pre-drilling. MATERIALS AND METHODS: Twenty-four FAMI miniscrews (length 10 mm, diameter 2 mm) were inserted into the mandibular alveolar process apical to the premolars of four miniature pigs. Each pig received six screws, three on the one side with pre-drilling, three on the other side without pre-drilling. Polychrome fluorescent labels were used to assess the bone remodeling. After 12 weeks of osseointegration, all 24 screws and surrounding bone were removed. Microsections were prepared and analyzed histomorphometrically and under fluorescent microscopy. Differences between the groups were determined using the t test with a significance level of 5%. RESULTS: All the screws osseointegrated without any complications. Those without pre-drilling revealed a bone-screw contact of 64 +/- 11%, and those subjected to pre-drilling 63 +/- 12%. This difference was not significant. The mineral apposition rate, 1.6 +/- 0.4 microm/d and 1.7 +/- 0.4 microm/d, respectively, also failed to demonstrate any significant differences between the groups, while the portion of newly-formed bone in the pre-drilled group was significantly higher (59 +/- 9% vs. 27 +/- 6%). CONCLUSION: Significant differences in the bone-to-screw contact between the two groups are no longer in evidence after three months due to new bone formation. The minor extent of bone remodeling in the not pre-drilled group rules out substantial bone damage, which might have occurred during screw placement as a result of "cracks" or an excessive increase in pressure along the interface. The similar rate of new bone formation in both groups speaks against a stimulating effect of pre-drilling. Despite the absence of quantitative differences, it remains unclear whether the mechanical quality of the newly-formed bone resembles that of preexisting bone. Our findings seem to be applicable to the human mandible, however, its thinner cortical layer means less screw-to-bone contact is likely. We must reckon with less bone contact in the maxilla for the same reason.

Effect of intra-articular administration of buprenorphine after arthrocentesis of the temporomandibular joint: a pilot study.

OBJECTIVE: The purpose of this double-blind study was to evaluate the effect of intra-articular opioid injections on postoperative pain and joint mobility after arthrocentesis of the temporomandibular joint (TMJ). METHOD AND MATERIALS: Forty patients suffering from persistent pain in combination with anterior disc displacement (22 with reduction, 18 without reduction) and unresponsive to nonsurgical therapy underwent arthrocentesis of the affected TMJ under local anesthesia. All patients were randomly assigned to 2 groups. In group 1 (20 patients), 1 mL of buprenorphine solution was injected into the joint space at the end of the intervention; in group 2 (20 patients), 1 mL of saline was used. For postoperative pain management, all patients received Paracetamol ad libitum. Preoperatively and at postoperative days 2, 4, 7, and 14, individual pain levels were determined on a visual analogue scale together with maximum mouth opening. RESULTS: At days 2 and 4 after the intervention, remarkable differences were detectable between the 2 groups, showing a rapid normalization of joint mobility and pain scores in group 1; in contrast, improvement in group 2 was delayed. CONCLUSION: Intra-articular injections of long lasting opioids seem to influence joint mobility and pain positively within the first week after arthrocentesis.

Dental findings in patients with ectodermal dysplasia.

BACKGROUND: Ectodermal dysplasia is an inherited disease causing malformations of all tissues originating from the ectoderm. The significance of this disease lies in severe hypodontia, and an accompanying hypoplasia of the alveolar process. The clinical situation is aggravated by a significant xerostomia. It was the aim of this study to document the distribution of hypodontia and tooth malformation. Furthermore, we aimed to elucidate the clinical impact of these findings. PATIENTS AND METHODS: Records of 30 patients (19 males, 11 females) suffering from ectodermal dysplasia were included. Their age ranged between 7 and 23 years. All patients had been examined clinically and radiographically. In every patient, a record was made of which teeth were missing or malformed, and which deciduous teeth persisted. Additionally, the entire treatment procedure was assessed. RESULTS: The third molars were missing in all of the patients. The number of aplastic permanent teeth ranged from 2 to 26. The maxillary lateral incisors were most frequently absent, followed by the mandibular central incisors. The most stable teeth were the central incisors of the upper jaw, and the canines and first molars in both jaws. However, the maxillary central incisors and canines were the teeth most affected by malformation. Deciduous canines and second molars were the most often persisting teeth due to agenesis of the maxillary lateral permanent incisors and mandibular second premolars. In two-thirds of the patients, missing teeth were replaced by removable dentures. Half of the patients received orthodontic treatment. CONCLUSIONS: Hypodontia and malformation are almost regular dental characteristics in patients suffering from ectodermal dysplasia. The distribution of absent teeth deviates remarkably from the general population. Treatment requires an interdisciplinary approach including orthodontics, prosthodontics and oral surgery.