Evidence-based orthodontics, still a long way to go

Clinical performance can be kept up to date by learning how to practice evidence-based orthodontics, by seeking and appraising evidence-based summaries from the literature and by applying evidence-based strategies to change clinical behaviour. A MEDLINE search over the period 1990-2000 identified 8345 publications on clinical orthodontic subjects. Of these articles 49.5% was published in five specific orthodontic journals, while the others were published in about seventy other journals making it difficult for the clinician to stay current easily. Systematic reviews are an efficient and reliable source of information, but due to a lack of well-designed randomised clinical trials systematic reviews in orthodontics are still rare.     

Primary and secondary cartilages of the neonatal rat: the femoral head and the mandibular condyle

Primary and secondary cartilages differ in embryonic origin and in histological organization, and are generally considered to have a different mode of growth. However, few studies have directly compared the two types of cartilage of the same animal at the same age. Therefore, we analysed several histological and biochemical differences between secondary cartilage of the mandibular condyle and primary cartilage of the femoral head of 4-d-old rats. We evaluated the tissue organization, the level of DNA and glycosaminoglycan (GAG) synthesis, and the GAG and collagen content. The expression of collagen types I, II and III and of receptors for insulin-like growth factor (IGF)-I, fibroblast growth factor (FGF), and transforming growth factor (TGF)-beta were investigated by immunohistochemistry. The ex vivo DNA and GAG synthesis as well as the GAG content of femoral heads were much higher than that of mandibular condyles. Mandibular condyles expressed both collagen types I and II, while femoral heads expressed only type II collagen. In the mandibular condyles, receptors for IGF-I, FGF, and TGF-beta were observed mainly in the superficial layers, whereas they were found throughout the entire femoral head. In conclusion, major differences were found between both types of cartilage, which might be related to their specific functional demands.     

Infant orthopedics in UCLP: effect on feeding, weight, and length: a randomized clinical trial (Dutchcleft).

OBJECTIVE: To study the effects of infant orthopedics (IO) on feeding, weight, and length. DESIGN: Prospective two-arm randomized controlled trial in three academic Cleft Palate Centers. Treatment allocation was concealed and performed by means of a computerized balanced allocation method. SETTING: Cleft Palate Centers of Amsterdam, Nijmegen, and Rotterdam, the Netherlands. PATIENTS: Infants with complete unilateral cleft lip and palate (UCLP), no other malformations. INTERVENTIONS: One group (IO+) wore passive maxillary plates during the first year of life, but the other group (IO-) did not. All other interventions were the same for both groups. MAIN OUTCOME MEASURES: Bottle feeding velocity (mL/min) at intake, 3, 6, 15, and 24 weeks (T0 to T24); weight-for-age, length-for-age, and weight-for-length using z scores; reference values from the Netherlands' third nationwide survey on growth. RESULTS: Feeding velocity increased with time from 2.9 to 13.2 mL/min in the IO- group and from 2.6 to 13.8 mL/min in the IO+ group; no significant differences were found between groups. Weight-for-age, length-for-age, and weight-for-length (z scores) did not differ significantly between groups, but overall the infants with unilateral cleft lip and palate in both groups had significantly lower mean z scores for weight-for-age and height-for-age than the reference during the first 14 months, and had lower mean values for weight-for-length after soft palate closure. CONCLUSION: Infant orthopedics with the aim of improving feeding and consequent nutritional status in infants with unilateral cleft lip and palate can be abandoned.     

Optimum force magnitude for orthodontic tooth movement: a mathematic model.

The aim of this study was to develop a mathematic model to describe the relationship between magnitude of applied force and rate of orthodontic tooth movement. Initially, data were extracted from experimental studies in dogs (beagles), in which controlled, standardized forces were used to move mandibular second premolars distally. Curve-fitting by nonlinear regression analysis provided an equation describing the relationship between force magnitude and rate of tooth movement in beagles. A similar equation was subsequently used to analyze the limited available data from the literature on human canine retraction. The maximum rates of tooth movement in humans and dogs are very similar. A threshold for force magnitude that would switch on tooth movement could not be defined. The model showed that a wide range of forces can be identified, all of which lead to a maximum rate of tooth movement.     

