Assessment modalities of non-ionizing three-dimensional images for the quantification of facial morphology, symmetry, and appearance in cleft lip and palate: a systematic review.

The use non-ionizing three-dimensional (3D) imaging in cleft lip and palate is an emerging field, but properly designed methods for the assessment of these images are not well established. Therefore, the aim of this study was to review the current literature on the modalities of assessment of non-ionizing 3D images for the quantification of facial morphology, symmetry, and appearance in cleft lip and palate, and to assess the method error of these modalities. A systematic literature search was conducted using MEDLINE (PubMed), Cochrane Central Register of Controlled Trials, Web of Science, and Embase. Cross-sectional studies with prospective or retrospective data collection, using non-ionizing 3D imaging, with a subjective or objective outcome assessment and including at least 10 cleft lip and/or palate patients were considered eligible. Overall, 1767 unique studies were identified and 33 met the inclusion criteria. The images were objectively assessed using elementary measurements and comprehensive statistical methods for superimposition, shape description, and structuring. Subjective assessment was performed using a Likert-type scale or visual analogue scale. It can be concluded that non-ionizing 3D images are widely used in cleft research, but 3D analysis of the images is often methodologically suboptimal. Researchers must fully utilize the content of 3D images to quantify morphology, symmetry, and appearance.

Pulpal regeneration and root development after subcutaneous transplantation of cryopreserved immature teeth in rats.

The purpose of this in vivo study was to investigate revascularization and root growth after autotransplantation of cryopreserved immature teeth. Immature molar teeth were extracted in 4-week-old Wistar rats. In the test group, teeth were cryopreserved for 1 week and transplanted subcutaneously to the abdomen. In the control group, teeth were transplanted subcutaneously immediately after extraction. Material was collected in test and control animals at intervals of 1, 2, 4 and 10 weeks post-transplantation and histological and microradiographical examination was performed. Results showed that during the first weeks after transplantation, pulpal repair was similar in both groups although degenerated pulpal tissue was replaced slower in cryopreserved teeth and some differences in types of hard tissue formation were found between test and control teeth. After 10 weeks, the differences in the regenerated pulpal tissue between cryopreserved and control teeth observed during the first weeks were no longer detectable. No root growth was detected microradiographically 10 weeks after transplantation in any of the transplanted teeth. The presence of dentin-like tissue in the pulp cavity of some autotransplanted cryopreserved teeth, suggests survival of pulpal tissue after cryopreservation.

Apical root resorption of upper incisors during the torquing stage of the tip-edge technique.

The purpose of this study was to investigate whether treatment with the Tip-Edge appliance resulted in more apical root resorption (ARR) of the central and lateral incisors during the torquing (third stage) than the non-torquing phases (first two stages) of orthodontic treatment. The three stages of this orthodontic technique make it possible to examine the amount of root shortening during torque separately from other types of tooth movement. The ARR ratio was calculated in 31 Caucasian patients (20 females, 11 males), after the non-torquing stage of treatment and after the torquing phase, by analysing periapical radiographs taken at the beginning of treatment (T1), before the start of the torquing stage (T2), and at the end of treatment (T3). At T1, the mean age was 13 years 6 months (+/- 3 years 3 months). The mean, standard deviation and range of the ARR ratios were calculated and compared (P < 0.001). T-tests were performed to determine levels of significance, at different stages of treatment, between teeth with and without ARR (ARR ratio = 1). Root shortening at T3 was observed for 70 per cent of the central and 76 per cent of the lateral incisors. At T2, ARR was 48 and 53 per cent, respectively. Compared with T2, 38 per cent of the central incisors and 55 per cent of the lateral incisors showed ARR during the application of torque. At T3, the finding for both was 22 per cent. The mean ARR ratio for the central and lateral incisors was the same after the non-torquing stage of treatment but was significantly different from a tooth with no root resorption. After the torquing stage, the ARR ratio for the central incisors was 0.96 and for lateral incisors 0.92. At the end of treatment, the ratio was 0.89 and 0.85, respectively. This study revealed that both the central and the lateral incisors showed comparable amounts of ARR during the torquing and non-torquing stage of Tip-Edge treatment.

[Orthodontics based on a new scientific method of evaluating results: "evidence-based"]. / L'orthodontie basé sur une nouvelle méthode scientifique d'evaluation des résultats: l'"evidence-based".

