Accuracy assessment of cone beam computed tomography-derived laboratory-based surgical templates on partially edentulous patients

Objectives: The aim of the present prospective clinical study was to evaluate the match between the positions and axes of the virtually planned and the placed implants using laboratory‐based surgical guides generated from cone beam computed tomography (CBCT). Materials and methods: A total of 132 implants were placed with the aid of 3D‐based transfer templates in 52 consecutive partially edentulous patients between April 2008 and March 2010. After individual adaptation of the scan templates and CBCT scanning, the acquired data for virtual implant planning and simulation were processed using the med3D software program. After finalizing the virtual placement of the implants the radiographic templates were converted into operative guides containing titanium sleeves for cavity preparation. Preoperative planning was merged with postoperative CBCT data to identify linear and angular deviations between virtually planned and placed implants. Results: Compared with the planned implants the installed implants showed linear deviations in the median at the neck and apex of 0.27 mm (range 0.01–0.97 mm), and of 0.46 mm (range 0.03–1.38 mm), respectively. The angle deviation was 1.84° in median, with a range of 0.07–6.26°. The extent of deviation depends on the size of the tooth gap and the distribution of the remaining teeth. Conclusion: The results of this study suggested that laboratory‐fabricated surgical guides using CBCT data may be reliable in implant placement under prosthodontic considerations in partial edentulism. To cite this article:
Behneke A, Burwinkel M, Knierim K, Behneke N. Accuracy assessment of cone beam computed tomography‐derived laboratory‐based surgical templates on partially edentulous patients.
Clin. Oral Impl. Res. 23 , 2012; 137–143.
doi: 10.1111/j.1600‐0501.2011.02176.x     

A prospective multicenter evaluation of immediately functionalized tapered conical connection implants for single restorations in maxillary anterior and premolar sites: 3-year results

Objectives

This multicenter prospective clinical trial investigated immediately provisionalized, anodized, conical connection, tapered implants with platform shifting in maxillary anterior and premolar sites.

Materials and methods

Patients requiring single-tooth implant-supported restorations in maxillary anterior and premolar sites were enrolled. Implants were immediately provisionalized and evaluated at insertion, 6 months, and annually thereafter. Outcome measures were marginal bone level change (ΔMBL), cumulative survival rate (CSR), and success rate, soft-tissue parameters, and oral health impact profile (OHIP). ΔMBL and Pink Esthetic Score were analyzed using Wilcoxon signed-rank tests. CSR was calculated using life table analysis. Other soft-tissue parameters were analyzed using sign tests.

Results

Of 94 enrolled patients (99 implants), 84 (88 implants) attended the 3-year follow-up. After an initial bone loss between implant insertion and 6 months (− 0.92 ± 1.23 mm), bone levels stabilized from 6 months to 3 years (0.13 ± 0.94 mm) with no significant change. The 3-year CSR was 98.9%, and the cumulative success rate was 96.9%. Papilla index scores of 2 or 3 were observed at 88.6% of sites at the 3-year visit compared with 32.8% at implant insertion. Improvements were observed for all other outcomes, including bleeding on probing, esthetics, plaque, and OHIP.

Conclusions

This restorative protocol was associated with high primary stability, patient satisfaction, stable bone levels, and an overall improvement of the soft tissue outcomes over a 3-year period.

Clinical relevance

The presented treatment is a viable option for single-tooth restorations of maxillary anterior teeth and premolars with successful short- to mid-long-term clinical outcomes.

     

Residual ridge resorption in the edentulous maxilla in patients with implant-supported mandibular overdentures: an 8-year retrospective study

PURPOSE: This retrospective study radiologically investigated alveolar bone resorption in the edentulous maxilla in patients with implant-supported mandibular overdentures. MATERIALS AND METHODS: This study consisted of 35 healthy, completely edentulous patients with a mean age of 59.7 years. They had received two implants between the mental foramina. New bar-retained mandibular overdentures and maxillary complete dentures were fabricated. Standardized panoramic radiographs taken subsequent to loading and at annual recall visits for up to 8 years were measured for alveolar bone loss in the maxilla. Bone areas and areas of reference not subject to resorption were measured with a planimetry program. The proportional value between both was expressed as a ratio (R). Bone loss was expressed as a change in R between two time points. Differences in the resorption rate between the anterior and posterior parts of the maxilla were investigated. RESULTS: Residual ridge resorption continued during the follow-up period and revealed high individual variability. With a range of 5% to 11% (median) loss in the original bone height, it was significantly (P < .031) more pronounced in the anterior than posterior maxilla (2% to 7%) from the second through eighth years. Regression analysis of the medians revealed a relatively high correlation between time and bone loss in both anterior and posterior parts of the maxilla. CONCLUSION: The anterior anchorage of mandibular overdentures by means of two implants and an ovoid bar was associated with slightly higher resorption in the anterior than in the posterior part of the edentulous maxilla.     

