Evaluation of the slope of the articular eminence and the transverse angle of the glenoid fossa in an Anatolian population.

The purpose of this study was to compare a computer-aided method specially programmed for the measurement of the posterior angle of the articular eminence with formerly used methods, to investigate the angulation differences at different depths of slices, and to evaluate correlation with the transverse angulation. Three slices (central, medial, and lateral) at various depths of the glenoid fossa belonging to 64 dry skulls and two measurement methods were used in this study. The angulation of the articular eminence were measured and the transverse angle of each fossa calculated. No statistical difference was found between the articular eminence results of the two methods. According to the results, the one factor ANOVA central slice was found to be statistically steeper than the other two slices (p < 0.05) (central = 60.33 +/- 10.19, medial = 58.26 +/- 8.6, lateral 58.28 +/- 10.1). No correlation was found between the transverse angle of the inclination of the posterior slope angulation. It was concluded that the computer-aided method is more reliable and accurate and is much easier to use when compared to the manual method. An additional important finding of this study is that the inclination of the articular eminence should be evaluated at various depths of the temporomandibular joint.

Update on oral lichen planus: etiopathogenesis and management.

Lichen planus (LP) is a relatively common disorder of the stratified squamous epithelia, which is, in many ways, an enigma. This paper is the consensus outcome of a workshop held in Switzerland in 1995, involving a selection of clinicians and scientists with an interest in the condition and its management. The oral (OLP) eruptions usually have a distinct clinical morphology and characteristic distribution, but OLP may also present a confusing array of patterns and forms, and other disorders may clinically simulate OLP. Lesions may affect other mucosae and/or skin. Lichen planus is probably of multifactorial origin, sometimes induced by drugs or dental materials, often idiopathic, and with an immunopathogenesis involving T-cells in particular. The etiopathogenesis appears to be complex, with interactions between and among genetic, environmental, and lifestyle factors, but much has now been clarified about the mechanisms involved, and interesting new associations, such as with liver disease, have emerged. The management of lichen planus is still not totally satisfactory, and there is as yet no definitive treatment, but there have been advances in the control of the condition. There is no curative treatment available; immunomodulation, however, can control the condition. Based on the observed increased risk of malignant development, OLP patients should be offered regular follow-up examination from two to four times annually and asked to report any changes in their lesions and/or symptoms. Follow-up may be particularly important in patients with atrophic/ulcerative/erosive affections of the tongue, the gingiva, or the buccal mucosa. Much more research is required into the genetic and environmental aspects of lichen planus, into the premalignant potential, and into the possible associations with chronic liver, and other disorders. More clinical studies are required into the possible efficacy of immunomodulatory drugs such as pentoxifylline and thalidomide.

Tensile bond strength of a soft lining with acrylic denture base resins.

Bonding of different soft lining materials has been widely investigated, but there is little work on the effect of using different denture base resins. This study investigates the bonding of Molloplast-B (a heat-cured, silicone soft lining material) and five commercial acrylic denture base materials of different types (Pacton, Lucitone, Meliodent, Ivocap and Compresin). The lining was processed against all the resins cured and Pacton, Lucitone and Meliodent uncured. In the cured specimens, Lucitone, Meliodent and Compresin demonstrated cohesive failure, whereas Pacton and Ivocap demonstrated part-adhesive and part-cohesive failure. All three sets of uncured specimens demonstrated adhesive failure. It was concluded that pre-curing, roughening and treating with Primo adhesive gives a better bond.

An analysis of causes of fracture of acrylic resin dentures.

The causes of midline fracture of dentures are discussed in both clinical and materials science terms. Many midline fractures can be avoided by the application of established prosthodontic principles in constructing and maintaining dentures. Improvements in the resins and processing techniques can also reduce the incidence of midline fracture. The most promising approach to preventing or reducing the incidence of this problem appears to be reinforcement in the anterior part of the palate of the denture.

The influence of percussion, occlusion and mastication on the occurrence of silent periods in masseter muscle activity.

The occurrence of silent periods in masseter muscle activity was investigated during percussion of the bony structures of the head and neck, during occlusion of the teeth on surfaces of varying hardness, and during chewing of different food-stuffs. Silent periods were demonstrated on percussion during isometric and isotonic contraction of the masseter muscles and the occurrence of silent periods was influenced by the force of occlusion and by the nature of the surface contacted. Mandibular velocity was investigated during tapping and chewing sequences by ultra-high-speed cinematography, but it was not found possible to identify a critical change in mandibular velocity associated with the occurrence of silent periods. More silent periods were observed during the chewing of hard foods than of soft foods and there were more silent periods near the beginning of chewing sequences than towards the end. Differences in latency and duration of silent periods were observed in relation to artificial changes in the occlusion.