In the orthodontic literature, randomized clinical trials are used to establish standards for the comparison of different clinical approaches. The balancing effect produced in a randomized study makes it possible to attribute the differences in results achieved clearly to treatment and not to variations in the biological characteristics of the patients involved. Recently, most randomized studies in orthodontics have been devoted to testing the hypothesis that some orthodontic appliances exert orthopedic effects that modify dento-facial growth. The authors propose definitions of "orthopedic effects" and of "dento-alveolar changes" and discuss the difficulties encountered in measuring them. They also review clinical studies published over the past 10 years on the correction of Class II malocclusions, on the problems of expansion and also report on Class IIl disorders. In addition they assess the problems associated with these clinical studies such as the ethical requirement of assuring that control groups receive treatment as appropriate for their maladies as that delivered to patients under study, the high cost of carrying them out, the relatively long delay before results can be evaluated, the difficulties of measuring all the different parameters involved, and the need to assemble large enough samples. To sum up, one can conclude that, because of all these impediments, randomized clinical studies have not as yet delivered the hope for benefit of collecting enough "evidence based" information for the orthodontic profession to deliver better treatment to its patients.

A 2-year outcome audit of a versatile orthodontic bone anchor.

This study examined complications leading to, or possibly leading to, treatment failure, related to the use of the orthodontic bone anchor (OBA). The OBA is a potential means of providing absolute anchorage and consists of a base-plate fixed with mono-cortical screws, a neck piercing the soft tissues, and a coronal part with conventional orthodontic hooks, tubes or slots. The investigation took the form of a single centre prospective registry at a supra-regional teaching hospital. Eighteen patients (average age 21 years) had one to four OBAs placed between January 2000 and February 2002. Altogether 35 OBAs were placed. Follow-up took place until April 2004. Reasons for placing the OBAs were noted together with any associated complications during the follow-up period. Twenty-three OBAs have been removed so far, four prematurely (one of them before it was taken into use, due to a change of treatment plan enforced by loss of the contralateral OBA). Nineteen were removed as planned after completion of the intended tooth movements. Common (but minor) complications included granulations, acute gingivitis and gingival recession. Light mobility of the OBA was also noted in some cases, but without clinical repercussions. The OBA can be loaded directly, at the level of the orthodontic archwire or more occlusally. It can be placed at any site at the circumference of the jaws, given good quality and thickness of the bony wall. Conventional biomechanical techniques can be applied. However, the failure rate (premature loss of OBA) of 8.6% is considered high, and has necessitated changes in the hardware and protocol.

[Tooth transplantation: an extra dimension in orthodontics]. / Tandtransplantaties: een extra-dimensie in de orthodontie.

In the first part of the presentation, the content of orthodontics has been briefly explained by means of some clinical cases. The main part of the presentation consisted of discussing patient treatment by means of autogenous tooth transplantation with special emphasis on its indications and contra-indications. When a tooth transplantation is carried out properly, a success percentage of 90%, even forty years after treatment, can be expected. This high percentage has been reported in a recent study. The success of tooth transplantation is mainly due to the timing of the transplantation and the non-traumatic handling during surgery. According to the literature, the ideal moment for tooth transplantation is when half to three quarters of the root has been formed. One of the indications for tooth transplantation is the transplantation of a tooth in the cleft of a cleft palate patient. Two cleft palate patients have been presented in which tooth transplantation was carried out after bone grafting in the alveolar cleft. Finally some findings of a recent study, carried out at our department, dealing with cryopreservation of teeth before transplantation, has been presented. According to the findings of this study, cryopreservation, after removal of the pulp tissue does not inhibit the normal ingrowth of new pulp tissue after transplantation.

Stability of implants as anchorage for orthopedic traction.

The aim of this animal study was to investigate the stability of osseointegrated fixtures when used as anchorage for orthopedic traction with extreme force magnitude. Three Brånemark fixtures were placed in the left zygomatic arch and three in the right of five adult dogs. An orthopedic nonaxial force of 5 N was applied using an intraoral coil system. The initial displacement immediately after force application was measured by means of speckle interferometry. After 2 months of continuous loading, bone adaptation and mineralization around all implants were analyzed. All the loaded implants were immobile. Significant marginal bone loss at the abutment-fixture interface (<1 mm) was observed around each loaded fixture implant. Bone remodeling was significantly more pronounced at the tension side of the implants, irrespective of fixture length. Radiographical and histological analyses showed bone with normal trabecular pattern around the implants.

Initial orthopaedic displacement compared with longitudinal displacement of the maxilla after a forward force application. An experimental study in dogs.

The aim of this study was to compare the initial orthopaedic displacement of the maxilla in vivo and the longitudinal changes after a forward force application. The sample consisted of five 1-year-old dogs. An anterior force of 5 N on the maxilla was applied by a coil spring system pushing between Brånemark implants and a maxillary splint. The initial displacement of the maxilla after force application was measured by means of speckle interferometry. The longitudinal displacement of the maxilla after a force application during 8 weeks was measured by superimposing standardized lateral cephalograms. The initial, as well as the longitudinal, displacement of the maxilla of the dogs was in a forward direction with some counterclockwise rotation. There was no statistical difference between the initial and longitudinal displacement. The biological response after force application during 8 weeks can be predicted by the initial orthopaedic displacement.