Adjacent Implant-Supported Restorations in the Esthetic Zone: Understanding the Biology

Four-unit fixed dental prostheses replacing the maxillary incisors supported by two narrow-diameter implants - a five-year case series

OBJECTIVES

(1) To determine the survival rate of 10 four-unit fixed dental prostheses (FDPs) replacing the four maxillary incisors, supported by 20 narrow-diameter implants (NDIs), (2) to assess the incidence of mechanical and biological complications, and (3) to evaluate bone level changes longitudinally after final FDP insertion.

MATERIALS AND METHODS

Ten patients (six women, four men), mean age 49.4 ± 12.6 years, were treated with a four-unit anterior maxillary FDP (six screw-retained; four cemented). Biological parameters, eventual technical complications, radiographic measurements, and study casts were assessed at 1 (baseline), 3, and 5 years after implant placement. A multilevel logistic regression test was performed on clinical parameters and bone level changes (significance level P < 0.05).

RESULTS

The 5-year implant and FDP survival rate was 100%. Mean modified plaque index (mPI) values were 0.03 and 0.02 at 3 and 5 years, significantly lower when compared to mPI (0.11 ± 0.31) at 1 year. Mean modified sulcus bleeding index (mSBI) was 0.08, 0.08, and 0.15 over time. Probing depth (PD) values were 1.57, 1.64, and 2.03 mm. Statistically significant differences were found between 1 vs. 5 year (P = 0.0003) and 3 vs. 5 year (P = 0.001). Keratinized mucosa (3.65 mm) remained stable during observation period. DIB mean values were 2.01 ± 0.34, 2.13 ± 0.13, and 2.17 ± 0.38 mm. Patient satisfaction based on visual analog scale revealed favorable fulfillment of overall treatment and esthetic expectations.

CONCLUSIONS

Two NDIs supporting a four-unit FDP to replace the four missing maxillary incisors may be considered a predictable treatment modality.

Immediate nonfunctional loading of NobelPerfect implants in the anterior dental arch in private practice--5-year data

BACKGROUND

The concept of scalloped implants to maintain the natural contour of the alveolar ridge has been a source of controversy for many years.

PURPOSE

This study examined the long-term clinical performance of the scalloped NobelPerfect implant in a one-stage procedure (immediate loading in the esthetic zone).

MATERIALS AND METHODS

In 20 patients, immediate prosthetic restorations were placed on 31 NobelPerfect implants in a private practice and followed for up to 78 months. Twenty-one implants were placed immediately after extraction, seven implants were placed after osseous consolidation of the extraction sockets, and three implants were placed secondary to extended alveolar ridge augmentation procedures. All implants were provisionalized on the day of implant placement and adjusted to clear all contacts in centric occlusion and during eccentric movements. Outcome variables were success rates, marginal bone levels, and pink esthetic score (PES) assessed per implant.

RESULTS

One implant failed after 1.4 months. Five patients with six implants in total were scored in the 5-year follow-up as dropouts. Mean follow-up period of remaining 24 implants was 65 months (range, 55-78 months). Cumulative success rates according to the criteria specified by Smith and Zarb were 96.8%. Marginal bone levels averaged 1.1 mm above the first thread. Mean PES ratings were 10.5 (range, 3-13).

CONCLUSIONS

Survival rates, marginal bone levels, and esthetic results suggest proof of principle for the preservation of the interproximal bony lamella with a scalloped implant design in long-term data.

Scalloped Dental Implants: A Retrospective Analysis of Radiographic and Clinical Outcomes of 17 NobelPerfectTM Implants in 6 Patients

BACKGROUND

The scalloped dental implant (NobelPerfect, Nobel Biocare, Yorba Linda, CA, USA) is designed to biologically guide and facilitate interproximal bone remodeling during healing and to maintain bone height and papillae during functional loading. The design features of the scalloped implant include hard and soft tissue apposition areas, which are parallel to each other and mirror the cementoenamel junction. The hard tissue surface area is intended for osseointegration. The soft tissue surface area is meant to support the connective tissue zone and to provide a space for the subgingival margin of the restoration. Current literature on the clinical performance of the scalloped dental implant is limited.

PURPOSE

The aim of this study was to evaluate whether the scalloped dental implant maintains interproximal bone and the overlying soft tissue.

MATERIALS AND METHODS

Radiographs for six patients (mean age 40.5 years) treated with 17 implants (NobelPerfect) were reviewed for an 18-month follow-up evaluation of bone response. Orthodontic movement and/or autogenous bone augmentation had been provided to obtain the best possible soft and hard tissue dimensions prior to implant placement. A surgical guide was used for an optimal implant placement. No surgical flap was reflected, and implants were placed a minimum of 2 mm and a maximum of 3 mm apical (midbuccally) to the most apical portion of the surgical guide. Final optimal rotational alignment was achieved in all cases by not exceeding 45 Ncm. Implants were immediately restored with provisional crowns. Photographic documentation provided the basis for analysis of papillary response. Radiographic change in the interproximal bone level was obtained by computer analysis (ImageJ for Windows, National Institutes of Health, Bethesda, MD) by measuring the distance from the interproximal shoulder of the scalloped implant to the crest of the bone.

RESULTS

When the scalloped implants were placed adjacent to existing natural dentition, the average bone level at placement and at 6, 12, and 18 months was -1.7, -3.5, -3.8, and -3.9 mm, respectively, compared with -1.0, -3.6, -4.3, and -4.4 mm respectively, when placed adjacent to other scalloped implants. Papillae formation exhibited no differences from the configuration that typically results after placement of conventional dental implants. Moreover, bone loss around the scalloped implants was notably greater than that expected after traditional implant placement.

CONCLUSION

This chart review of 17 scalloped implants, followed for 18 months, determined that the scalloped implant design resulted in bone loss that was more severe than that associated with properly placed conventional dental implants. Further, the design showed no evidence of exceptional capacity to increase or maintain soft tissue height.