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At least 415 records · Page 23Linked to original sources
PubMed2006

Selection of appropriate artificial frontal teeth size using dimensions of hard palate.

Eighty dentate students participated as a study group and another 74 as a control group. The aim was to determine a possibility to reconstruct maxillary frontal teeth dimensions by use of certain hard palate dimensions. The height (IH) and the incisal (IW), contact point (CtW) and cervical width (CW) of maxillary central incisors (MCI), hamular width (HW) and the distance between the incisive papilla and the palatine foveas (IP-FP) were measured on the maxillary casts. CtW of maxillary lateral incisors and canines were measured too. In the study group the ratios were computed: HW/IW (5.71), HW/CtW (5.69), HW/CW (5.51) and IP-FP/IH (4.76). These ratios were multiplied by incisor's dimensions (obtained from the control group) to calculate the hard palate dimensions. No significant differences were obtained between the calculated and the measured (study group) hard palate dimensions. Furthermore, there was no significant difference between the HW and the Sum of contact-point widths of all maxillary frontal teeth (p > 0.05) in the both groups. The results revealed: 1. MCI width and height might be calculated by dividing dimensions of a patient's hard palate and appropriate ratio; 2. hamular width dimension can be used as a selection guide for the sum of contact-point widths of six maxillary frontal teeth.

Adult↗
PubMed1985

Determining approximate size of maxillary anterior artificial teeth when mandibular anterior teeth are present. Part I: Size relationship.

Three methods were used to obtain a ratio of the maxillary to the mandibular anterior teeth, with results of 1.29, 1.30, and 1.31. It can be concluded that a ratio of 1.30 is sufficient to determine the approximate width of the six maxillary anterior teeth when given the size of the mandibular natural anterior teeth. This ratio should be valid to select a maxillary denture mold of sufficient width mesiodistally to obtain a Class I canine relationship. However, the ratio may need a slight adjustment to compensate for the intentional disocclusion of the maxillary denture teeth with the natural mandibular teeth. In Fig. 1 the canine to canine measurement of the mandibular anterior teeth was 35 mm; when multiplied by a factor of 1.30, a maxillary measurement of 45.5 mm is obtained. The denture teeth were to be set with approximately 1 mm of horizontal overjet and 1 mm of vertical overlap (Fig. 2), therefore a slightly larger mold of 48.5 mm was chosen (Fig. 3). This maxillary mold produced a Class I canine relationship (Fig. 4). The 48.5 mm ratio of the chosen maxillary mold to the mandibular measurement of 35 mm yielded a ratio of 1.38. When this ratio of 1.38 is applied, the desired prosthetic mold is not always available. There is a range of acceptability above and below the desired ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Cuspid↗
PubMed2002

Frequency and costs of technical failures of clasp- and double crown-retained removable partial dentures.

OBJECTIVES: The aim of this study was to evaluate the frequency of technical failure rates and the maintenance costs of clasp- or double crown-retained removable partial dentures (RPDs) (parallel-sided and conical double crowns). MATERIAL AND METHODS: According to three different retainer systems used between January 1992 to December 1998, three subgroups were randomly assigned from a group of 181 patients consisting of forty cases each. The average observation time was 4.2+/-1.7 years, with a minimum of 1.0 years and a maximum of 6.9 years. Technical complications such as fractures of the artificial teeth, loss of cementation, loss of facings as well as fractures of the metal framework and the soldering were recorded due to the medical reports. RESULTS: Twenty percent of all clasp-retained dentures showed technical complications during the observation period, whereas 50% of conical crown-retained (CC) and 32.5% of the parallel-sided retained dentures (PS) required repair. Most often reported was loss of cementation for double crowns (n=13, 32.5% PS; n=8, 20% CC) and fractures of the clasps (n=5). Although clasp-retained dentures had a markedly lower frequency of failures (n=8) than double crown systems (n=31), the calculated repair costs per event during the observation time were more than twice as high for clasp-retained dentures (172.5 Euro) than for double crown systems (8-78 Euro). The hypothesis that the maintenance costs of the more sophisticated double crown system are higher must be rejected.

Acrylic Resins↗
PubMed1997

Comparative in vitro effectiveness of closed root debridement with fine instruments on specific areas of mandibular first molar furcations. II. Furcation area.

