Prospective evaluation of immediate and delayed provisional single tooth restorations.

PURPOSE: The purpose of this study was 2-fold: to determine whether there is a significant difference in the hard and soft tissue response comparing immediate with delayed implant placement after tooth removal, with immediate provisionalization, in maxillary anterior sites; and to determine and compare the crestal bone levels as the primary endpoint variable for implants placed and immediately temporized in extraction sites, to implants placed into extraction sites after the extraction site has been grafted and healed for 4 months, all immediately restored with an anatomic provisional restoration. This aim was to be evaluated by measuring crestal bone levels on standardized digital radiographs of the implants, using implant threads as a monitor of magnification and a pre-extraction reference. Secondary endpoint variables include soft tissue measures compared with method. MATERIALS AND METHODS: A total of 76 patients were recruited and randomized into treatment groups. Group 1 had a maxillary tooth (premolar, canine, lateral or central incisor) removed, with immediate socket grafting, followed by implant placement and provisionalization 4 months later with a single tooth. Group 2 had immediate implant placement and provisionalization. Standardized radiograph holders were used to expose digital radiographs every 6 months from baseline to up to 2 years restored. Soft tissue measures were made from standardized reference points. Data collected were analyzed by a statistician to test the hypotheses. RESULTS: A total of 55 patients completed their follow-up. Twenty-one patients were lost to follow-up because of implant loss (n = 5), 1 treated out of protocol because of labial bone loss found at the time of tooth removal (n = 1), geographic relocation (n = 11), dropped for noncompliance (n = 3), or medical problems (n = 1). The analyses showed no significant differences between groups in implant integration or crestal interdental bone movement on either the implant or the adjacent tooth. The bone level on the implants did move from the baseline levels during the first 6 months but not thereafter. There were no differences (P > .05) observed when comparing the interactions between groups, tooth locations, or time. There was a significant (P < .05) difference in the position of the facial gingival margin with a more apical position of the facial gingival margin in the delayed group compared with the immediate group during the course of the study. CONCLUSIONS: Crestal bone response to immediate or delayed placement of an implant into an extraction site in the maxillary anterior region with immediate provisionalization is similar regarding hard tissue changes. Support of the gingival margin with a provisional at the time of tooth extraction and implant placement preserved 1 mm more facial gingival margin position compared with the delayed group. The decision to use either method must consider the movement of the facial gingival margin, which, in a critical esthetic patient may require soft tissue support from a provisional restoration or similar type of anatomical healing abutment.

Prospective evaluation of implants connected to teeth.

PURPOSE: This prospective clinical trial examined the effect on teeth and implants when rigidly or non-rigidly connected in a cross-arch model. MATERIALS AND METHODS: Thirty patients received 2 implants, 1 on each side of the mandible, and were restored with 3-unit fixed partial dentures connected either rigidly or non-rigidly to an abutment tooth. Patients were followed for at least 5 years post-restoration. RESULTS: Repeated-measures analysis revealed no significant difference in crestal bone loss at implants (rigid versus non-rigid methods). An overall significant difference (P < .001) was found comparing methods for teeth. Paired t tests revealed no significant differences in crestal bone levels for implants or teeth at the 5-year recall. Kaplan-Meier methods and the Cox proportional hazards model showed no differences between attachment methods with regard to success based on survival and bone loss criteria. During the 5-year recall period, 1 implant (rigid side) was removed. Four implants developed bone loss greater than 2 mm during the course of this trial. One tooth on the rigid side and 2 teeth on the non-rigid side had greater than 2 mm of crestal bone loss and were removed secondary to fractures. In all, 5 abutment teeth were removed, all of which had been treated with root canal therapy and fractured at the interface of the post within the tooth. There was no clear relationship of tooth fracture to attachment. Repeated-measures analysis of mobility values revealed no significant changes over the time course of this study, and paired t tests revealed no statistically significant differences between implants for mobility. Repeated-measures analysis and paired t tests for probing depth revealed no significant changes over the time course of this study. There were no significant differences in soft tissue indices for either attachment method. The percentage of patients who had measurable intrusion was 66% for the non-rigid group, and 44% for the rigid group; 25% of the non-rigid teeth had greater than 0.5 mm intrusion, compared with 12.5% for the rigid group. For the 2 time periods evaluated, there was no significant increase in intrusion over time. The non-rigid-side implant required more nonscheduled visits to treat problems than the rigid implant and the teeth. DISCUSSION: Most patients were treated successfully with rigid or non-rigid attachment of implants to teeth. CONCLUSION: The high incidence of intrusion and non-scheduled patient visits suggest that alternative treatments without connecting implants to teeth may be indicated.