Mandibular Overdentures Retained by Mini Implants: a Clinical Trial Comparing Different Surgical and Loading Protocols
NCT ID: NCT04760457
Last Updated: 2023-05-10
Study Results
Results pending
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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Recruitment Status
COMPLETED
Clinical Phase
NA
Total Enrollment
74 participants
Study Classification
INTERVENTIONAL
Study Start Date
2021-03-01
Study Completion Date
2022-11-30
Brief Summary
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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.
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.
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Detailed Description
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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.
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.
Conditions
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Edentulous Mouth
Complete Edentulism
Study Design
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Allocation Method
RANDOMIZED
Intervention Model
FACTORIAL
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 Study Purpose
TREATMENT
Blinding Strategy
SINGLE
Outcome Assessors
The assessment of longitudinal outcomes will be performed by an assessor blinded to the surgical/loading protocols
Study Groups
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IL-FLS
Immediate loading (IL) and Flapless surgery (FLS)
Group Type
ACTIVE_COMPARATOR
Implant placement with flapless surgery
Intervention Type
PROCEDURE
Four mini implants will be placed without reflecting a flap.
Implant immediate loading
Intervention Type
PROCEDURE
Four mini implants will be immediately loaded.
IL-FPS
Immediate loading (IL) and Flapped surgery (FPS)
Group Type
ACTIVE_COMPARATOR
Implant placement with flapped surgery
Intervention Type
PROCEDURE
Four mini implants will be placed reflecting a flap.
Implant immediate loading
Intervention Type
PROCEDURE
Four mini implants will be immediately loaded.
DL-FLS
Delayed loading (DL) and Flapless surgery (FLS)
Group Type
ACTIVE_COMPARATOR
Implant placement with flapless surgery
Intervention Type
PROCEDURE
Four mini implants will be placed without reflecting a flap.
Implant delayed loading
Intervention Type
PROCEDURE
Four mini implants will be loaded after a 6-week healing period.
DL-FPS
Delayed loading (DL) and Flapped surgery (FPS)
Group Type
ACTIVE_COMPARATOR
Implant placement with flapped surgery
Intervention Type
PROCEDURE
Four mini implants will be placed reflecting a flap.
Implant delayed loading
Intervention Type
PROCEDURE
Four mini implants will be loaded after a 6-week healing period.
Interventions
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Implant placement with flapped surgery
Four mini implants will be placed reflecting a flap.
Intervention Type
PROCEDURE
Implant placement with flapless surgery
Four mini implants will be placed without reflecting a flap.
Intervention Type
PROCEDURE
Implant immediate loading
Four mini implants will be immediately loaded.
Intervention Type
PROCEDURE
Implant delayed loading
Four mini implants will be loaded after a 6-week healing period.
Intervention Type
PROCEDURE
Eligibility Criteria
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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.
* 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.
* 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.
Eligible Sex
ALL
Accepts Healthy Volunteers
No
Sponsors
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ITI International Team for Implantology, Switzerland
OTHER
Sponsor Role
collaborator
Institut Straumann AG
INDUSTRY
Sponsor Role
collaborator
Universidade Federal de Goias
OTHER
Sponsor Role
lead
Responsible Party
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Cláudio Rodrigues Leles
Full Professor
Responsibility Role
PRINCIPAL_INVESTIGATOR
Principal Investigators
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Claudio R Leles, DDS, PhD
Role: STUDY_DIRECTOR
Universidade Federal de Goias
Locations
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School of Dentistry, Federal University of Goias
Goiânia, Goiás, Brazil
Site Status
Countries
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Brazil
References
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Awad MA, Feine JS. Measuring patient satisfaction with mandibular prostheses. Community Dent Oral Epidemiol. 1998 Dec;26(6):400-5. doi: 10.1111/j.1600-0528.1998.tb01978.x.
Reference Type
BACKGROUND
de Grandmont P, Feine JS, Tache R, Boudrias P, Donohue WB, Tanguay R, Lund JP. Within-subject comparisons of implant-supported mandibular prostheses: psychometric evaluation. J Dent Res. 1994 May;73(5):1096-104. doi: 10.1177/00220345940730051201.
Reference Type
BACKGROUND
Demain S, Goncalves AC, Areia C, Oliveira R, Marcos AJ, Marques A, Parmar R, Hunt K. Living with, managing and minimising treatment burden in long term conditions: a systematic review of qualitative research. PLoS One. 2015 May 29;10(5):e0125457. doi: 10.1371/journal.pone.0125457. eCollection 2015.
Reference Type
BACKGROUND
Enkling N, Saftig M, Worni A, Mericske-Stern R, Schimmel M. Chewing efficiency, bite force and oral health-related quality of life with narrow diameter implants - a prospective clinical study: results after one year. Clin Oral Implants Res. 2017 Apr;28(4):476-482. doi: 10.1111/clr.12822. Epub 2016 Mar 24.
Reference Type
BACKGROUND
Enkling N, Haueter M, Worni A, Muller F, Leles CR, Schimmel M. A prospective cohort study on survival and success of one-piece mini-implants with associated changes in oral function: Five-year outcomes. Clin Oral Implants Res. 2019 Jun;30(6):570-577. doi: 10.1111/clr.13444. Epub 2019 May 8.