The purpose of this study was to demonstrate the extent of deposits removed from within the furcation area of mandibular first molars following the use of curets with a modified blade and slim ultrasonic inserts in an in vitro model simulating a closed root debridement approach to furcation treatment. The furcation areas of 100 artificial mandibular first molars were uniformly coated with black model paint. The molars were fixed into a custom acrylic model, maintained in a firm position with modified occlusal splints, and the roots covered with a heavy rubber dam. The model was set in a mannequin and mounted on a dental chair recreating a clinical situation. Fifty molars (25 right, 25 left) were instrumented with the experimental curets and an equivalent number of molars with the ultrasonic inserts. An experienced dental hygienist completed all the instrumentation, spending 4 minutes on each molar. The molars were sectioned buccolingually from the crown apically to separate the roots, and areas in the internal surface of mesial and distal roots were analyzed to determine the percentage of deposits remaining using a computerized imaging routine system. A 2-factor analysis of variance was conducted to test for differences between both types of instruments. The curets produced furcation root surfaces with significantly less percentage of residual deposits than the ultrasonic inserts (P < 0.01). This study indicates the potential value of small bladed curets in debriding involved furcations during initial therapy and supportive periodontal therapy. The current findings should be corroborated in a clinical study.

Acrylic Resins↗
PubMed1997

Comparative in vitro effectiveness of closed root debridement with fine instruments on specific areas of mandibular first molar furcations. I. Root trunk and furcation entrance.

The purpose of this study was to compare curets with a small blade to slim ultrasonic inserts on their efficacy in removing artificial deposits from the root trunk and furcation entrance areas of mandibular molars using an in vitro model simulating a clinically closed root debridement approach. The study was conducted on 100 artificial mandibular first molars (50 right side and 50 left side) with anatomical roots. Root trunks, furcation entrances, and furcation areas of each molar were colored by a coat of black model paint. The teeth were fixed in a custom acrylic model and maintained in a firm position by modified acrylic occlusal splints. The root areas were covered with a heavy rubber dam imitating gingival tissue. The model was attached to a mannequin and mounted on a dental chair. Fifty molars (25 right, 25 left) were instrumented with the experimental curets and an equivalent number of molars with the ultrasonic inserts. The instrumentation was carried out by one experienced operator, spending 4 minutes on each molar. The instrumented areas were individually analyzed to determine the percentage of deposits remaining, using a computerized imaging routine system. One-way analysis of variance was conducted to test for differences between both types of instruments. Results revealed that the curets were significantly more efficient (P < 0.01) than the ultrasonic inserts in removing paint from both root trunks and furcation entrances. These findings should be corroborated in a clinical study to determine the potential value of the instruments tested during initial therapy or supportive care of involved mandibular furcations.

Acrylic Resins↗
PubMed1998

Linear dimensional change of heat-cured acrylic resin complete dentures after reline and rebase.

STATEMENT OF PROBLEM: Relining and rebasing of complete dentures are common procedures to improve the fit of the prostheses. After relining or rebasing, adjustments may be required because of dimensional change that occurs during reprocessing of the denture when new denture base material is polymerized. PURPOSE: This study analyzed the linear dimensional change of heat cured acrylic resin that occurs during reline and rebase procedures for complete dentures. MATERIAL AND METHODS: Twenty-two maxillary and mandibular complete denture bases with artificial teeth were saturated by immersion in distilled water at 37 degrees C +/- 1 degree C. Fine crosses were marked on the incisal edges of the central incisors and the supporting cusps of the second molar teeth. Distances between the marks were measured with a high resolution traveling microscope. Heat-cured acrylic resin was processed by a long curing cycle of 72 degrees C for 6.5 hours, then heated to 100 degrees C for over 30 minutes and kept at 100 degrees C for 1 hour. The relined or rebased denture was allowed to cool slowly in the water bath for 48 hours to reach ambient temperature. The reference-crosses were measured immediately after careful deflasking. RESULTS: In the relining procedure, all incisor-molar and intermolar distances exhibited shrinkage of 0.3%, despite different shapes of maxillary and mandibular dentures. Results of the rebasing procedure were similar to that of the reline expect that only 0.1% intermolar shrinkage was found on the maxillary denture. CONCLUSION: Shrinkage was approximately 0.15 mm for an interarch distance of 50 mm. This degree of change is both clinically undetectable and insignificant. Using this processing cycle for acrylic resin in reline or rebase procedures did not cause clinically significant dimensional changes to complete dentures.

