Good occlusal practice in removable prosthodontics. (1/52)

The loss of teeth may result in patients experiencing problems of a functional, aesthetic and psychological nature. This section addresses the very important subject of occlusal considerations for partial and complete dentures. The occlusion is particularly important given the bearing that occlusal factors have, especially on edentulous patients.  (+info)

Adding silanes to MMA: the effects on the water absorption, adhesive strength and mechanical properties of acrylic denture base resins. (2/52)

The adhesive strength of porcelain artificial teeth and polymethylmethacrylates (PMMAs), which contained silanes with various number of vinyl or ethoxy groups, and the mechanical and physical properties of the PMMAs were measured. Four types of PMMAs with silanes showed high adhesive shear strength and caused fractures in the porcelain. Water absorption of the PMMAs increased with the addition of silane, but that of one type with silane was almost the same as the PMMA only type. The flexural strengths of the PMMAs with silane, except for one type, showed no significant differences compared with that of PMMA (p < 0.05). The Tg levels of all PMMAs with silane fell less than that of PMMA. From these results, it was found that PMMA with silane from three vinyl groups and one ethoxy group showed excellent chemical bonding to porcelain and low water absorption.  (+info)

Effect of artificial tooth material on mandibular residual ridge resorption. (3/52)

PURPOSE: In this 10-year longitudinal study we evaluated the amount of mandibular residual ridge resorption for 2 groups of subjects with complete dentures, one group with porcelain artificial teeth and the other with acrylic resin teeth. METHODS: One hundred and nine patients who had undergone ridge extension procedures with skin graft and prosthetic rehabilitation with porcelain or acrylic resin teeth were investigated for mandibular bone loss. Measurements were made on serial cephalograms. RESULTS: There were no significant differences between the groups in terms of their baseline characteristics (age, period of edentulousness, period of observation, vertical facial morphology, sex, severity of atrophy or presence of bruxism). Similarly, there were no statistically significant differences in amount of bone loss in relation to baseline characteristics. CONCLUSION: The view that acrylic resin teeth should be preferred to prevent bone resorption of the mandibular residual ridge is not supported by these data. Further research concerning soft denture-lining material should be undertaken to elucidate the potential role of denture pressure in ridge resorption.  (+info)

Prosthodontic rehabilitation in Papillon-Lefevre syndrome: a case report. (4/52)

Papillon-Lefevre syndrome is a rare recessive genetic disorder. The clinical manifestations include palmar-plantar hyperkeratosis with precocious rapidly progressive periodontal disease that results in premature exfoliation of primary and permanent dentitions. Patients are often edentulous at an early age. Here is the report of prosthodontic rehabilitation of a case of Papillon-Lefevre syndrome in a 6-year-old child.  (+info)

Clinical pearl In-treatment replacement of missing incisors. (5/52)

Four methods of in-treatment replacement of missing incisors are described.  (+info)

An investigation into the bonding of orthodontic attachments to porcelain. (6/52)

This study assessed bonding of orthodontic brackets to porcelain teeth using two different surface preparation techniques and comparing two bonding systems, Fuji Ortho L.C. and Transbond. Four groups of 20 porcelain premolar teeth were bonded with metal orthodontic brackets (0.022 inch Minitwin, 3M Unitek) according to the following protocol: Transbond with a phosphoric acid etch (group 1), Transbond with a hydrofluoric acid etch (group 2), Fuji Ortho L.C. with a hydrofluoric acid etch (group 3), and Fuji Ortho L.C. with a phosphoric acid etch (group 4). All groups were bonded with a silane coupling agent. The teeth were debonded with an Instron universal testing machine. Bond strength, site of bond failure and adhesive remnant index (ARI) were recorded for each group. Differences between groups were analysed statistically. The composite resin groups (groups 1 and 2) had the highest mean bond strength values at 7.9 and 9.7 MPa, respectively. The resin-modified glass ionomer cement groups (RMGIC; groups 3 and 4) had the lowest mean bond strength values at 6.3 and 1.8 MPa, respectively. The mean bond strength of group 3 was significantly lower than all other groups (P < 0.0001). The Fuji groups had also significantly (P < 0.001) lower ARI scores than the composite groups (groups 1 and 2). Most samples experienced porcelain surface damage, except group 4. In conclusion, the highest bond strength levels were achieved with a conventional composite resin cement (groups 1 and 2). No significant differences in bond strength were found between the hydrofluoric and phosphoric acid etch technique.  (+info)

Quantitative evaluation of axial wall taper in prepared artificial teeth. (7/52)

The purpose of this study was to quantitatively evaluate the axial wall taper of prepared artificial teeth using a non-contact three-dimensional shape measuring system. A total of 54 artificial teeth prepared by pre-clinical dental students for complete cast restorations were evaluated. For quantitative analysis, five cross sections were computer-graphically placed perpendicularly to the z-axis. The surface coordinate values (x, y, z) of each cross section were converted into polar coordinate values (r, theta), which were then graphically rendered to a two-dimensional plane. At four points, each 90 degrees from the distal center point of the cross section, the axial wall taper was quantitatively calculated using a formula based on the differences in radius between the highest and lowest positions of the cross sections of the prepared tooth. The average calculated taper was 5.8 degrees in the distal region, 21.7 degrees in the buccal region, 14.9 degrees in the mesial region and 12.5 degrees in the lingual region. These results suggest that the axial wall taper of prepared teeth can be quantitatively evaluated using this measuring system.  (+info)

Effect of adhesive primer developed exclusively for heat-curing resin on adhesive strength between plastic artificial tooth and acrylic denture base resin. (8/52)

Despite progress in the development of denture base resin and artificial tooth materials, dental clinics are still plagued with artificial teeth falling off the denture base--due to poor bond strength--after denture delivery. Against this background, this study sought to examine the effect and durability of an adhesive primer developed exclusively for heat-curing resin on the adhesive strength of heat-curing denture base acrylic resin to plastic artificial tooth. Test specimens were divided into four groups according to the treatment method of the artificial tooth's test bonding surface: air abrasion, adhesive primer application, adhesive primer application after air abrasion, and pretreatment only (control). After heat curing of acrylic resin onto the bonding surface, shear test was performed for two storage periods: 24-hour versus 100-day water storage. From the results obtained, it was revealed that the evaluated adhesive primer was significantly effective in increasing adhesive strength between artificial tooth and acrylic resin, although specimens were stored in water for 100 days.  (+info)