Dimensional Changes in Single Crowns Supported by Short Transmucosal Implants With Diverging or Converging Neck Profiles in the Esthetic Zone

Long-term Dimensional Changes in Single Crowns Supported by Short (6 mm) Transmucosal Implants With Divergent or Convergent Neck Profiles in the Esthetic Zone. A Randomized Randomized Controlled Clinical Trial

The goal of the present randomized clinical trial is to assess the long-term osseous and peri-implant soft tissue changes as well as the success rate of short implants (6 mm) with a converging collar with micro threads or a diverging polished collar placed in the esthetic zone of the maxilla on partially edentulous patients. The main questions it aims to answer are:

• what are the long-term bone and soft tissue changes around implants with a converging collar with micro threads compared to a diverging polished collar placed in the esthetic zone of the maxilla?
• What is the success rate of implants with a converging collar with micro threads compared to a diverging polished collar placed in the esthetic zone of the maxilla? Dental implants with a converging collar with micro threads or a diverging polished collar will be placed in the esthetic zone of the maxilla of the included participants and the measurements regarding the bone and soft tissue level will be compared.

The objectives of the present randomized clinical trial are to evaluate the clinical and radiographic changes over time of hard and soft tissues around implants with a convergent or divergent collar. Twenty volunteer participants with two edentulous regions in the maxillary esthetic zone (from the right second premolar to the left second premolar) will be included in the study. Two implants will be randomly installed, one with a convergent collar and one with a divergent collar. After 3 months of healing, individual crowns will be installed. At each visit the following parameters will be evaluated: plaque index, probing depth, bleeding on probing, the recession of the mucosal margin, intraoral radiographs, likewise control CBCT, and impressions will be performed. The visit will take place at 6 and 12 months and then annually for a minimum of 3 years. Changes at the level of the marginal bone will be assessed overtime on the radiographs. Dimensional changes will be clinically evaluated during control evaluations and later through digital impressions.

Inclusion Criteria:

• Presence of at least two edentulous areas in the esthetic region of the maxilla (from right to left from second premolar to premolar, preferably first premolars and incisors)
• Alveolar bone ≥ 8 mm in height and ≥ 5 mm in thickness assessed on CBCT.
• Age of ≥ 21 years.
• Need for an implant-supported prosthetic restoration.
• Be in good general health with no contraindications to oral surgical procedures.
• Not be pregnant.
• Patients who agree to participate in the study and sign the informed consent.

Exclusion Criteria:

• The presence of any uncontrolled systemic disease.
• History of past or ongoing chemotherapeutic or radiotherapeutic treatments.
• Heavy smokers (>10 cigarettes per day).
• Previous bone regeneration procedures in the area of interest