A Technique to Evaluate the Space for Retentive Components under a Removable Prosthesis.

Space analysis for retentive components is a critical part of a treatment plan for an implant-retained prosthesis. This article describes a technique to evaluate the retentive component space between the mucosa and intaglio surface of a removable prosthesis. This technique uses a silicone mold to represent the relieved space. Two silicone matrices are fabricated over the silicone space replica as a reference for selecting or fabricating retentive components for the implant-retained removable prosthesis.

Consequences of relining on a maxillary complete denture: A clinical report.

The position of a complete denture may change after relining, especially in the maxillary arch. This report reviews relining techniques and presents a situation with anterior displacement after the relining of a maxillary complete denture. Instead of providing a new denture, the displaced denture was repaired and the original tooth arrangement maintained.

The effect of autopolymerizing acrylic resin thickness on the bond strength of a repaired denture tooth.

PURPOSE: This study analyzed the conventional method of rebonding a denture tooth, evaluating the effect of varied thickness of autopolymerizing acrylic resin on the bond strength and the failure mode. MATERIALS AND METHODS: A total of 52 heat-polymerizing acrylic resin specimens were fabricated with an anterior denture tooth. A cantilever-type bending force was applied with a universal testing machine to each specimen until failure. The failure mode was determined, and cohesive failures were excluded from part II. Thirty specimens were randomly selected and divided into three groups (n = 10). For each group, resin was relieved from the bonding area to create a 0, 1, or 3 mm space. The tooth was repositioned using its matrix and reattached to its base, filling the relieved space with autopolymerizing acrylic resin. The repaired specimens were tested using the same parameters. Data were analyzed with paired t-tests, one-way ANOVA, and post hoc test. Statistical significance was determined at p < 0.05. RESULTS: The mean peak load to failure for the part I group was 88.91 N. While the peak load to failure decreased to 71.96 N (19.69% loss of original bond strength), statistical analysis revealed no difference between the bond strength of the specimens repaired with a 0 mm thickness of autopolymerizing acrylic resin and the original (part I) group (p > 0.05). The bond strength was lower for the group repaired with a 1 mm thickness compared to the original (part I) group (p < 0.05), with 65.8 N load to failure (29.63% loss). The bond strength was even lower for the group repaired with a 3 mm thickness (p < 0.05), with 58.64 N load to failure (33.07% loss). Post hoc analysis revealed a significant difference between the 0 and 3 mm groups (p = 0.04). The most common failure mode in the original group was adhesive (56%), then combination (34%), then cohesive (9.8%). The repaired group (n = 30) had similar results, with 56.7% adhesive, 36.7% combination, and 6.7% cohesive failures. CONCLUSIONS: The bond strength of a replaced denture tooth is affected by the thickness of the autopolymerizing acrylic resin. The failure mode of a rebonded denture tooth follows the same trend of the original failure. If possible, replace teeth with no relief. If combination failure occurs, leave residual base acrylic resin on the ridge lap.

A technique for improving the retention of dentures retained by ramus frame implants.

Retention for a denture on a ramus frame implant is usually less satisfactory. The friction between the frame and denture is not reliable. Locking-type attachments require manual dexterity, which could be a problem for many patients. This article presents a technique of cementing the stud-type attachments to the ramus frame to convert the retention mechanism from one that uses the friction between the acrylic resin and ramus frame to a conventional resilient precision attachment. The retention can also be adjusted by changing the nylon inserts.

A comparison of retention characteristics in prefabricated and custom-cast dental attachments.

PURPOSE: The aim of this in vitro study was to investigate the retention characteristics of attachments fabricated by machine milling or by custom casting. In addition, the retention of reduced dimension attachments was also evaluated. MATERIALS AND METHODS: Three types of ERA matrices, one prefabricated and two cast, were used. Ten specimens were made for each type, and white nylon patrices were transferred to denture bases. Tests were performed at a crosshead speed of 0.2 in/min with an Instron machine. The dislodging force at baseline, 100, 200, 300, 400, 500, and subsequently after every 500 pulls up to 2500 pulls were measured. ANOVA and Student's t-test were used to analyze the measurements. RESULTS: All three groups showed no difference at the baseline, but the cast groups showed greater variation within group. The prefabricated group showed higher retention after 200 pulls. Decreased-dimension attachments have no significant difference when compared to the cast regular dimension group after 400 pulls. CONCLUSION: The prefabricated attachments had superior retention than the cast groups over time. Reduced dimension did not reduce the retention when compared to the cast group.

Using silicone impression material and acrylic resin to fabricate remount casts for removable partial dentures.

A technique is described for fabrication of a remount cast for a removable partial denture. This procedure consists of filling the occlusal/incisal third with acrylic resin and injecting polyvinylsiloxane impression material into the irreversible hydrocolloid impression. This technique provides a simple method for making a remount cast and enables the clinician to remove and easily place the partial denture on the cast during occlusal refinement procedures without damage to the removable partial denture or the remount cast.