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Completed

NCT Number: NCT04760457

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

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.

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Key information

Conditions

Edentulous Mouth Complete Edentulism Mouth Diseases Mouth, Edentulous Stomatognathic Diseases Tooth Diseases

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

School of Dentistry, Federal University of Goias

Goiânia, Goiás, 74605-220, Brazil

About this study

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:

  • There are significant improvements in PROMs following implant intervention compared to baseline measures;
  • Immediately loaded mini implants have similar failure rates compared to mini implants receiving a delayed 6-week protocol;
  • 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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Implant placement with flapped surgery

Procedure

Four mini implants will be placed reflecting a flap.

Implant placement with flapless surgery

Procedure

Four mini implants will be placed without reflecting a flap.

Implant immediate loading

Procedure

Four mini implants will be immediately loaded.

Implant delayed loading

Procedure

Four mini implants will be loaded after a 6-week healing period.

Primary outcomes

  1. Patient-perceived burdens

    Time frame: Twenty-four hours after implant surgery.

    The Burdens in Oral Surgery Questionnaire (BiOS-Q) will be used to assess patient-perceived burdens. It includes 16 items concerning all aspects of procedures occurring during a surgery. Responses for each item are assessed using a visual analogue scale (VAS) ranging from 0 = no expression of the attribute (e.g. not unpleasant at all) to 100 = maximum expression (e.g. very unpleasant).

  2. Implant survival and success

    Time frame: Incidence thoughout the 12-month follow-up after implant placement.

    Each implant will be assessed according to the health scale of the International Congress of Oral Implantologists (ICOI-Pisa health scale). After clinical assessment, each implant will be classified as 'success', 'satisfactory survival', 'compromised survival' or 'failure'.

  3. Postoperative pain and discomfort

    Time frame: Assessed 24 hours after implant placement.

    A 100-cm graduated visual analog scale will be used to evaluate participants' assessments of pain and discomfort regarding the surgical process. Each participant will indicate their level of pain and discomfort with each parameter by marking a point along the scale.

  4. Postoperative pain and discomfort

    Time frame: Assessed 72 hours after implant placement.

    A 100-cm graduated visual analog scale will be used to evaluate participants' assessments of pain and discomfort regarding the surgical process. Each participant will indicate their level of pain and discomfort with each parameter by marking a point along the scale.

  5. Postoperative pain and discomfort

    Time frame: Assessed 1 week after implant placement.

    A 100-cm graduated visual analog scale will be used to evaluate participants' assessments of pain and discomfort regarding the surgical process. Each participant will indicate their level of pain and discomfort with each parameter by marking a point along the scale.

  6. Consumption of analgesics

    Time frame: Assessed until 1 week after implant placement.

    The number of analgesics consumed by the participant during the post-operative and healing period will be recorded in the patient's file.

  7. Patient Satisfaction

    Time frame: Assessed at baseline (before implant surgery)

    The McGill Denture Satisfaction Instrument - DSI (Awad & Feine, 1998; de Grandmont et al., 1994) will be used to assess patients' satisfaction relating to their prostheses. This is a treatment-specific patient-based outcome assessing satisfaction relating to several aspects of the mandibular prosthesis, including general satisfaction, comfort, stability, aesthetics, chewing ability (ease of chewing), chewing efficiency (ability to crush food in small particles), ease of cleaning, ability to speak and oral condition (condition of their mouth, which can refer to oral health status and was measured by "In general, are you satisfied with your oral condition?''. The subjects will answer on a 100 mm visual analogue scale (VAS) anchored by the words 'not at all satisfied' and 'extremely satisfied'.

  8. Patient Satisfaction

    Time frame: Assessed at the 3-month follow-up visit after implant placement.

    The McGill Denture Satisfaction Instrument - DSI (Awad & Feine, 1998; de Grandmont et al., 1994) will be used to assess patients' satisfaction relating to their prostheses. This is a treatment-specific patient-based outcome assessing satisfaction relating to several aspects of the mandibular prosthesis, including general satisfaction, comfort, stability, aesthetics, chewing ability (ease of chewing), chewing efficiency (ability to crush food in small particles), ease of cleaning, ability to speak and oral condition (condition of their mouth, which can refer to oral health status and was measured by "In general, are you satisfied with your oral condition?''. The subjects will answer on a 100 mm visual analogue scale (VAS) anchored by the words 'not at all satisfied' and 'extremely satisfied'.

  9. Patient Satisfaction

    Time frame: Assessed at the 6-month follow-up visit after implant placement.