Long‐term evaluation of non‐submerged ITI implants. Part 1: 8‐year life table analysis of a prospective multi‐center study with 2359 implants.

In the present multi-center study. non-submerged ITI implants were prospectively followed to evaluate their long-term prognosis in fully and partially edentulous patients. In a total of 1003 patients, 2359 implants were consecutively inserted. Following a healing period of 3–6 months, the successfully integrated implants were restored with 393 removable and 758 fixed restorations. Subsequently, all consecutive implants were documented annually up to 8 years. At each examination, the clinical status of all implants was evaluated according to predefined criteria of success. Therefore, the data base allowed the evaluation of 8-year cumulative survival and success rates for 2359 implants. In addition, cumulative success rates were calculated for implant subgroups divided per implant type, implant length. and implant location. Furthermore, the actual 5-year survival and success rates could be determined for 488 implants. During the healing period, 13 implants did not successfully integrate, whereas 2346 implants fulfilled the predefined criteria of success. This corresponds with an early failure rate of 0.55%. During follow-up, 19 implants were classified as failures due to several reasons. In addition, 17 implants (= 0.8%) demonstrated at the last annual examination a suppurative periimplant infection. Including 127 drop out implants (= 5.4% drop out rate) into the calculation, the 8-year cumulative survival and success rates resulted in 96.7% and 93.3%, respectively. The analysis of implant subgroups showed slightly more favorable cumulative success rates for screw type implants (> 95%) compared to hollow-cylinder implants (91.3%). and clearly better success rates for mandibular implants (= 95%) when compared to maxillary implants (= 87%). The actual 5-year survival and success rates of 488 implants with 98.2% and 97.3%. respectively, were slightly better than the estimated 5-year cumulative survival and success rates of 2359 implants indicating that the applied life table analysis is a reliable statistical method to evaluate the long-term prognosis of dental implants. It can be concluded that non-submerged ITI implants maintain success rates well above 90% in different clinical centers for observation periods up to 8 years.     

A 5-year longitudinal study of the clinical effectiveness of ITI solid-screw implants in the treatment of mandibular edentulism

PURPOSE: The aim of this longitudinal study was to gain 5-year clinical documentation of the 1-stage surgical technique in connection with ITI solid-screw implants used in the edentulous mandible. MATERIALS AND METHODS: One hundred patients with totally edentulous mandibles were treated with bar-retained overdentures supported by a total of 340 consecutively placed ITI solid-screw implants. The patients were followed at annual intervals for at least 5 years to evaluate implant success, longitudinal reactions of the peri-implant hard and soft tissues, and incidences of biologic and mechanical complications. RESULTS: During the trial period, a total of 4 implants failed, all prior to loading, and 51 implants were lost to follow-up, resulting in a cumulative survival rate of 98.8% after 5 years of functional service. The success analysis included additional strictly defined events (either "first occurrence of marginal bone loss > or = 4 mm" or "first occurrence of pocket depth > or = 4 mm" and "first occurrence of crevicular fluid flow rate > or = 2.5 mm) and resulted in a cumulative 5-year success rate of 95.7%. The median marginal bone loss experienced between implant placement and prosthetic treatment was 0.5 mm, followed by an annual bone level change of 0.1 mm for the functional period of 5 years. The increasing incidence of remarkable plaque deposits from 19% to 50% represented the difficulties of the patients in maintaining a high level of oral hygiene, particularly for the lingual surfaces. Sulcus Bleeding Index, probing depth, attachment level, and crevicular fluid flow rate were used to describe the health of the peri-implant soft tissues and remained almost within acceptable standards. DISCUSSION: Survival and success rates of implants, amount of marginal bone loss, and periodontal indices of peri-implant soft tissues were consistent with those reported in the literature regarding implants with the submerged healing concept. CONCLUSION: With a cumulative survival rate of 98.8%, a cumulative success rate of 95.7%, and a median marginal bone loss of 0.5 mm during the healing period, followed by an annual rate of 0.1 mm after loading, non-submerged ITI solid-screw implants confirm the good clinical outcome of implant-supported treatment concepts for the rehabilitation of totally edentulous patients in a medium-term perspective.     

