Fit of the removable partial denture base and its effect on abutment tooth movement

The effect of the fit of a partial denture base on abutment tooth and denture base movement was tested under controlled laboratory conditions. Even with the most accurately fitted base, the partial denture moved when it was loaded. The fit of the partial denture affected both the direction and the magnitude of abutment tooth movement.     

Intentional replantation of a removable partial denture abutment tooth: a case report.

Intentional tooth replantation is a last-resort procedure, recommended only when all other techniques, short of tooth extraction, have been exhausted or are impractical. Although most endodontic textbooks describe the procedure, and many reports of intentional replantation have appeared in the dental literature, none have reported use of the technique to retain a removable partial denture abutment tooth. This article presents such a case and the rationale for the decision to intentionally replant. Eighteen-month follow-up clinical and radiographic results are presented.     

Significance of abutment tooth angle of gingival convergence on removable partial denture retention

The angle of gingival convergence is one of the many factors that influence the retention capability of removable partial denture clasps. A geometric evaluation of the retention properties of this angle has been presented.     

Replacing an abutment crown for an existing removable partial denture

A method to replace an abutment crown for an existing removable partial denture has been presented.     

Provisional restoration for abutment of an existing removable partial denture

The abutment of an existing removable partial denture may require a crown restoration. Fabrication of a provisional restoration to fit the existing clasp assembly requires special consideration. This article presents a simple technique for fabrication of such provisional restorations. An alginate impression is made of the arch with the removable partial denture in place. The abutment tooth is then prepared, providing adequate clearance between the clasp assembly and the tooth preparation. Cold curing acrylic resin of proper shade is mixed and poured in the impression of the abutment tooth. The impression is then seated in the mouth and removed before the acrylic resin is completely polymerized. The provisional restoration is then separated from the partial denture, finished and polished.     

Lateral forces exerted on the abutment tooth of complete mandibular overdentures

The purpose of this study was to analyse the magnitude and direction of lateral forces exerted on the abutment tooth of a complete mandibular overdenture. A newly developed transducer was used for measuring forces. It was small enough to be embedded in the lower denture base, and could detect the magnitude and direction of forces. Five subjects, 38 to 77 years of age, with an edentulous maxilla and one or two canines remaining in the mandible were selected for this experiment. An upper complete denture and a lower complete overdenture with only one abutment tooth were fabricated for each subject. Forces exerted on the abutment tooth were measured during tapping and chewing of kamaboko (a Japanese cooked fish paste with soft consistency) and also peanuts, a few days and about 20 days after the denture insertion. The following results were obtained: (i) the average magnitude of lateral forces ranged from 0.5 to 2.0 kgf, and there were significant differences of the mean value between subjects; (ii) lateral forces were mainly observed on an imaginary line drawn through the experimental tooth (lower canine) and the opposite retromolar pad. There were no significant differences between the first and the second measurement.     

Effect of abutment tooth reinforcement techniques on the fracture resistance of removable partial denture master casts

PURPOSE: The purpose of this study was to compare the mean loads required to fracture an isolated stone abutment tooth when various reinforcement techniques were used: (A) no reinforcement, (B) surface hardening, (C) impression trimming, (D) dowel placement, and (E) impression trimming plus dowel placement. MATERIALS AND METHODS: Die stone premolar specimens for each group (n = 4) were loaded perpendicular to the tooth long axis in 100-g increments 25 hours after pouring the impression. Mean load to failure was determined for each group. Data were evaluated with a one-way analysis of variance (alpha = 0.05) to determine differences among groups. Paired comparisons of factor level means were made with Tukey's q-test. RESULTS: The mean fracture load for Group E (7.6 kg) was significantly greater than Groups A (2.0 kg), B (2.1 kg), and C (3.4 kg). No significant difference was found between Groups D (6.0 kg) and E. CONCLUSIONS: Dowel reinforcement with impression trimming at the cervical portion of the abutment tooth resulted in significantly greater fracture resistance than the control, surface model hardener, or impression trimming alone. J Prosthodont 2001;10:22-25.     

