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Mandibular Overdentures Retained by Mini Implants: a Clinical Trial Comparing Different Surgical and Loading Protocols (SMIS)

U

Universidade Federal de Goias

Status

Completed

Conditions

Edentulous Mouth
Complete Edentulism

Treatments

Procedure: Implant delayed loading
Procedure: Implant immediate loading
Procedure: Implant placement with flapless surgery
Procedure: Implant placement with flapped surgery

Study type

Interventional

Funder types

Other
Industry

Identifiers

NCT04760457
PI04011-2019

Details and patient eligibility

About

This study aims to test the combined effects of different loading protocols and surgical approaches on clinical and patient-reported outcome measures (PROMs) following the use of four mini implants for mandibular overdenture retention.

The main study hypotheses are:

  1. There are significant improvements in PROMs following implant intervention compared to baseline measures;
  2. Immediately loaded mini implants have similar failure rates compared to mini implants receiving a delayed 6-week protocol.
  3. Flapless surgery has similar post-insertion outcomes compared to flapped surgery.

Full description

This study aims to test the combined effects of different loading protocols and surgical approaches on clinical and patient-reported outcome measures (PROMs) following the use of four mini implants for mandibular overdenture retention.

Main study hypotheses:

  1. There are significant improvements in PROMs following implant intervention compared to baseline measures;
  2. Immediately loaded mini implants have similar failure rates compared to mini implants receiving a delayed 6-week protocol;
  3. Flapless surgery has similar post-insertion outcomes compared to flapped surgery.

Statement of clinical relevance:

Mini implants are an alternative to standard implants for overdentures. They are suitable for insertion in narrow ridges, are less invasive, simpler, less costly, and faster to perform, and are especially advantageous for older and frail patients who would benefit from more conservative and less burdensome treatments. Although previous studies reported favorable outcomes regarding patient oral comfort and function, there is a need for implant/attachment systems with higher predictability on implant survival and retention performance in the long-term. This study aims to provide clinical evidence on the newly developed 2.4mm one-piece TiZr mini implant with a miniaturized carbon-based coating attachment.

Methods:

This is a randomized clinical trial using a factorial design, to test the effectiveness of a mandibular overdenture retained by four mini implants. Participants will be randomized using a 2×2 factorial design: immediate/delayed loading (factor 1) and flapless/flapped surgery (factor 2). New conventional complete dentures will be provided as the baseline treatment. Next, eligible participants will be those who completed a 6-month period of denture usage, and are in need of implants to improve the function of the mandibular denture. Imaging exam should present a minimum of 5.4 mm of ridge width in the interforaminal region (recommended for flapless surgery).

Included subjects to take part in the RCT will be randomized to the treatment groups according to the combined study factors - loading protocols: immediate (IL) or delayed (DL); and surgical approaches: flapless (FLS) or flapped (FPS) surgery. Hence, the combined factors will results in four groups:

  • IL/FLS (Group I)
  • IL/FPS (Group II)
  • DL/FLS (Group III)
  • DL/FPS (Group IV) Considering the patient's perspective this study design assumed a "worst" protocol (delayed and flapped - Group IV) and a "best" protocol (flapless and immediate - Group I) and two other intermediary conditions (flapped/immediate and flapless/delayed).

All participants will receive four Straumann® Mini Implant System (one-piece Tissue Level implants) with an Optiloc® prosthetic connection and PEEK matrix inserts. Surgery will follow the workflow for the surgical procedure for the Straumann® Mini Implant System concerning preoperative planning, implant bed preparation and implant insertion. For the prosthetic procedures, we will perform a chairside incorporation of the retentive inserts to convert the existing well-fitting and well-functioning lower denture into an overdenture with the Optiloc® Retentive System/Straumann® Mini Implants.

Outcomes will include short-term outcomes (Patient perceived burdens in surgery, postoperative swelling and pain, consumption of analgesics and surgical time) and long-term - 1-year (implant survival and success, peri-implant marginal bone level changes, PROMs, retention force, prosthodontic events) outcomes. Sample size calculation resulted in a total of 74 participants, 18 in each of the four groups. Data analysis will include descriptive and bivariate analyses, Kaplan-Meier curves and regression models using Generalized Estimating Equations (GEE) for longitudinal data.

Enrollment

74 patients

Sex

All

Volunteers

No Healthy Volunteers

Inclusion criteria

  • No contraindications for implant surgery (mainly related to uncontrolled systemic diseases);
  • Enough bone height in the interforaminal area for an implant length of at least 10 mm;
  • Ability to understand and answer the questionnaires used in the study and agree to participate by providing a written informed consent.

Exclusion criteria

  • Noncompliant participants;
  • Disagreement to be randomly allocated to the treatment study groups;
  • Signs of untreated temporomandibular disorders or uncontrolled systemic or oral conditions that require additional treatments.

Trial design

Primary purpose

Treatment

Allocation

Randomized

Interventional model

Factorial Assignment

Masking

Single Blind

74 participants in 4 patient groups

IL-FLS
Active Comparator group
Description:
Immediate loading (IL) and Flapless surgery (FLS)
Treatment:
Procedure: Implant immediate loading
Procedure: Implant placement with flapless surgery
IL-FPS
Active Comparator group
Description:
Immediate loading (IL) and Flapped surgery (FPS)
Treatment:
Procedure: Implant immediate loading
Procedure: Implant placement with flapped surgery
DL-FLS
Active Comparator group
Description:
Delayed loading (DL) and Flapless surgery (FLS)
Treatment:
Procedure: Implant delayed loading
Procedure: Implant placement with flapless surgery
DL-FPS
Active Comparator group
Description:
Delayed loading (DL) and Flapped surgery (FPS)
Treatment:
Procedure: Implant delayed loading
Procedure: Implant placement with flapped surgery

Trial contacts and locations

1

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Data sourced from clinicaltrials.gov

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