Clinical trial NCT04760457: Mandibular Overdentures Retained by Mini Implants: a Clinical Trial Comparing Different Surgical and Loading Protocols
Official title: One-piece TiZr Mini Implants With Miniaturized Carbon-based Coating Prosthetic Connection for Mandibular Overdentures: a Factorial, Randomized Clinical Trial Testing the Outcomes of Immediate/Delayed Loading and Flapped/Flapless Surgery
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Edentulous Mouth
Complete Edentulism
Keywords: Overdenture
Mini implant
Flapless surgery
Dental implant
Implant loading protocol
Lead sponsor: Universidade Federal de Goias
Sponsor class: OTHER
Collaborators: name: ITI International Team for Implantology, Switzerland
name: Institut Straumann AG
First posted: 2021-02-18
Enrollment: 74
Sex: ALL
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: FACTORIAL
Intervention model description: A factorial experiment of two factors is planned, each with two possible values or "levels", and whose experimental units take on all possible combinations of these levels across all such factors (2×2 factorial design), allowing the study to determine the effect of each factor on the response variable, as well as the effects of interactions between factors on the response variable. The tested factors will be: loading protocol (immediate or delayed), and surgical approach (flapped or flapless), resulting in a factorial experiment with four treatment combinations in total. Hence, the design is denoted a 2² factorial, which identifies the number of factors (n=2) and how many levels each factor has (n=2) there are in the design (2²=4).
Primary purpose: TREATMENT

Brief summary: 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.

Detailed 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.

Eligibility criteria: 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.

Primary outcomes:
measure: Patient-perceived burdens
timeFrame: Twenty-four hours after implant surgery.
measure: Implant survival and success
timeFrame: Incidence thoughout the 12-month follow-up after implant placement.
measure: Postoperative pain and discomfort
timeFrame: Assessed 24 hours after implant placement.
measure: Postoperative pain and discomfort
timeFrame: Assessed 72 hours after implant placement.
measure: Postoperative pain and discomfort
timeFrame: Assessed 1 week after implant placement.
measure: Consumption of analgesics
timeFrame: Assessed until 1 week after implant placement.
measure: Patient Satisfaction
timeFrame: Assessed at baseline (before implant surgery)
measure: Patient Satisfaction
timeFrame: Assessed at the 3-month follow-up visit after implant placement.
measure: Patient Satisfaction
timeFrame: Assessed at the 6-month follow-up visit after implant placement.
measure: Patient Satisfaction
timeFrame: Assessed at the 12-month follow-up visit after implant placement.
measure: Oral health-related quality of life (OHRQoL)
timeFrame: Assessed at baseline (before implant surgery).
measure: Oral health-related quality of life (OHRQoL)
timeFrame: Assessed at the 3-month follow-up visit after implant placement.
measure: Oral health-related quality of life (OHRQoL)
timeFrame: Assessed at the 6-month follow-up visit after implant placement.
measure: Oral health-related quality of life (OHRQoL)
timeFrame: Assessed at the 12-month follow-up visit after implant placement.
measure: Prosthodontic maintenance events
timeFrame: Throughout 12 months after overdenture delivery.
measure: Surgical time
timeFrame: Procedure (Assessed during the clinical visit of implant placement and overdenture delivery or denture adaptation.)
Secondary outcomes:
measure: Masticatory Performance
timeFrame: Assessed at baseline (before implant surgery).
measure: Masticatory Performance
timeFrame: Assessed at the 3-month follow-up visit after implant placement.
measure: Masticatory Performance
timeFrame: Assessed at the 6-month follow-up visit after implant placement.
measure: Masticatory Performance
timeFrame: Assessed at the 12-month follow-up visit after implant placement.
measure: Maximum voluntary bite force
timeFrame: Assessed at baseline (before implant surgery).
measure: Maximum voluntary bite force
timeFrame: Assessed at the 3-month follow-up visit after implant placement.
measure: Maximum voluntary bite force
timeFrame: Assessed at the 6-month follow-up visit after implant placement.
measure: Maximum voluntary bite force
timeFrame: Assessed at the 12-month follow-up visit after implant placement.
measure: Peri-implant bone change
timeFrame: Peri-implant bone loss at the 3-month follow-up compared to initial stage (1-week rediograph).
measure: Peri-implant bone change
timeFrame: Peri-implant bone loss at the 6-month follow-up compared to initial stage (1-week rediograph).
measure: Peri-implant bone change
timeFrame: Peri-implant bone loss at the 12-month follow-up compared to initial stage (1-week rediograph).
measure: Bleeding on probing
timeFrame: Assessed at 6-month post-insertion
measure: Bleeding on probing
timeFrame: Assessed at 12-month post-insertion
measure: Probing depth
timeFrame: Assessed at 6-month post-insertion
measure: Probing depth
timeFrame: Assessed at 12-month post-insertion
measure: Suppuration
timeFrame: Assessed at 6-month post-insertion
measure: Suppuration
timeFrame: Assessed at 12-month post-insertion
Other outcomes:
Locations:
city: Goiânia
country: Brazil
facility: School of Dentistry, Federal University of Goias
state: Goias
Study officials:
affiliation: Universidade Federal de Goias
name: Claudio R Leles, DDS, PhD
role: STUDY_DIRECTOR
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