    The McGill Denture Satisfaction Instrument - DSI (Awad & Feine, 1998; de Grandmont et al., 1994) will be used to assess patients' satisfaction relating to their prostheses. This is a treatment-specific patient-based outcome assessing satisfaction relating to several aspects of the mandibular prosthesis, including general satisfaction, comfort, stability, aesthetics, chewing ability (ease of chewing), chewing efficiency (ability to crush food in small particles), ease of cleaning, ability to speak and oral condition (condition of their mouth, which can refer to oral health status and was measured by "In general, are you satisfied with your oral condition?''. The subjects will answer on a 100 mm visual analogue scale (VAS) anchored by the words 'not at all satisfied' and 'extremely satisfied'.

  10. Patient Satisfaction

    Time frame: Assessed at the 12-month follow-up visit after implant placement.

    The McGill Denture Satisfaction Instrument - DSI (Awad & Feine, 1998; de Grandmont et al., 1994) will be used to assess patients' satisfaction relating to their prostheses. This is a treatment-specific patient-based outcome assessing satisfaction relating to several aspects of the mandibular prosthesis, including general satisfaction, comfort, stability, aesthetics, chewing ability (ease of chewing), chewing efficiency (ability to crush food in small particles), ease of cleaning, ability to speak and oral condition (condition of their mouth, which can refer to oral health status and was measured by "In general, are you satisfied with your oral condition?''. The subjects will answer on a 100 mm visual analogue scale (VAS) anchored by the words 'not at all satisfied' and 'extremely satisfied'.

  11. Oral health-related quality of life (OHRQoL)

    Time frame: Assessed at baseline (before implant surgery).

    The cross-culturally adapted Brazilian version of the Oral Health Impact Profile for edentulous subjects (OHIP-EDENT) will be used. It contains 19 items divided in four different subscale domains: (I) masticatory discomfort and disability (four items), (II) psychological discomfort and disability (five items), (III) social disability (five items), and (IV) oral pain and discomfort (five items). The items are answerable by a 3-point Likert scale and responses will be summed to result an overall score. Higher scores represent worse OHRQoL.

  12. Oral health-related quality of life (OHRQoL)

    Time frame: Assessed at the 3-month follow-up visit after implant placement.

    The cross-culturally adapted Brazilian version of the Oral Health Impact Profile for edentulous subjects (OHIP-EDENT) will be used. It contains 19 items divided in four different subscale domains: (I) masticatory discomfort and disability (four items), (II) psychological discomfort and disability (five items), (III) social disability (five items), and (IV) oral pain and discomfort (five items). The items are answerable by a 3-point Likert scale and responses will be summed to result an overall score. Higher scores represent worse OHRQoL.

  13. Oral health-related quality of life (OHRQoL)

    Time frame: Assessed at the 6-month follow-up visit after implant placement.

    The cross-culturally adapted Brazilian version of the Oral Health Impact Profile for edentulous subjects (OHIP-EDENT) will be used. It contains 19 items divided in four different subscale domains: (I) masticatory discomfort and disability (four items), (II) psychological discomfort and disability (five items), (III) social disability (five items), and (IV) oral pain and discomfort (five items). The items are answerable by a 3-point Likert scale and responses will be summed to result an overall score. Higher scores represent worse OHRQoL.

  14. Oral health-related quality of life (OHRQoL)

    Time frame: Assessed at the 12-month follow-up visit after implant placement.

    The cross-culturally adapted Brazilian version of the Oral Health Impact Profile for edentulous subjects (OHIP-EDENT) will be used. It contains 19 items divided in four different subscale domains: (I) masticatory discomfort and disability (four items), (II) psychological discomfort and disability (five items), (III) social disability (five items), and (IV) oral pain and discomfort (five items). The items are answerable by a 3-point Likert scale and responses will be summed to result an overall score. Higher scores represent worse OHRQoL.

  15. Prosthodontic maintenance events

    Time frame: Throughout 12 months after overdenture delivery.

    The incidence of prosthodontic repair/adjustment events will be recorded during the clinical assessments.

  16. Surgical time

    Time frame: Procedure (Assessed during the clinical visit of implant placement and overdenture delivery or denture adaptation.)

    The time interval concerning the clinical visit for implant placement and delivery of the overdenture or denture adaptation will me measured and registered.

Secondary outcomes

  1. Masticatory Performance

    Time frame: Assessed at baseline (before implant surgery).

