Narrow-diameter implants with conical connection for restoring the posterior edentulous region

Clinical evaluation of 3.0-mm narrow-diameter implants: a retrospective study with up to 5 years of observation

PURPOSE

This study aimed to evaluate the clinical outcomes of a single type of narrow-diameter implant (NDI) by investigating its survival rate and peri-implant marginal bone loss (MBL). In addition, variables possibly related to implant survival and MBL were investigated to identify potential risk factors.

METHODS

The study was conducted as a retrospective study involving 49 patients who had received 3.0-mm diameter TSIII implants (Osstem Implant Co.) at Seoul National University Dental Hospital. In total, 64 implants were included, and dental records and radiographic data were collected from 2017 to 2022. Kaplan-Meier survival curves and a Cox proportional hazard model were used to estimate the implant survival rate and to investigate the effects of age, sex, jaw, implant location, implant length, the stage of surgery, guided bone regeneration, type of implant placement, and the surgeon's proficiency (resident or professor) on implant survival. The MBL of the NDIs was measured, and the factors influencing MBL were evaluated.

RESULTS

The mean observation period was 30.5 months (interquartile range, 26.75-45 months), and 6 out of 64 implants failed. The survival rate of the NDIs was 90.6%, and the multivariate Cox regression analysis showed that age was associated with implant failure (hazard ratio, 1.17; 95% confidence interval, 1.04-1.31, P=0.01). The mean MBL was 0.44±0.75 mm, and no factors showed statistically significant associations with greater MBL.

CONCLUSIONS

NDIs can be considered a primary alternative when standard-diameter implants are unsuitable. However, further studies are required to confirm their long-term stability.

Use of narrow-diameter implants in the posterior segments of the jaws: A retrospective observational study of 2 to 11 years

STATEMENT OF PROBLEM

The placement of narrow-diameter implants (NDIs) in the posterior region is still debated in view of the high biomechanical risks in these areas.

PURPOSE

The purpose of this retrospective observational study was to evaluate the success and survival rates of NDIs restored with fixed prostheses in the posterior region (primary outcome) and analyze whether splinting multiple units (prosthesis design) affects the biological and mechanical complications (secondary outcome).

MATERIAL AND METHODS

Dental records from 2 private clinics were reviewed for NDIs in the posterior region installed between 2009 and 2018. Ninety study participants (58 women and 32 men) aged between 21 and 84 years (mean age 49.9 years) were recalled for the assessment of implant survival and success of 160 NDIs previously provided for partial posterior edentulism associated with moderate horizontal bone loss or reduced interradicular space (105 premolars and 55 molars). The implants were restored with metal-ceramic single crowns or splinted multiple-unit prostheses, either screw-retained or cemented on custom (n=100) or stock titanium abutments (n=60). Peri-implant probing depth (PPD), bleeding on probing (BOP), bone quality, type of edentulism, and patient satisfaction were scored. The chi-squared test for independence and 2-sample Welch t test were performed for statistical analysis (α=.05).

RESULTS

The overall success rate was 89.37%. One implant had been removed 4 years after loading, another after 9 years, yielding a cumulative survival rate of 98.75%. Fourteen implants exhibited PPD > 5 mm. One implant and 1 abutment screw fractured, and 16 restorations demonstrated porcelain chipping. The chi-squared test showed no significant relationship between prosthetic design and complications whether biological (P=.087) or mechanical (P=.805). Eighty-two percent of patients were satisfied with esthetics, 76% with function, 85% with total duration of treatment, and 90% with overall treatment cost.

CONCLUSIONS

Within the limitations of this retrospective study, NDIs may be considered a reliable option to replace posterior teeth. The prosthetic design had no significant impact on biological or mechanical complications.

Treatment of dental implant displacement into the maxillary sinus

Background

Displacement of dental implants into the maxillary sinus is rare, but it primarily occurs in patients with severe pneumatization of the maxillary sinus and/or deficiency of the alveolar process. Some complications such as the infection of the paranasal sinuses and formation of the oroantral fistula can be followed by the displacement of a dental implant. Therefore, the displaced implant has to be removed immediately with surgical intervention show and another plan for rehabilitation should be considered.

Main body

The conventional procedure for the removal of a displaced implant from the maxillary sinus involves sinus bone grafting and new implant placement performed in two or more steps with a significant time gap in between. Simplification of these surgical procedures can decrease the treatment duration and patient discomfort.

Conclusions

In this review, we discuss the anatomical characteristics of the maxillary sinus and the complications associated with implant displacement into the sinus.

The rate and stability of mandibular block bone graft in recent 5 years

Background

The purposes of the present study were to compare implant stabilities of mandibular block bone graft and bovine bone graft and to evaluate influencing factors for implant stability in mandibular block bone (MBB) graft.

Methods

This retrospective study investigated 1224 cases and 389 patients treated by one surgeon in the Department of Oral and Maxillofacial Surgery of Pusan National University Dental Hospital (Yangsan, Korea) between January 2010 and December 2014. Proportions that MBB graft cases constitute in all implant restoration cases and in all bone graft cases were measured. Implant stability quotient (ISQ) values were achieved by the same surgeon before loading. The average ISQ values of the experimental groups were compared. In addition, ISQ values of influencing factors, such as age, sex, implant size, and implant placement site, were compared within the MBB group using Osstell^TM Mentor (Osstell®, Göteborg, Sweden). Paired t test and ANOVA were conducted for statistical analysis with a significance level of 0.05.

Results

Fifty-five percent of all implant restoration cases performed bone graft while MBB cases constituted 34% of all implant restoration cases and 61% of all bone graft cases. Comparing ISQ values according to bone graft materials, the MBB group manifested sufficient implant stability by presenting comparable ISQ value to that of the experimental group without bone graft. Among the reviewed factors, females, mandibular molar regions, and implants in larger diameter displayed greater implant stabilities.

Conclusions

Satisfactory implant stability was accomplished upon administration of MBB graft. Within the limitation of this study, gender, implant site, and implant diameter were speculated to influence on implant stability in MBB graft.