正畸病人后牙段腭弓形态的测量

目的:研究正畸病人后牙段腭弓形态的规律,为临床预成腭杠的制作提供理论基础.方法:选择60例正畸病人,按牙齿萌出情况(牙龄)分为3组,灌取上颌模型,测量第一磨牙区腭弓的高度、宽度和弧长,统计分析.结果:恒牙列组后牙段腭弓高度、宽度及弧长测量值最大,替牙组最小,有统计学意义.结论:牙列由替牙列向恒牙列的发育过程中,腭弓也在发育,其趋势是高度,宽度和弧长的不断增加,尤其以替牙列向恒牙期过度时,此变化最为明显(P＜0.01).临床使用腭杠时需注意腭部的这种特点.     

Malocclusion in the primary dentition

In this paper we analyze the type and frequency of malocclusions in a group of 100 health children with complete primary dentition. Bjork's method for epidemiological registration was taken as a basis. Of the examined children, 78% had some malocclusion type. The most frequent was the increased horizontal overbite. In vertical overbite relation we find anterior open bite, increased overbite, anterior open bite, increased overbite.     

Relationship of maxillary molar root angulation and palatal vault height

If the vertical angulation of maxillary molar roots could be reliably predicted, this might affect the choice of roots resection procedures. In an attempt to develop this prediction, angulation of palatal roots was compared to palatal vault height. Human cadaveric maxillae with molars were sectioned faciopalatally through each tooth root to the palatal midline and photographed. Root angles and palatal height were measured on the photographs in relation to a reference line connecting buccal and palatal cementoenamel junctions (CEJ). Palatal vault heights were classified as low, medium, or high according to the perpendicular distance from the midpalatal suture to the reference line. Root angles were subtended by a line following the length of pulp canals and perpendicular to the CEJ reference. Analysis by Spearman's Rank Correlation Coefficient demonstrated a weak nonsignificant relationship between palatal vault height and the angulation of the various maxillary molar roots. Thus, palatal vault height would not be a reliable predictor of root angulation if this were to be used as a basis for root retention.     

Functional contouring of the palatal vault for improving speech with complete dentures

A method for functionally modifying the contour of the palatal vault of maxillary complete dentures was described. This can be achieved at the trial stage of the denture construction and incorporated in the finished denture. Alternatively, the procedure can be accomplished at the time of insertion and the palatal vault modified with self-polymerizing acrylic resin. The immediate speech achieved by the modification is much more normal and eliminates the waiting and training period after denture insertion. Because the modification of the palatal vault is achieved by the functional contact of the tongue during articulation, the tongue does not have to adapt to the presence of the denture in order to achieve “normal speech.”One of the advantages of the method is the ease with which it can be performed in a clinical setting and the minimal requirement of any extra material or equipment. Moreover, no special skills are needed to achieve successful results, which can be exceptionally gratifying.     

Endodontic treatment in the primary dentition

A number of factors are involved in the development of pulp and periapical disease in primary and permanent teeth, with dental caries being the main factor. Although these factors are similar, the clinical management of a primary or permanent tooth with pulp or periapical disease may be quite different. This is based mainly on the differences between the two types of teeth, with primary tooth longevity, coronal structural integrity, root canal morphology, and root anatomy being important features to be taken into account when treatment planning. This paper reviews some aspects of primary teeth and the various treatment options for the management of pulp and periapical disease.     

Traumatic injuries in the primary dentition

Abstract  – As a support for the guidelines published in 2001, a review of the literature was carried out using the evidence-based approach in order to update the state of the art regarding epidemiology and treatment of traumatic dental injuries in the primary dentition. An online search in Medline, and a review of expert literature, lead to the conclusion that most luxation injuries heal spontaneously, and unless more conclusive evidence is available, conservative treatment of acute dental trauma for preschool children is suggested. Pain control, the dentist's ability to cope with the child's anxiety, and follow-up instructions in oral hygiene techniques will allow many primary teeth that are currently lost at the time of injury to be saved.     

Trauma to the primary dentition

The guiding principle in managing trauma to the primary dentition is potential sequelae to the permanent tooth. If the risk to the permanent tooth is great, the primary tooth should be removed. If esthetics are a concern to the parent, a number of appliances can be fabricated to temporarily manage this issue. It is important that parents realize that the desire to maintain optimum esthetics by maintaining a significantly injured primary tooth can, in many cases, cause more damage to the permanent tooth. Where avulsions have occurred, the old adage "when in doubt, leave it out" is still perhaps the most reliable advice.     

Orthodontic treatment of the primary dentition

Five patients were treated for corrections of problems in the primary dentition. Anterior and posterior crossbite, deep overbite malocclusion, and overbite malocclusion were treated with simple removable orthodontic appliances. Early orthodontic treatment for these patients helped resolve any functional problems that could interfere with later growth and development, such as health and function of the TMJ complex.     

Influence of width and depth of palatal vault on rigidity of palatal strap: A finite element study

PurposeThe purpose of this study was to develop design criteria for palatal straps according to palatal shape.MethodsThe palatal shapes of 60 dentate maxillary stone casts were measured using a contact-type three-dimensional measuring instrument. Based on the average of the 60 palatal shapes, 5 three-dimensional finite element models (FE models) were constructed: a basic FE model, a wide palatal FE model, a narrow palatal FE model, a deep palatal FE model and a shallow palatal FE model. The FE models were simulated unilateral free-end saddle dentures with the maxillary left second premolar and first and second molars missing. The FE models included a denture base, two rests and a palatal strap. The mechanical properties of Co–Cr alloy, Ti–6Al–7Nb alloy and type IV gold alloy were given to the FE models. A vertical load of 50 N was loaded onto the occlusal surface of the left first molar. Vertical displacement of the distal edge of the denture base was then compared between models.ResultsCompared to the basic FE model, displacement in the wide FE palatal model and shallow palatal FE model was larger, and displacement in the narrow palatal FE model was smaller. The difference in displacement between the deep palatal FE model and basic FE model was small.ConclusionsWith a wide and shallow palate, it is necessary to design a reinforced palatal strap. With a narrow palate, the anteroposterior width of the palatal strap can be narrower. With a deep palate, it is not necessary to change the palatal strap design according to the palatal shape.