    To perform the masticatory performance test two gums in a dragée form will be used, one blue and one pink, which need to be stuck together manually by wetting them with water and applying moderate force. The participants will be instructed to chew 2 samples of the gum on theirs preferred chewing side for 20 and 50 chewing cycles, respectively, leaving an interval of 1 minute between each chewing sequence.

  2. Masticatory Performance

    Time frame: Assessed at the 3-month follow-up visit after implant placement.

    To perform the masticatory performance test two gums in a dragée form will be used, one blue and one pink, which need to be stuck together manually by wetting them with water and applying moderate force. The participants will be instructed to chew 2 samples of the gum on theirs preferred chewing side for 20 and 50 chewing cycles, respectively, leaving an interval of 1 minute between each chewing sequence.

  3. Masticatory Performance

    Time frame: Assessed at the 6-month follow-up visit after implant placement.

    To perform the masticatory performance test two gums in a dragée form will be used, one blue and one pink, which need to be stuck together manually by wetting them with water and applying moderate force. The participants will be instructed to chew 2 samples of the gum on theirs preferred chewing side for 20 and 50 chewing cycles, respectively, leaving an interval of 1 minute between each chewing sequence.

  4. Masticatory Performance

    Time frame: Assessed at the 12-month follow-up visit after implant placement.

    To perform the masticatory performance test two gums in a dragée form will be used, one blue and one pink, which need to be stuck together manually by wetting them with water and applying moderate force. The participants will be instructed to chew 2 samples of the gum on theirs preferred chewing side for 20 and 50 chewing cycles, respectively, leaving an interval of 1 minute between each chewing sequence.

  5. Maximum voluntary bite force

    Time frame: Assessed at baseline (before implant surgery).

    Maximum voluntary bite force will be measured with a digital gauge (IDDK - Kratos, Cotia, São Paulo, Brazil) in the region of the first molar with three assessments per side.

  6. Maximum voluntary bite force

    Time frame: Assessed at the 3-month follow-up visit after implant placement.

    Maximum voluntary bite force will be measured with a digital gauge (IDDK - Kratos, Cotia, São Paulo, Brazil) in the region of the first molar with three assessments per side.

  7. Maximum voluntary bite force

    Time frame: Assessed at the 6-month follow-up visit after implant placement.

    Maximum voluntary bite force will be measured with a digital gauge (IDDK - Kratos, Cotia, São Paulo, Brazil) in the region of the first molar with three assessments per side.

  8. Maximum voluntary bite force

    Time frame: Assessed at the 12-month follow-up visit after implant placement.

    Maximum voluntary bite force will be measured with a digital gauge (IDDK - Kratos, Cotia, São Paulo, Brazil) in the region of the first molar with three assessments per side.

  9. Peri-implant bone change

    Time frame: Peri-implant bone loss at the 3-month follow-up compared to initial stage (1-week rediograph).

    Periapical radiographs will be obtained and the peri-implant bone level will be measured and compared longitudinally.

  10. Peri-implant bone change

    Time frame: Peri-implant bone loss at the 6-month follow-up compared to initial stage (1-week rediograph).

    Periapical radiographs will be obtained and the peri-implant bone level will be measured and compared longitudinally.

  11. Peri-implant bone change

    Time frame: Peri-implant bone loss at the 12-month follow-up compared to initial stage (1-week rediograph).

    Periapical radiographs will be obtained and the peri-implant bone level will be measured and compared longitudinally.

  12. Bleeding on probing

    Time frame: Assessed at 6-month post-insertion

    Incidence of inflammation of the peri-implant soft tissues

  13. Bleeding on probing

    Time frame: Assessed at 12-month post-insertion

    Incidence of inflammation of the peri-implant soft tissues

  14. Probing depth

    Time frame: Assessed at 6-month post-insertion

    Level of the peri-implant sulcus (in milimiters)

  15. Probing depth

    Time frame: Assessed at 12-month post-insertion

    Level of the peri-implant sulcus (in milimiters)

  16. Suppuration

    Time frame: Assessed at 6-month post-insertion

    Incidence of suppuration on probing the peri-implant soft tissues

  17. Suppuration

    Time frame: Assessed at 12-month post-insertion

    Incidence of suppuration on probing the peri-implant soft tissues

Sponsors and collaborators

Lead sponsor

Universidade Federal de Goias

Other

Collaborators

  • ITI International Team for Implantology, Switzerland
  • Institut Straumann AG

Registry information

Official study 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

Acronym: SMIS

Important dates

Study start
2021
Primary completion
2022
Study completion
2022
First posted
Feb 18, 2021
Registry last updated
May 10, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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