Clinical crown length of the maxillary anterior teeth preorthodontics and postorthodontics

BACKGROUND: Prevalence information on excessive gingival display in postorthodontic patients is limited. By studying the size relationship of the clinical crowns of teeth, in an orthodontic population, we can begin to quantify their need for periodontal plastic surgery. METHODS: Preorthodontic and postorthodontic crown dimensions were measured on 200 plaster models, and after 5 years, 31 of the subjects were recalled to repeat the measurements in a clinical examination. The measurements included clinical crown lengths and widths of the six anterior teeth, and these values were compared to known ideals. RESULTS: This study revealed a significant increase in the length of the maxillary anterior crowns over the three examinations, yet these values were still approximately 1.5 mm shorter than ideal. The mean crown width-to-length ratio was 87% to 88% for maxillary central incisors, clearly above the accepted "ideal." In addition, 61% to 71% of maxillary central incisors exceeded allowable crown width-to-length ratios, and 61% of subjects displayed asymmetry in gingival architecture. CONCLUSIONS: Although this study only examined one aspect of excessive gingival display, to our knowledge it is the first study to show that in a predominantly young, postorthodontic population, the prevalence of non-ideal width-to-length ratios is >65% and the presence of asymmetry is >60%. Therefore, close interaction between the periodontist and the orthodontist is necessary to diagnose these conditions to provide patients with all options for improving their smile.     

Long-term evaluation of bilateral cleft lip and palate patients after early secondary closure and premaxilla repositioning

The aim of this retrospective, mixed longitudinal study was to assess the long-term outcome of early secondary closure and premaxilla osteotomy in 40 bilateral cleft lip and palate patients who underwent early secondary osteotomy of the premaxilla and bone grafting at the age of 8-12 years. Clinical and cephalometric evaluations of profile, lip relation, nasolabial angle and position of the maxilla preoperatively, postoperatively and at adolescence were compared to normal values of non-cleft individuals and the reported data of 90 bilateral cleft lip and palate patients treated in Oslo. In 68% of patients the profile was considered acceptable, but in 26 maxillary growth appeared to be impaired by cephalometric standards. In four patients a Le Fort I osteotomy was carried out and nine patients would have benefited from such a procedure. This study reveals a trend towards maxillary growth retardation partially compensated by orthodontic and dental treatment. Since the results are comparable to those reported for the Oslo group with regard to maxillary growth, the surgical protocol followed does not require revision. Considering the benefits, i.e. closure of alveolo-palatal cleft, continuity of dental arch, eruption of canine in the graft and closure of oro-nasal communications, this mode of treatment should be continued.     

Lateral alveolar ridge augmentation using a synthetic nano-crystalline hydroxyapatite bone substitution material (Ostim): preliminary clinical and histological results

OBJECTIVES: The purpose of this preliminary two-center clinical prospective study was to evaluate the tissue composition of augmented sites after the use of a nano-crystalline hydroxyapatite (ncHA) bone substitution material by clinical and histological examinations. MATERIAL AND METHODS: A synthetic ncHA augmentation material was used without any additives in 14 patients requiring lateral ridge augmentation 6-7 months before (10 patients) or at implant placement (four patients). The ncHA material was covered by a titanium mesh for space maintenance. Clinical and radiographic parameters were evaluated and bone biopsy cores, obtained 6-7 months following augmentation, were assessed histologically and histomorphometrically. RESULTS: One patient showed gingival swelling, redness and pain at the augmentation site requiring removal of the titanium mesh 6 weeks postoperatively. In seven patients, a premature exposure of the titanium mesh without any inflammatory symptoms was noted. The width of the fixed gingival and the alveolar ridge height did not change significantly at least 6 months following augmentation (P>0.5), whereas a significant gain in alveolar ridge width (P=0.01) was noted. After a median period of prosthetic loading of 24 months, no implant was considered to be a failure. Histology revealed ncHA remnants in peripheral and central parts of biopsy cores obtained from seven patients after at least 6 months without histological symptoms of inflammation, whereas histomorphometry of bone cores revealed no significant differences of the mean percentage area of ncHA in peripheral (23.4%) and central (15.1%) parts of biopsy cores (P=0.262). The mean percentage area of bone colonizing the defect was 52.3%. CONCLUSIONS: Small amounts of ncHA were found after at least 6 months in bone biopsies. The former defect space was filled with bone. The alveolar ridge width gain was found to be significant after lateral augmentation utilizing ncHA, providing a quantitatively and qualitatively sufficient site for primary stable implant placement.     

Outcome of secondary alveolar bone grafting before and after eruption of the canine in Jordanian patients with cleft lip and palate

This prospective study was carried out at the Cleft Lip and Palate Centre at King Abdullah University Hospital and Maxillofacial Unit at Jordan University of Science and Technology during the period of 2000 to 2006. The sample consisted of 77 secondary alveolar bone grafts (62 patients), which were performed according to the same standardized surgical technique by a single maxillofacial surgeon.The objective was to assess the outcome of secondary alveolar bone grafting (SABG) before (early SABG) and after (late SABG) the eruption of the permanent maxillary canine in unilateral and bilateral Jordanian cleft subjects. Patients were divided into four groups: early unilateral SABG (22), late unilateral SABG (25), early bilateral SABG (8), and late bilateral SABG (7). Follow-up period ranged from 6 months to 5 years. Periapical or occlusal radiographs were used to assess the outcome of SABG. The degree of bony fill in the cleft area was assessed using the 4-point Kindelan scale. Only Grade 1 (more than 75% bony fill) cases were considered successful. Early unilateral SABG had a success rate of 90% while late unilateral SABG rate was 80%. The overall success rate of the unilateral SABG (85%) was higher than the rate for the bilateral cases (56%). Our findings support the conclusion that the outcome of early SABG is superior to late SABG. The overall success rate of SABG sample (74%) compared relatively well with other published results.     