Acrylic Resins↗
PubMed2004

Extraction sockets and implantation of hydroxyapatites with membrane barriers: a histologic study.

The purpose of this pilot study was to investigate the effect on extraction socket healing when an absorbable hydroxyapatite (AH) and a nonabsorbable anorganic bovine bone mineral (ABB) covered with either an acellular dermal matrix allograft (ADMA) or expanded polytetrafluoroethylene (ePTFE) membrane barrier were left exposed to the oral cavity. Following tooth extraction, a total of 16 sockets in 15 patients with deficient buccal plates of > or =5 mm were randomly divided into 4 treatment groups: 1) AH covered with ADMA, 2) AH covered with an ePTFE membrane, 3) ABB covered with ADMA, and 4) ABB covered with an ePTFE membrane. Primary coverage was not attempted or obtained in any of the 16 treated sockets. Six to 8 months postextraction at the time of implant placement, histologic cores of the treatment sites were obtained. These cores were processed, stained with Stevenel's blue/van Gieson's picro fuchsin, and histomorphometrically analyzed. Vital bone, connective tissue and marrow, and residual graft particles were reported as a percentage of the total core. The mean vital bone was 34.5% (AH with ADMA), 41.7% (ABB with ADMA), 27.6% (ePTFE and AH), and 17.8% (ePTFE and ABB). The average percentage of vital bone in the 8 sockets covered with ADAMA was 38% compared with an average percentage vital bone of 22% in the 8 sockets covered with ePTFE membrane barriers. Because of the small number of specimens in the 4 groups, statistical analysis was not possible. However, in this pilot study, ADMA-covered sites resulted in more vital bone present 6 to 8 months postsocket treatment than obtained in the ePTFE-covered sites regardless of bone replacement materials used. Further research is warranted to see if these results show a similar difference in bone-to-implant contact after implant placement.

Adult↗
PubMed2000

In vitro colonisation of acrylic resin denture base materials by Streptococcus oralis and Actinomyces viscosus.

AIM: The aim of the study was to compare the attachment of two typical strains of oral bacteria to four denture base materials. DESIGN: In vitro study. METHOD: Discs of acrylic resin denture base materials (Paladon 65, polished and unpolished; Palapress; Microbase, polished and unpolished, and Triad VLC) were placed into Petri dishes with Schaedler's medium, inoculated with Streptococcus oralis 34 or Actinomyces viscosus T14V. MAIN OUTCOME MEASURES: After 24 h or 48 h the numbers of adhering bacteria were measured. RESULTS: The bacteria adhered to all discs in similar numbers: 3-9 x 10(6)/ml (viable cell count) and 9-22 x 10(8)/ml (total cell count) for T14V, and 2-6 x 10(6)/ml (viable cell count) and 1.5-3 x 10(8)/ml (total cell count) for 34. CONCLUSIONS: Polishing had little effect on adherence. Denture base materials are not resistant against adherence and possible surface damage by oral bacteria. Therefore, thorough oral hygiene is important for denture wearers.

Acrylic Resins↗
PubMed1975

Use of PMMA in expansion dental implants.

The Polymer Expansion Implant System, which is a system for the substitution of missing dental roots in natural or surgical alveolus, has been developed by the author. The polymer used is poly (methyl methacrylate) (PMMA). A material is sought that has three of the basic physical and mechanical qualities of human dentine: low modulus of elasticity, thermal and electrical passiveness, and ideal porosity. In addition it should be resistant, easily worked, biocompatible, and of low cost. Of the biomedical polymers, PMMA has these qualities, and it can be used as a substitute for dental roots. The design of bodies to be implanted as substitutes for dental roots requires: anatomical measurements of the maxilla and sockets; methods of retention by the bone tissue; and methods of insertion. The formation of lamina dura around an implanted body is a reply of the organism to the forces acting on it and a demonstration of the good interaction of the porosity of the material, the peri-implant collagenous fibers and bone. X-rays that demonstrate the behavior of bone to a PMMA implant are shown.

Alveolar Process↗
PubMed1975

Porous, heat cured poly (methyl methacrylate) for dental implants.

The use of polyl (methyl methacrylate) for tooth replica implants, as developed by Hodosh, is described as to indications, ingredients, and fabrication technique. Laboratory testing of this material for mechanical and thermal expansion properties, and porosity content were determined as a function of foaming agent and and anorganic bone particle content.

Animals↗