Comparison of Clinical, Radiographic, and Immunologic Inflammatory Parameters around Crestally and Subcrestally Placed Dental Implants: 5-Year Retrospective Results

Influence of adjunctive non-surgical peri‑implant therapy on clinical and salivary cytokine profile in obese patients

AIM

The present study aimed to evaluate the impact of Photodynamic therapy (PDT) and Er,Cr:YSGG laser (ECL) adjunct to nonsurgical mechanical debridement (NSMD) in comparison to conventional NSMD in overweight individuals with peri‑implant disease on peri‑implant inflammatory parameters and cytokine levels of IL-6 and TNF-α in Peri-implant crevicular fluid (PICF) MATERIALS AND METHODS: Recruitment of volunteers was performed from the outpatient department according to predefined inclusion and exclusion criteria. Group 1 consisted of obese participants who underwent peri‑implant mechanical debridement (MD); group 2, obese participants who experienced MD adjunct to ECL, and in group 3, obese participants were treated with MD and adjunct PDT. Clinical periodontal parameters, plaque index (PI), bleeding index (BI) and probing depth (PD) along with crestal bone loss (CBL) were assessed at baseline, 3 months, and 6 months. PICF was collected to evaluate the levels of IL-6 and TNF-α. Kruskal-Wallis and Bonferroni post hoc test were employed for the comparison of peri‑implant inflammatory parameters and PICF cytokine profiles among the study groups.

RESULTS

Clinical peri‑implant parameters (PI, BI and PD) at baseline among subjects in group 1, group 2 and group 3 were comparable (p > 0.05). At 3 months follow up, mean scores of peri‑implant PI, BI, and PD (P <0.05) in group 1 (control) were significantly higher compared to group 2 (ECL) and 3 (PDT) (p < 0.05). At 6 months follow-up, PI and BI mean scores among groups 1, 2, and 3 were comparable (p>0.05). At 6 months participants in groups 2 and 3 noted significant difference (p<0.05) compared to baseline with no difference noted in the control group (p>0.05).

CONCLUSION

Photodynamic therapy and Er, Cr: YSGG adjunct to NSMD demonstrated significant improvement in peri‑implant inflammatory parameters in obese individuals. Multicentric clinical trials are suggested to extrapolate the findings of the present study.

The Long-Term Effect of Adapting the Vertical Position of Implants on Peri-Implant Health: A 5-Year Intra-Subject Comparison in the Edentulous Mandible Including Oral Health-Related Quality of Life

Despite high success rates of dental implants, surface exposure may occur as a consequence of biologic width establishment associated with surgery. This prospective split-mouth study evaluated the effect of early implant surface exposure caused by initial bone remodeling on long-term peri-implant bone stability and peri-implant health. Additionally, Oral Health-Related Quality of Life (OHRQoL) was assessed by means of the Oral Health Impact Profile-14 (OHIP-14). Twenty-six patients received two non-splinted implants supporting an overdenture in the mandible by means of locators. One implant was installed equicrestally (control) and the second one was installed subcrestally, taking at least 3 mm soft tissue thickness into account (test). During initial bone remodeling (up to 6 months postoperatively), equicrestal placement yielded 0.68 mm additional surface exposure compared to subcrestal placement (p < 0.001). Afterwards, bone level and peri-implant health were comparable in both treatment conditions and stable up to 5 years. The implant overdenture improved OHRQoL (p < 0.01) and remained unchanged thereafter (p = 0.51). In conclusion, adapting the vertical position of the implant concerning the soft tissue thickness prevents early implant surface exposure caused by initial bone remodeling, but in a well-maintained population, this has no impact on long-term prognosis. The treatment of edentulousness with an implant mandibular overdenture improves OHRQoL.

Bone Loss in Implants Placed at Subcrestal and Crestal Level: A Systematic Review and Meta-Analysis

Background: To assess differences in marginal bone loss in implants placed at subcrestal versus crestal level. Methods: An electronic and a manual research of articles written in English from Jaunary 2010 to January 2018 was performed by two independent reviewers. Clinical trials comparing bone loss for implants placed at crestal and subcrestal level were included. Pooled estimates from comparable studies were analyzed using a continuous random-effects model meta-analysis with the objective of assessing differences in crestal bone loss between the two vertical positions. Results: 16 studies were included; 10 studies did not encounter statistically significant differences between the two groups with respect to bone loss. Three articles found greater bone loss in subcrestal implants; while 3 found more bone loss in crestal implants. A meta-analysis for randomized control trial (RCT) studies reported an average and non-statistically different crestal bone loss of 0.028 mm. Conclusions: A high survival rate and a comparable bone loss was obtained both for crestal and subcrestal implants’ placement. Quantitative analysis considering a homogenous sample confirms that both vertical positions are equally valid in terms of perimplant bone loss. However, with respect to soft tissue; in presence of a thin tissue; a subcrestal placement of the implant should be preferred as it may reduce the probability for the implant to become exposed in the future and thus avoid the risk of suffering from peri-implant pathologies.

Impact of different placement depths on the crestal bone level of immediate versus delayed placed platform-switched implants

PURPOSE

The preservation of peri-implant bone is one requirement for long-term success of dental implants. The purpose of this study was to evaluate the impact of subcrestal placement on the crestal bone level of immediate versus delayed placed implants after loading.

MATERIALS AND METHODS

In this retrospective study, data of 159 patients who received 330 implants was analyzed. Implants were placed subcrestally, crestally or supracrestally into fresh sockets or healed sites. Vertical bone level height was assessed radiographically and implants were followed up annually. The influence of patient and implant related risk factors for peri-implant bone loss was evaluated using a linear mixed model.

RESULTS

Depth of implant placement was significantly correlated with peri-implant bone loss (P = 0.001, 95% CI). Least effective loss of crestal bone was determined when implants were placed between 1 mm and 1.99 mm subcrestally. Smoking significantly enhanced the risk of peri-implant bone loss (P = 0.04, 95% CI). Immediate implant placement was not positively correlated with peri-implant bone loss (P = 0.51, 95% CI).

CONCLUSION

Within the limits of this study, implant placement 1.08 mm subcrestally may be recommendable in order to avoid supracrestal expositions of platform-switched titanium implants over time.