A quantitative evaluation of the distal displacement of the gingival zenith in the maxillary anterior teeth.

The aim of this study was to quantify the specific distal displacement of the gingival zenith in the maxillary anterior dentition. Bilateral measurements, taken with a digital caliper in maxillary stone casts were recorded in six maxillary anterior teeth to evaluate distal displacement of the gingival zenith in relation to the long axis of the crowns. The gingival zenith was distally displaced between 0.45 and 1.01 mm in 90%, 85% and 60% of the central incisors, lateral incisors and canines, respectively. Contralateral comparisons between the tooth groups revealed significantly larger distal displacement of the zenith in left canine (p < 0.05). Ipsilateral comparisons revealed that the lateral displacement of the zenith was significantly larger in central than in lateral incisors (p < 0.05). Similarly, the zenith of lateral incisors was displaced significantly more distal than that of canine teeth (p < 0.05). Comparisons of the frequency of coincidence of the position of the gingival zenith with the long axis of the tooth revealed that it was significantly greater in canines than in lateral and central incisors (p < 0.05). The frequency and magnitude of distal displacement is tooth-dependent and larger in central than in lateral incisors, which in turn, is larger than in canines. These data could be used as reference points during esthetic anterior oral rehabilitation, especially in case of porcelain laminate veneers.

Comparative study of condylar inclination settings in two types of semiadjustable articulators.

The purpose of this study was to research the possible influence of difference in construction of mechanical joint in arcon and nonarcon articulators, upon the adjustment of condylar inclination by intraoral protrusive record. The determination of condylar inclination by protrusive record in two types of articulators was performed on 30 examinees, and the adjustment of condylar inclination in each articulator was done for left and right joint. In arcon articulator the measured values for condylar inclination were higher and the mean difference for right joint was 7.4 degrees, and for the left joint 7.2 degrees The found differences are statistically significant for both, left and right joint, at the level of P < 0.001. There is possible influence of difference in construction of mechanical joint upon the adjustment of condylar inclination by intraoral protrusive record. The arcon articulator, due to constant relation between occlusal plane and mechanical fossa, reproduces the movements more accurately.

[Custom-made mouthguards and prevention of orofacial injuries in sports]. / Individualni sportski stitnik za zube i prevencija orofacijalnih sportskih ozljeda.

The importance of sports dentistry has become even greater due to the role that sports have in modern society. As the risk of sports-related injuries appears already in the period of children's play and is constantly present in various risk-related sporting activities, the role of dental profession has become extremely important. Custom-made mouthguards are the most highly recommended mouthguards used for successful prevention of orofacial and dental injuries. It is important to inform athletes of the best characteristics of a custom-made mouthguard such as retention, comfort, fit, ease of speech, resistance to tearing, ease of breathing as well as good protection of the teeth, gingiva and lips. The shape and surface of the mouthguard which encloses the teeth, the gingival and the hard palate can vary depending on the anatomical features of the athlete's jaw, his/her dental arch, the type of sports activity, as well as the materials used in the manufacture of the mouthguard. Mouthguards should not extend distally further than the first molars because some athletes complain of the vomiting reflex. In addition, mouthguards may interfere with breathing. They should reach the mucogingival border labially and extend a few millimeters palatally in order to provide the best protection for the labial gingival and good retention. The labial flange should extend up to 2 mm of the vestibular reflection. The palatal flange should extend about 10 mm above the gingival margin thus enclosing the greatest part of the anterior palate surface with a slight narrowing distally not further than the first molars. Materials used in the manufacture of mouthguards should satisfy a number of physical, mechanical and biological requirements. Essential properties of materials used in the manufacture of mouthguards include water absorption, density, thickness as well as temperature transmission, energy absorption and drawing strength (tensile strength) of custom-made mouthguards. Such materials should have an optimal consistency in order to cushion the traumatic impact. Currently, ethylene-vinyl acetate (EVA) is the most commonly used mouthguard material. An optimal thickness of the mouthguard is achieved by the application of vacuum forming pressure-lamination technique in two layers of a thermoplastic sheet of EVA copolymer and if needed, by placing two layers of protective air-cells against the critical area. Some investigations in the Croatian samples showed that the most common injuries in water polo occur in the orofacial region (96.4% of cases), of which 80% are injuries of lips, tongue and cheek. In the period from 1997 to 2005 the number of orofacial injuries increased by 62%. Dental trauma occurs in 7.6% of cases. In basketball players soft tissue injury in the orofacial complex was established in 69.4% and dental trauma in 11.3% of the respondents. In the selected sample of handball players, soft tissue injuries were established in 78.8%, dental trauma and loss of teeth in 13.6% and temporomandibular joint injuries in 6.8% of the cases. In tae-kwon-do players 88% of orofacial injuries were lacerations, but only 12% reported dental and temporomandibular joint trauma. Only a half of the examined professional basketball players wore mouthguards, and none of the examined tae-kwon-do players. Clinical value of intraoral custom-made mouthguards was proven. Dentists play the key role in the prevention and treatment of sports-related dental and orofacial injuries, collection and dissemination of relevant information, as well as promotion of research on the preventive procedures related to injuries of such a specific aetiology.

Factors related to patient satisfaction with complete denture therapy.

BACKGROUND: Except for denture quality, many other factors are related to a patient's satisfaction with complete dentures (CDs). METHODS: A total of 222 patients with CDs took a part in this study. A questionnaire divided into 3 parts was completed by both the patients and the dentist, independently. The patients rated their dentures using a scale ranging from 1 to 5 (1 = dissatisfaction to 5 = excellent), and a dentist rated the quality of the denture and the denture-bearing area. RESULTS: Patients were mostly satisfied with the quality of their CDs. Only 7.2% of the patients were absolutely not satisfied with their dentures. Patients with a low level of education were more satisfied in general with their aesthetic appearance. Patients with better self-perception of their affective status and quality of life showed higher levels of general satisfaction. Patients with better self-perception of their economic status showed lower levels of satisfaction. Younger patients wearing dentures for the first time, with short periods of being edentulous, and with better quality maxillary denture-bearing areas were more satisfied with the retention of maxillary CDs. In contrast, younger patients with first-time dentures, a short period of being edentulous, and with better quality mandibular denture-bearing areas gave lower ratings to the retention and comfort of wearing mandibular dentures. CONCLUSIONS: Level of education, self-perception of affective and economic status, and quality of life are all related to patient satisfaction. However, the quality of dentures shows the strongest correlation with patient satisfaction. Not only the quality of the denture-bearing area but the denture-wearing experience itself seems to be more important in determining patient satisfaction with mandibular CDs.

A 3D visualization and simulation of the individual human jaw.

A new biomechanical three-dimensional (3D) model for the human mandible based on computer-generated virtual model is proposed. Using maps obtained from the special kinds of photos of the face of the real subject, it is possible to attribute personality to the virtual character, while computer animation offers movements and characteristics within the confines of space and time of the virtual world. A simple two-dimensional model of the jaw cannot explain the biomechanics, where the muscular forces through occlusion and condylar surfaces are in the state of 3D equilibrium. In the model all forces are resolved into components according to a selected coordinate system. The muscular forces act on the jaw, along with the necessary force level for chewing as some kind of mandible balance, preventing dislocation and loading of nonarticular tissues. In the work is used new approach to computer-generated animation of virtual 3D characters (called "Body SABA"), using in one object package of minimal costs and easy for operation.