Titanium Zirconium (TiZr) Mini Implants

Study Overview
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Brief Summary
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H0: Within the first year post-placement, four interforaminally placed, immediately loaded 2.4 mm narrow-diameter one-piece TiZr implants with miniaturized stud-type attachments show improved patient-reported outcome measures (PROMS) compared to two interforaminally placed, early loaded, TiZr two-piece implants with stud-type attachments to retain a mandibular overdenture.The specific aim is to compare both treatment alternatives to evaluate which one may be recommended for elderly edentulous patients.

Official Title
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Is the Stabilization of a Mandibular Overdenture Employing Four Novel One-piece Immediately Loaded TiZr Implants With Miniaturized Stud-type Attachments a Feasible Alternative to Two Two-piece Early Loaded Tissue-level Implants With Regular Stud-type Attachments?

Conditions
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Dental Implants

Intervention / Treatment
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* Procedure: early loading
* Procedure: immediate loading


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: At patient level: Written informed consent Age ≥ 18 years Sufficient complete dentures (Marxkors and Ferger, 1989) not older than 1 year Patient is unsatisfied with mandibular denture to the degree that he/she seeks treatment At site level: Healed edentulous mandible (minimum 8 weeks since last extraction) Minimal ridge dimensions 5.5 mm (width) by 12 mm (height) in the anterior (interforaminal) area, allowing the placement of 3.3 (endosseous diameter) by 10 mm (length) implants Opposing dentition: complete denture on a edentulous maxilla Physical status (PS) 1 and 2 (American Society of Anesthesiologists) Exclusion Criteria: At patient level Any physical or mental disorder that would interfere with the ability to perform adequate oral hygiene or the capability of providing written informed consent and compliance to the protocol Any disorder that would interfere with wound healing or represent a contraindication for oral surgery such as, but not limited to, uncontrolled diabetes or conditions resulting in or requiring immunosuppression, radiation, chemotherapy, frequent use of antibiotics or antiresorptive medication such as bisphosphonates Pregnancy or lactation Heavy smoking habit with > 20 cig/d Severe bruxism or clenching habits, present oro-facial pain At site level: Ridge defects requiring staged bone augmentation procedures (simultaneous Guided Bone Regeneration (GBR) within the ridge contour allowed)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Control-group<br>Two Tissue Level TiZr Sand blasted long grit acid-etched (SLA) implants placed in positions 33 and 43 (diameter 3.3mm, length ≥10mm), early loading | Procedure: early loading<br>* two TiZr implants on SLA surface<br>|
| Experimental: Experimental-group<br>Four narrow-diameter implants (NDI) TiZr SLA implants in positions 34, 32, 42, and 44 (diameter 2.4mm, length ≥10mm), immediate loading | Procedure: immediate loading<br>* four TiZr implants on SLA surface<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Geriatric Oral Health Assessment Index (GOHAI) | Change from baseline questionnaires in Oral Health Related Quality of Life (OHRQoL). Scores 0-60: higher values represent lower OHRQoL | One-year follow-up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Additional Oral Health Impact Profile for edentulism (OHIP-EDENT) | Change from baseline questionnaires | Follow-up (up to 365 days) | 
| Additional PROM Denture Satisfaction Index (DSI) | Change in Denture Satisfaction higher values represent better satisfaction (0-1200mm) | Baseline, follow-up (up to 365 days) | 
| Implant Survival | Survival (yes/no) | at implant loading (at 24 hours for arm B, at 6-8 weeks for arm A), at the one-year follow-up | 
| Implant Success | Success according to Misch (2007) Misch criteria scores 1-4: higher values represent better success | at implant loading (at 24 hours for arm B, at 6-8 weeks for arm A), at the one-year follow-up | 
| Prosthetic Survival | Prosthetic Survival (yes/no): is the denture still in place? | Baseline, follow-up (up to 365 days) | 
| Chewing Efficiency | Color mixing test | Baseline, follow-up (up to 365 days) | 
| Plaque Index | Plaque Index Scores 0-3 3= thick plaque is visible along gingival margin 2= plaque is visible along gingival margin, with or without air drying 1= following air drying, plaque is not visible but can be wiped off with an explorer 0= following air drying, plaque is not visible nor can be wiped off with an explorer | at implant loading (at 24 hours for arm B, at 6-8 weeks for arm A), at the one-year follow-up | 
| Bleeding Index | Bleeding Index Scores 0-3 0= Healthy gingival Gingival look inflamed, but don't bleed when probed Gingival look inflamed and bleed when probed Ulceration and spontaneous bleeding | at implant loading (at 24 hours for arm B, at 6-8 weeks for arm A), at the one-year follow-up | 
| Pocket Probing depth | depth measured in mm | at implant loading (at 24 hours for arm B, at 6-8 weeks for arm A), at the one-year follow-up | 
| Time-Cost-Analysis | Total treatment time will be collected and added. Total treatment cost will be evaluated and a ratio will be calculated. The groups will be compared on the base of this ration | After surgery, after implants loading, after follow-up (up to 365 days) | 
| Cost Effectiveness and Willingness to Pay | Cost effectiveness wil be calculated as a ratio of treatment cost in relation to change of GOHAI sum score. This will allow to evaluate how much monetary item is needed to achieve a change in GOHAI | Total change and time at 1y follow-up | 
| In-vivo evaluated loss of retentive force | Measurement with a hand-held digital force gauge | after implant loading (expected to be after 6 weeks on average) and at follow-up (up to 365 days) |