A two-centre study on facial morphology in patients with complete bilateral cleft lip and palate at nine years of age

The aim of this study was to compare craniofacial morphology and soft tissue profiles in patients with complete bilateral cleft lip and palate at 9 years of age, treated in two European cleft centres with delayed hard palate closure but different treatment protocols. The cephalometric data of 83 consecutively treated patients were compared (Gothenburg, N = 44; Nijmegen, N = 39). In total, 18 hard tissue and 10 soft tissue landmarks were digitized by one operator. To determine the intra-observer reliability 20 cephalograms were digitized twice with a monthly interval. Paired t-test, Pearson correlation coefficients and multiple regression models were applied for statistical analysis. Hard and soft tissue data were superimposed using the Generalized Procrustes Analysis. In Nijmegen, the maxilla was protrusive for hard and soft tissue values (P = 0.001, P = 0.030, respectively) and the maxillary incisors were retroclined (P < 0.001), influencing the nasolabial angle, which was increased in comparison with Gothenburg (P = 0.004). In conclusion, both centres showed a favourable craniofacial form at 9-10 years of age, although there were significant differences in the maxillary prominence, the incisor inclination and soft tissue cephalometric values. Follow-up of these patients until facial growth has ceased, may elucidate components for outcome improvement.     

Oral health-related quality of life before,during, and after orthodontic-orthognathic treatment: a systematic review and meta-analysis

Clinical Oral Investigations - The effect of combined orthodontic-orthognathic treatment was estimated, specifically the impact of pre-surgical orthodontic treatment, on oral health-related quality...     

Three-dimensional evaluation of soft tissue changes in the orofacial region after tooth-borne and bone-borne surgically assisted rapid maxillary expansion

Objectives

This study seeks to three-dimensionally assess soft tissue changes in the orofacial region following tooth-borne and bone-borne surgically assisted rapid maxillary expansion (SARME).

Materials and methods

This prospective cohort study included 40 skeletally mature patients with transverse maxillary hypoplasia. A tooth-borne distractor (Hyrax) was used for expansion in 25 patients. In the remaining 15, a bone-borne distractor (transpalatal distractor, TPD) was used. Cone beam computed tomography (CBCT) scans were acquired before treatment (T0) and 22 months later (T1). 3D models were constructed from CBCT data and superimposed using voxel-based matching. Distance maps between the superimposed 3D models were computed to evaluate the degree of skeletal and soft tissue changes in the maxillary region.

Results

Distance maps showed negative distances (mean ?1.25 (±1.5) mm) in the middle of the upper lip, indicating posterior repositioning of this area. The cheek region showed positive changes (mean 1.66 (±1.1) mm), reflecting the underlying increase in maxillary width. There was no significant difference between the two groups in all measured distances (p?>?0.05). Retro-positioning of the upper lip accompanied skeletal remodeling in the anterior alveolar region at a mean ratio of 88 %, while the cheek region followed 32 % of the alveolar expansion.

Conclusion

Soft tissue changes following SARME include posterior repositioning of the upper lip and increased projection of the cheek area. These changes were comparable between bone-borne and tooth-borne appliances.

Clinical relevance

This study provides clinicians with more information over the expected orofacial soft tissue changes following SARME     

4种支架构建复合式口腔黏膜的组织学特点

目的利用4种不同支架材料构建复合式口腔黏膜,并比较其组织结构特点。方法体外培养人口腔黏膜的成纤维细胞和角质形成细胞,在4种支架材料中加入成纤维细胞,培养7d后,在支架表面加入角质形成细胞,培养4d后,移至气-液界面继续培养7d。苏木精-伊红染色镜下观察构建的复合式口腔黏膜的组织形态学特点。结果 4种支架均可构建形成复层上皮。其中,上皮层与脱细胞真皮基质材料(de-epidermised dermis,DED)结合紧密,形成的人工黏膜有明显的上皮钉突。不同于以往报道,上皮层与Alloderm结合并不十分紧密。以胶原凝胶为基质形成的人工口腔黏膜最厚,有明显分层。以胶原海绵-胶原凝胶为基质形成的复层上皮在部分区域长入至胶原海绵的空隙中。结论以DED和胶原凝胶为支架构建的口腔黏膜更接近于天然结构,而后者脆性较大,限制了其临床应用的可能。     

Variability in dentofacial phenotypes in four families with WNT10A mutations

This article describes the inter- and intra-familial phenotypic variability in four families with WNT10A mutations. Clinical characteristics of the patients range from mild to severe isolated tooth agenesis, over mild symptoms of ectodermal dysplasia, to more severe syndromic forms like odonto-onycho-dermal dysplasia (OODD) and Schöpf–Schulz–Passarge syndrome (SSPS). Recurrent WNT10A mutations were identified in all affected family members and the associated symptoms are presented with emphasis on the dentofacial phenotypes obtained with inter alia three-dimensional facial stereophotogrammetry. A comprehensive overview of the literature regarding WNT10A mutations, associated conditions and developmental defects is presented. We conclude that OODD and SSPS should be considered as variable expressions of the same WNT10A genotype. In all affected individuals, a dished-in facial appearance was observed which might be helpful in the clinical setting as a clue to the underlying genetic etiology.