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

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