Scalloped Implant-Abutment Connection Compared to Conventional Flat Implant-Abutment Connection: a Systematic Review and Meta-Analysis

Influence of rough micro-threaded and laser micro-textured implant-neck on peri-implant tissues: A systematic review

Background and objective

This systematic review aimed to explore clinical outcomes of marginal or crestal bone level (MBL) and soft tissue status around implants, following the placement of rough micro-threaded/laser-microtextured surface (LMS) implants. These outcomes are compared with those following the placement of smooth machined-neck implants.

Materials and methods

Using EBSCO Information Services, we conducted a web-based search of databases such as the PubMed, Scopus, and EMBASE, for relevant English-language scientific papers published between January 2013 and August 2022. Prospective or retrospective controlled cohort studies and randomized controlled trials (RCTs) investigating the role of rough micro-threaded/LMS implant necks on MBL, sulcular probing depth (PD), and/or clinical attachment loss, were included in this review.

Results

From a comprehensive literature search of 247 articles, 6 RCTs, 5 prospective studies, and 4 retrospective studies (n = 15) fulfilled the eligibility criteria. MBL with rough micro-threaded implant necks ranged from 0.12 ± 0.17 mm to 3.25 ± 0.4 mm after loading. The smooth machined-neck implants without a micro-threaded neck had a loading MBL of 0.38 ± 0.51 mm to 3.75 ± 0.4 mm. Micro-threaded implant necks showed much lower MBL than machined-neck implants. LMS implant necks had a lower peri-implant PD than machined-neck implants after 3 years of early loading (2.3 ± 0.7 mm vs. 3.8 ± 0.8 mm). The experimental and control groups showed similar gingival recessions (1.08 ± 0.4 mm vs. 2.46 ± 0.3 mm). Meta-analysis was not feasible owing to heterogeneity of the studies.

Conclusion

Under functional loading, a roughened micro-threaded design for the implant neck could significantly lower MBL. Furthermore, PD and MBL were much lower around LMS neck implants than those around machined-neck or micro-threaded implants.

Can patients detect peri‑implant mucosal inflammation? Results from a multicentre randomized trial

PURPOSE

The objective of this study was to compare patient-reported outcomes (PROs) of peri‑implant soft tissue inflammation and aesthetics around single-tooth implants in the anterior maxillary region with three different implant-abutment interface designs.

METHODS

Participants were randomized to one of three different types of implant-abutment interface designs [Conical (CI), flat-to-flat (FI), and Platform Switched (PS)]. Implants and provisional crowns with prefabricated titanium abutments were placed 5 months following extraction and/or ridge augmentation. Permanent ceramic crowns with zirconia abutments were placed after 12 weeks. To assess PROs, appearance and inflammation questionnaires were completed from provisional crown placement to the 3-year follow-up.

RESULTS

Tooth appearance at the 3-year follow-up revealed a difference amongst CI, FI and PS implants (p=0.049; Kruskal-Wallis test). PS was rated better than FI (p=0.047) at 1 year for appearance of soft-tissue and satisfaction with colour. There were no differences for self-consciousness, smile and pain/discomfort while eating/hard food items.

CONCLUSIONS

Although participants tended to rate the health of mucosa around PS implants as slighty better than the other two implant systems, the differences were minimal and inconsistent. Thus, patient satisfaction in terms self-perceived gingival health and esthetics was high for all 3 systems tested, suggesting that patients are unable to detect mucosal inflammation.

CLINICAL SIGNIFICANCE

Patients find it difficult to perceive mucosal inflammation; hence, it is recommended that patients attend implant follow-up visits, even if they do not perceive inflammation. The study suggests that there is a relationship between the PROs and the clinical outcomes of tested implants.

Radiological Outcomes of Bone-Level and Tissue-Level Dental Implants: Systematic Review

Background: to assess the radiological marginal bone loss between bone-level or tissue-level dental implants through a systematic review of literature until September 2019. Methods: MEDLINE, Embase and other database were searched by two independent authors including only English articles. Results: The search provided 1028 records and, after removing the duplicates through titles and abstracts screening, 45 full-text articles were assessed for eligibility. For qualitative analysis 20 articles were included, 17 articles of them for quantitative analysis counting a total of 1161 patients (mean age 54.4 years) and 2933 implants, 1427 inserted at Tissue-level (TL) and 1506 inserted at Bone-level (BL). The survival rate and the success rate were more than 90%, except for 2 studies with a success rate of 88% and 86.2%. No studies reported any differences between groups in term of success and survival rates. Three studies showed that BL-implants had statistically less marginal bone loss (p < 0.05). Only one study reported statistically less marginal bone loss in TL-implants (p < 0.05). Conclusion: In the most part of the studies, differences between implant types in marginal bone loss were not statistically significant after a variable period of follow-up ranged between 1 and 5 years.

A 4 Year Human, Randomized, Radiographic Study of Scalloped versus Non-Scalloped Cemented Implants

Marginal bone loss (MBL) is a key factor in long-term implant success rate. Among the different factors that influence MBL, it is the different implant shoulder designs, such as scalloped or non-scalloped, which have been widely studied on screw retained but not on cemented retained implants. Thus, the aim of the present study was to evaluate the MBL around scalloped and non-scalloped cemented retained dental implants after 4 years of loading, in humans. A total of 15 patients were enrolled in the present study. A radiographic and clinical examination was performed after implant placement (T0) and after 4 years from it (T1). The results demonstrated a differential MBL (T1-T0) of 2.436 ± 1.103 mm and 1.923 ± 1.021 mm, respectively for test (scalloped) and control (non-scalloped) groups with a statistically significant difference between them. On the other hand, no statistically significant differences were found between the groups in terms of prosthetic complication and abutment decementation, whilst ceramic crowns chipping was shown in both groups. In conclusion, the use of a scalloped platform did not provide better results on the maintenance of MBL after 4 years follow-up. In this study, this probably was determined by multiple factors, among which was the subcrestal insertion of scalloped implants.