Effect of Platform Shift/Switch and Concave Abutments on Crestal Bone Levels and Mucosal Profile following Flap and Flapless Implant Surgery
Bibliographic record
Abstract
BACKGROUND: Crestal remodeling/bone loss appears to be a common sequel to dental implant placement. Several hypotheses/clinical strategies have been proposed to explain/avert crestal remodeling; however, causative mechanisms remain unclear and the efficacy of these clinical approaches uncertain. OBJECTIVE: The objective of the present study was to provide a histological account of crestal bone levels and mucosal profile at platform shift/switch and concave abutments following flapless and conventional flap surgery and subcrestal implant placement using a dog model. METHODS: Four dental implants each were placed in the left/right mandibular posterior jaw quadrants in five adult male Hound/Labrador mongrel dogs using flap surgery with a 1 × 5 mm gap defect or using a flapless approach, both involving placement 2 mm subcrestally and platform shift/switch versus concave abutments. Block biopsies for histological/histometric analysis were collected at 8 weeks. RESULTS: No significant differences were observed regarding crestal bone levels, with all groups showing mean bone levels above the implant platform. Similarly, crestal bone-implant contact was not significantly different among groups. Moreover, peri-implant mucosal profiles were not statistically different among groups for buccal sites; average mucosal height reached 4.1 to 4.9 mm above the implant platform. Comparison between buccal and lingual sites showed a nonsignificant tendency toward greater crestal resorption at buccal sites, adjusting for other factors. Mean crestal bone-implant contact level approximated the implant platform for lingual sites while consistently remaining below the platform at the buccal sites. Peri-implant mucosal height was significantly higher at buccal than at lingual sites, with the epithelial attachment located a significant distance away from the implant platform at buccal sites. CONCLUSIONS: The surgical approaches (subcrestal implant placement by flap surgery or a flapless approach) and abutment designs (platform shift/switch or concave) used in this study seem to have a limited impact on crestal remodeling, associated bone loss, and mucosal profile. Bioclinical strategies should be developed to circumvent the limitations of current clinical protocol.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".