Reference Type
BACKGROUND
Kanazawa M, Feine J, Esfandiari S. Clinical guidelines and procedures for provision of mandibular overdentures on 4 mini-dental implants. J Prosthet Dent. 2017 Jan;117(1):22-27. doi: 10.1016/j.prosdent.2016.04.020. Epub 2016 Aug 1.
Reference Type
BACKGROUND
Klein MO, Schiegnitz E, Al-Nawas B. Systematic review on success of narrow-diameter dental implants. Int J Oral Maxillofac Implants. 2014;29 Suppl:43-54. doi: 10.11607/jomi.2014suppl.g1.3.
Reference Type
BACKGROUND
Leao A, Sheiham A. Relation between clinical dental status and subjective impacts on daily living. J Dent Res. 1995 Jul;74(7):1408-13. doi: 10.1177/00220345950740071301.
Reference Type
BACKGROUND
Leao A, Sheiham A. The development of a socio-dental measure of dental impacts on daily living. Community Dent Health. 1996 Mar;13(1):22-6.
Reference Type
BACKGROUND
Lemos CA, Verri FR, Batista VE, Junior JF, Mello CC, Pellizzer EP. Complete overdentures retained by mini implants: A systematic review. J Dent. 2017 Feb;57:4-13. doi: 10.1016/j.jdent.2016.11.009. Epub 2016 Nov 22.
Reference Type
BACKGROUND
Marcello-Machado RM, Faot F, Schuster AJ, Nascimento GG, Del Bel Cury AA. Mini-implants and narrow diameter implants as mandibular overdenture retainers: A systematic review and meta-analysis of clinical and radiographic outcomes. J Oral Rehabil. 2018 Feb;45(2):161-183. doi: 10.1111/joor.12585. Epub 2017 Dec 2.
Reference Type
BACKGROUND
Reissmann DR, Semmusch J, Farhan D, Smeets R, Heiland M, Heydecke G. Development and validation of the Burdens in Oral Surgery Questionnaire (BiOS-Q). J Oral Rehabil. 2013 Oct;40(10):780-7. doi: 10.1111/joor.12092. Epub 2013 Aug 27.
Reference Type
BACKGROUND
Reissmann DR, Enkling N, Moazzin R, Haueter M, Worni A, Schimmel M. Long-term changes in oral health-related quality of life over a period of 5 years in patients treated with narrow diameter implants: A prospective clinical study. J Dent. 2018 Aug;75:84-90. doi: 10.1016/j.jdent.2018.05.019. Epub 2018 May 28.
Reference Type
BACKGROUND
Schiegnitz E, Al-Nawas B. Narrow-diameter implants: A systematic review and meta-analysis. Clin Oral Implants Res. 2018 Oct;29 Suppl 16:21-40. doi: 10.1111/clr.13272.
Reference Type
BACKGROUND
Souza RF, Patrocinio L, Pero AC, Marra J, Compagnoni MA. Reliability and validation of a Brazilian version of the Oral Health Impact Profile for assessing edentulous subjects. J Oral Rehabil. 2007 Nov;34(11):821-6. doi: 10.1111/j.1365-2842.2007.01749.x.
Reference Type
BACKGROUND
Misch CE, Perel ML, Wang HL, Sammartino G, Galindo-Moreno P, Trisi P, Steigmann M, Rebaudi A, Palti A, Pikos MA, Schwartz-Arad D, Choukroun J, Gutierrez-Perez JL, Marenzi G, Valavanis DK. Implant success, survival, and failure: the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference. Implant Dent. 2008 Mar;17(1):5-15. doi: 10.1097/ID.0b013e3181676059.
Reference Type
BACKGROUND
Ferreira de Sa J, Nascimento LN, de Moraes Sousa JF, Curado TFF, Srinivasan M, McKenna G, Schimmel M, Leles CR. The Effect of Implant Distribution on Functional and Patient-Reported Outcomes of Mandibular Overdentures Retained by Four Mini Implants. J Oral Rehabil. 2025 Sep;52(9):1452-1460. doi: 10.1111/joor.14024. Epub 2025 May 9.
Reference Type
DERIVED
Curado TFF, Nascimento LN, Silva JR, de Paula MS, Schimmel M, McKenna G, Leles CR. Mandibular overdenture retained by four one-piece titanium-zirconium mini implants: A 2-year RCT on patient-reported outcomes. J Dent. 2024 Oct;149:105267. doi: 10.1016/j.jdent.2024.105267. Epub 2024 Jul 26.
Reference Type
DERIVED
Leles CR, Curado TFF, Nascimento LN, Silva JR, de Paula MS, McKenna G, Schimmel M. Changes in masticatory performance and bite force after treatment with mandibular overdentures retained by four titanium-zirconium mini implants: One-year randomised clinical trial. J Oral Rehabil. 2024 Aug;51(8):1459-1467. doi: 10.1111/joor.13722. Epub 2024 Apr 29.
Reference Type
DERIVED
Other Identifiers
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PI04011-2019
Identifier Type: -
Identifier Source: org_study_id
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