Randomized multicenter comparison of two coatings of intramobile cylinder implants in 313 partially edentulous mandibles followed up for 5 years

Intramobile cylinder (IMZ) implants with either of two coatings, hydroxyapatite (HA) or titanium plasma-flame (TPF), as distal abutments for combined tooth implant-supported restorations, were compared in 313 partially edentulous mandibles with respect to postprosthetical failure patterns and complication frequencies in a randomized multicenter clinical trial. Within the treatment protocols, the two coatings do not show evidence of different efficacy with respect to occurrence of postprosthetical integration deficiency (ID) or functional deficiency (FD). Statistical equivalence for an absolute effect of +/-15% in event-free survival could only be demonstrated for FD, not for ID, however. Intent-to-treat and per-protocol population analyses gave consistent results. Hazards of occurrence of ID and FD, adjusted for years of follow-up, were estimated for ID as 7% per year (95%CI 4-10% per year) with HA and 5% per year (95%CI 3-7% per year) with TPF, and for FD as 5% per year (95%CI 3-7% per year) with HA and 4% per year (95%CI 2-6% per year) with TPF. The 5-year cumulative success rates for no ID were 69.5% (95%CI 58-81%) with HA and 82.2% (95%CI 74-91%) with TPF. With respect to frequencies of complications, there was no relevant statistically significant difference between the two coatings.     

Immediately provisionalized tapered conical connection implants for single-tooth restorations in the maxillary esthetic zone: a 5-year prospective single-cohort multicenter analysis

Clinical Oral Investigations - This open, single-cohort, multicenter, prospective study investigated the efficacy of immediately provisionalized tapered conical connection implant for single-tooth...     

The longitudinal clinical effectiveness of ITI solid-screw implants in partially edentulous patients: a 5-year follow-up report

A total of 114 ITI solid-screw implants was consecutively placed in 55 partially edentulous patients and restored with 68 fixed prostheses. The patients were followed for at least 5 years in a prospective study that focused on implant success and longitudinal reactions of the peri-implant hard and soft tissues. During the study period, 5 implants failed and 15 implants were lost to follow-up, resulting in a cumulative survival rate of 95.3% after 5 years of loading. The success analysis included additional strictly defined events ("first occurrence of marginal bone loss > or = 4 mm," "first occurrence of pocket depth > or = 4 mm," and "first occurrence of crevicular fluid volume > or = 2.5 mm") and resulted in a cumulative 5-year success rate of 89.0%. Median loss of marginal bone, as observed on radiographs, was 0.7 mm between implant placement and prosthetic treatment and 0.5 mm between prosthesis placement and the 5-year evaluation. Compared to the previous year's value, the annual increase in marginal bone loss did not reach a level of statistical significance between 1 and 5 years of function, so that a steady state prevailed. The incidence of lingual-palatal surfaces affected with remarkable plaque deposits increased from 13% after prosthesis placement to 23% after 5 years. Sulcus Bleeding index, probing depth, attachment level, and crevicular fluid volume were used to describe the health of the peri-implant soft tissues. The research parameters remained almost unchanged and indicated a soft tissue response within physiologic levels. Most mechanical complications were experienced during the first year of loading and were related to loosening of occlusal screws, which occurred in 8 (12%) of 68 restorations.     

A new method for the radiological investigation of residual ridge resorption in the maxilla

OBJECTIVES: To develop a new method for assessing residual ridge resorption in the edentulous maxilla. METHODS: Defined experimental and reference areas in the maxilla were drawn on transparent film laid over a panoramic radiograph and digitized. Bone areas were measured with an integrated planimetry program and expressed as a ratio R. The effect of positioning errors on reliability of the method was investigated on dry skulls. The correlation between the change in ratio and actual bone loss was examined by progressively reducing the height of an artificial residual ridge on one skull. RESULTS: The coefficient of variation for the absolute ratio in different head positions was < 0.05 and its correlation coefficient of the change in R and the degree of resorption was r2 > or = 98.3%, P = 0.0001. CONCLUSIONS: Comparison of the experimental area with the reference area on serial panoramic radiographs appears suitable for the assessment of residual resorption in the maxilla.