The influence of the distance between narrow implants and the adjacent teeth on marginal bone levels

Analysis of risk factors related to early implant failure: A retrospective study

STATEMENT OF PROBLEM

Factors influencing early implant failure (failure during the healing period) in the rehabilitation and restoration of oral function in partially edentulous patients are unclear.

PURPOSE

The purpose of this clinical study was to investigate several factors that may be associated with early implant failure.

MATERIAL AND METHODS

This retrospective study was conducted on 3247 implants in 2061 patients between 2009 and 2022. Patient-related and surgery-related factors, including smoking; sex; diabetes; bone grafting; implant length, diameter, and design; adjacent teeth; and insertion torque, were manually retrieved and analyzed. Using univariate and multivariate analyses, a generalized estimating equation (GEE) model with chi-squared tests was employed to evaluate factors related to early implant failure (the failure before restoration) (α=.05).

RESULTS

The mean ±standard deviation age of the study patients was 49.2 ±15.0 years (range 18 to 91). Ninety-nine implants (3.05%) failed during the healing period. Three factors were statistically significant regarding early implant failure: smoking (odds ratio [OR]=1.92, P=.008), implant design (tapered implants) (OR=1.84, P=.007), and implant length <10 mm (OR=2.98, P=.011). Factors including diabetes, bone grafting, anatomic location, adjacent teeth (endodontic therapy in the adjacent teeth and the distance between implant and adjacent teeth), healing method, and insertion torque did not exhibit a statistically significant higher early implant failure rate. Ninety-three sites with failed implants received new implants, and 6 of these 93 implants failed during the healing period.

CONCLUSIONS

Within the limitation of sample size, smokers, implant length (<10 mm), and implant design (tapered implant) exhibited higher risk of early implant failure in this retrospective study. Implant insertion torque, healing method, adjacent teeth, and diabetes did not significantly influence the risk of early implant failure.

Suggested mesiodistal distance for multiple implant placement based on the natural tooth crown dimension with digital design

PURPOSE

The purpose of this investigation was to identify a mesiodistal algorithm for multiple posterior implant placement based upon an ideal prosthetically restoration design.

METHODS

One hundred one cases of posterior free-end edentulous arches were selected for digital crown designs and measurements. Cone bean computed tomogram and digital fabricated crown were applied. DICOM files were exported to a viewer software (BlueSkyPlan4) to generate digital crown and measurement. The mesiodistal space between roots of adjacent teeth and center of the potential implant horizontally, from both cross-section and coronal plane were measured. Comparisons were performed using t-tests.

RESULTS

No significant difference was found in the distances of the maxillary and mandibular posterior implants to adjacent natural teeth (p > 0.05). For interdental/implant distances, premolars are around 4.2 mm and molars are 5.4 mm, correspondently. The second premolar interimplant distance is around 7-7.4 mm. The distance of interimplant of the first molar is about 8-8.5 mm. For the maxillary second molar, the interimplant distance is 9.26 ± 0.29 mm and the mandibular second molar interimplant distance is 9.58 ± 0.19 mm, which is significantly different. No difference was found between the two different measurement methods.

CONCLUSION

A mesiodistal algorithm of 4-4.6 (implant to adjacent canine tooth), 7-7.4, 8-8.5, and 9-9.5 mm was recommended for interimplant/tooth distance from first premolar to second molar when placing implants with or without case-specific prosthetic planning prior to surgery.

Crestal bone changes around early vs. conventionally loaded implants with a multi-phosphonate coated surface: A randomized pilot clinical trial

OBJECTIVES

To compare the marginal bone level around implants with a thin multi-phosphonate coated surface after either an early or conventional loading protocol.

MATERIAL AND METHODS

A randomized pilot clinical trial was conducted. Dental impressions were obtained after either 4 (test) or 8 weeks (control) and single crowns screwed-in 2 weeks later. Several variables were evaluated including radiographical marginal bone level (MBL), patient's level variables, and those related to the restoration and surrounding tissues. These data were obtained at several time points up to a 1-year follow-up.