口腔鳞状细胞癌新辅助治疗和辅助治疗的长期生存率：前瞻性、非随机性研究

最近对口腔鳞癌的治疗观念发生了变化，其中包括新辅助治疗（术前化疗、手术、术后放疗）及辅助治疗（手术、术后放疗）。该文旨在对2种治疗方法对患者长期生存率的影响进行了比较。方法：将患者分为2组，一组74例，行新辅助治疗，另一组54例行辅助治疗。99例为Ⅲ-Ⅳ期的患者，     

Frontal cephalometric study of dentofacial morphology in children with bilateral clefts of lip, alveolus and palate

The transverse dentofacial morphology of 36 children with bilateral cleft lip, alveolus and palate was studied by means of a frontal proportional cephalometric analysis at the ages of three, eight and twelve years. Comparison of the variables of the cleft group was made with the normal dimensions as obtained from the Bolton cephalometric templates. The results indicated that the BCLP group presented characteristics and significant differences from the normal in the dimensions of the nasal septum width and the mandibular intergonial width as they are both related to the interorbital width, the maxillary intermolar width as it is related to the mandibular intermolar width and the maxillary width as it is related to the mandibular intergonial width at all three ages. The maxillary base and intermolar widths, although significantly different at the ages of three and eight years, showed no significant deviation from normality at the age of twelve years. Following orthodontic treatment between the ages of seven to twelve years, the maxillary intermolar width of the treated subgroup was significantly larger than in the untreated subjects.     

Okklusion,Kiefergelenke und kieferorthopädische Behandlung

Zusammenfassung Für die Okklusion und den Gelenkbereich sind Zuordnungsnormen existent. Dies ist im Seitenzahnbereich die Höcker-Fossa-Relation, im Frontzahnbereich die Zuordnung der Unterkiefer-Inzisalkanten zu der Nullpunktlinie der palatinalen Konkavitäten im Oberkiefer und im Gelenkbereich die physiologische Kondylenposition. Letztere läßt sich im Pantogramm durch den Wendepunkt der von der Achse bei sagittaler Grenzführung gezeichneten Kurve präzisieren, in Übertragung aber auch im Röntgenbild ermitteln.Ziel der kieferorthopädischen Behandlung sollte die physiologische Zuordnung von Seitenzähnen, Frontzähnen und Gelenken sein. Das vorgestellte Funktionsmodell gibt Hilfestellungen bei der Behandlung auf ein funktionelles Optimum hin.Die Gelenke sind bei der Behandlung wie ein eigenes terminales Okklusionspaar zu betrachten. Ihre korrekte Einstellung läßt sich bisher nur durch Röntgenbilder und durch die pantographische Aufzeichnung darstellen.

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Summary We are convinced that there is a relation between the occlusion and the temporomandibular joint. In the molar region the correlation is known as the cusp-fossa relationship. In the incisor region the corresponding structures are the mandibular incisor tips and the palatal concavities of the upper incisors. We have designated the correlation in the TMJ-region as the physiological condyle position, which can be identified in the sagittal pantogram by the turning point of the traced sigmoid curve. Similarly this position can be shown by our method on the TMJ-radiograph.The aim of orthodontic treatment should be a physiological positioning of molars, incisors and joints. The functional model presented above can render assistance in achieving a functional optimum in treatment.The temporomandibular joints must be regarded in treatment as additional occluding points. Up to now their correct positioning has been visible only through the use of TMJ-radiographs and pantographic tracings.

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Résumé Il existe des normes structurelles correspondantes entre l'occlusion et l'articulation temporomandibulaire; à savoir dans les zones latérales d'arcades la relation cuspide-sillon, dans le segment antérieur l'arête des incisives inférieures glissant le long des faces palatines des incisives supérieures jusqu'à la ligne d'arrêt et au niveau de l'articulation la position physiologique du condyle. Cette corrélation s'établit dans le plan sagittal du pantogramme par l'existence d'un point tournant du tracé sigmoïde; on peut transposer cette position dans l'image radiographique.Le but d'un traitement orthodontique est de coordonner physiologiquement les segments latéraux et antérieur d'arcades et l'articulation temporo-mandibulaire. Des moulages fonctionnels préétablis nous aident à obtenir la meilleure fonction au cours du traitement.On doit considérer la double articulation temporo-mandibulaire comme une occlusion finale. Seuls la radiologie et les tracés pantographiques permettent de juger de la position correcte des condyles dans leurs fosses glénoïdes.

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In memoriam Herrn Prof. Dr.G. Müller von seinen ehemaligen Schülern und Mitarbeitern.