Single tooth replacement with a removable partial denture

The indication of removable partial dentures in cases of single tooth replacement is limited. This is due to a number of disadvantages closely connected to the use of removable partial denture. An often applied use is that of a mucosa-borne transitional acrylic denture to improve patients aesthetics until the definitive denture can be made. Acrylic dentures may be indicated as a definitive denture when limited financial resources are available. A metal frame removable partial denture can be applied to lengthen a shortened dental arch or in specific cases in which fixed partial dentures are not the preferable treatment option. The success of the treatment with a removable partial denture is highly dependent on the follow-up service and the oral hygiene awareness.     

制作适合原有可摘局部义齿的基牙全冠的临床方法

目的：研究制作适合原有可摘局部义齿的基牙全冠的修复方法。方法：采取间接法制作基牙全冠，即在备牙后制取模型，并留下可摘局部义齿在技工室制作全冠。结果：做冠后，可摘局部义齿的支托与全冠紧密贴合，卡环固位良好，患者对修复效果表示满意。结论：对于需要制作基牙全冠的病例，应该依据基牙外形保存情况、牙列缺损部位的不同，选择最佳的修复方法。     

Longitudinal clinical evaluation of undercut areas and rest seats of abutment teeth in removable partial denture treatment

Purpose: Adequate preparation of abutment teeth for removable partial denture (RPD) rest seats allows appropriate masticatory force transmission, retention, and stability of supporting structures. It follows that careful preparation will be important for the longevity of the rehabilitation. The present study aimed to clinically evaluate rest seats and undercut areas of abutment teeth in RPD wearers after 2 years of use. Materials and Methods: A total of 193 occlusal, incisal, and cingulum rest seats were evaluated in terms of shape, rest adaptation, wear, caries, fractures, and surface type (enamel, composite resin, or amalgam). Two hundred and fourteen undercut areas were evaluated in terms of surface type (enamel or restoration) and integrity. This study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, resolution 196/1996, protocol number 11/05. Results: Intact preparations accounted for 92.2% of the total. Application of the Pearson test (p= 0.289) found no statistically significant differences among the materials on which the rest seats were prepared. For the undercut areas, 20.7% of those obtained on restorative material were nonintact. In addition, Fisher's exact test showed a statistically significant difference (p= 0.001) in surface type; enamel surfaces were shown to be 14 times more stable than restored surfaces. Conclusions: The results of this study suggest that rest seats are stable, regardless of the material on which they are prepared. Retentive areas were shown to be more stable when they were located in enamel.     

Longitudinal study on torque transmitted from a denture base to abutment tooth of a distal extension removable partial denture with circumferential clasps

Not only forces but also torque exerted on abutment teeth are important factors for planning the construction of distal extension removable partial dentures. The purpose of this study was to make longitudinal analysis of torque transmitted from denture base to a direct abutment tooth of these dentures with circumferential clasps. The results are summarized as follows: (i) Vertical Max. MT (maximal mean value of torque) was decreased and became constant after one or one and half months of the insertion of new dentures. (ii) Lateral Max. MT in one subject was changed from the lingual direction to the buccal direction while in another subject it was constant. (iii) In the vertical direction, there were no remarkable differences of Max. MT and Ave. T (average value of torque) between subjects. Max. MT was 5-10 x 10(-3) kgm-1 in the downward. Ave. T was 2-3 x 10(-3) kgm ss-1 in the downward and 0.3 x 10(-3) kgm ss-1 in the upward. (iv) In the lateral direction, there were considerable differences of Max. MT and Ave. T between subjects. Max. MT was less than 20 x 10(-3) kgm. Ave. MT was 2-8 x 10(-3) kgm ss-1.     

Clinical evaluation of removable partial denture rest seat adaptation

The clinical relationship between the removable partial denture cast occlusal rest and the corresponding rest seat was examined. Under the conditions of the study, it was found that rests of mandibular Class I and II removable partial dentures fit significantly better than those of mandibular Class III and IV prostheses. No significant difference was noted between similar types of maxillary removable partial dentures in this regard. In evaluating the fit of specific portions of the occlusal rest, it was found that the marginal ridge zone was more closely adapted to the rest seat than other zones for all types of removable partial dentures. However, contact, as defined in this analysis, was found to exist on a random basis in all four quadrants of the occlusal rests evaluated. In spite of this fact, one fifth of the occlusal rests did not contact the opposing rest seat at any point. Improved fit with length of service was not substantiated by a cross-sectional analysis. Suggestions were made to assist the clinician in achieving a better fit between the framework and dentition in removable partial dentures.