RESULTS

Thirty-four patients were included in the study, 18 assigned to the test group. No differences at implant placement were detected for tissue thickness, keratinized mucosa, nor any other clinical or radiological variable. At the time of impressions, tissue was thinner in the test group (2.30 (0.46) versus 2.78 (0.66) mm, test versus control, respectively; p = .012) so shorter abutments were used in this group. Regardless, no significant changes in marginal bone level were detected neither within group along time nor between groups. The average MBL at the 1-year follow-up was -0.15 (0.32) versus -0.22 (0.37) (p = .443) (test versus control, respectively). None of the clinical or radiological variables evaluated had a determinant influence on the MBL at any visit nor group.

CONCLUSION

The use of implants with a multi-phosphonate coated surface for early loading offers successful radiographical outcomes 1 year after loading. MBL over time was not affected by taking the impressions 4 or 8 weeks after implant placement and loading them 2 weeks later.

A 5-year longitudinal cohort study on crown to implant ratio effect on marginal bone level in single implants

BACKGROUND

A 5-year longitudinal cohort study was carried out to evaluate the influence of anatomical crown to implant ratio (CIR) on peri-implant marginal bone level (MBL) in single implants.

MATERIALS AND METHODS

The longest possible implants, according to the availability of pristine bone, were inserted, one per patient, among periodontally healthy teeth in consecutively recruited subjects. CIR and MBL changes were measured on standardized radiographs. The relationship between MBL and multiple predictors was investigated. A statistical analysis suitable for mixed type distributions was conducted: for the discrete component a logistic regression model was used and for the continuous component the impact of the variables on MBL was examined by using robust nonparametric comparison tests.

RESULTS

Seventy-eight dental implants were inserted in 34 mandibles and 44 maxillae, with one stage procedure in 40 cases and two stage in 38 cases. Thirty-five implants were <10 mm, while 43 were ≥ 10 mm long; 28 implants had a CIR ≤1 and 50 had a CIR >1. No drop-outs or implant loss were observed. Bone loss occurred only in a few cases, measuring less than 0.5 mm and being significantly more pronounced for implant length ≥10 mm, for lower CIR values and for the two stage procedure.

CONCLUSION

Higher CIR values were not related to increased peri-implant bone loss; a <10 mm long implant insertion may be safely considered for reduced bone heights.

Effect of incision design on interproximal bone loss of teeth adjacent to single implants. A randomized controlled clinical trial comparing intrasulcular vs paramarginal incision

PURPOSE

To evaluate the effect of incision design in implant surgery on interproximal bone loss of posterior teeth adjacent to interdental single implants, comparing intrasulcular and paramarginal incision. A further aim was to assess the influence of the incision technique on peri-implant bone remodeling.

MATERIALS AND METHODS

A controlled randomized clinical trial was carried out in a University Clinic. All the patients received an interdental posterior single implant. The incision type was randomly divided into two groups: (a) intrasulcular or (b) paramarginal. Standardized periapical digital radiographs were made with the parallel technique and a silicone index individualized in each patient. Radiographs were made immediately after implant placement, at abutment connection, 6 and 12 months post-loading. Two radiographic reference points were detected at the interproximal aspect of the adjacent teeth: (A) the cementoenamel junction and (B) the most coronal aspect of the bone crest. The interproximal bone loss of the adjacent teeth was calculated as the difference from A to B between the different follow-up periods and baseline. Two different examiners evaluated the radiographic measurements twice.

RESULTS

Sixty patients, each with one implant, were included, 30 in each group. A mean interproximal bone loss in teeth of 0.09 mm in the intrasulcular and 0.10 mm in the paramarginal group was found at 12 months post-loading. Mean peri-implant bone remodeling was 0.17 mm in the intrasulcular group and 0.15 mm in the paramarginal group. Differences between incision types were not statistically significant (p > .05).

CONCLUSIONS

Both incision designs used to place interdental single implants resulted in minimum bone loss at the interproximal aspect of adjacent teeth. The incision design did not significantly influence the radiographically assessed interproximal bone loss nor peri-implant bone remodeling.