The Effects of Dis/Reconnection of Implant Abutments on Peri-implant Bone Levels

The Effects of Disconnection and Reconnection of Definitive Abutments on Peri-Implant Bone Levels: A 1-year Split-Mouth Randomized Controlled Clinical Study

The aim of this study was to evaluate the effects of definitive abutment connection at the time of implant placement on peri-implant bone levels and soft tissue changes in posterior maxilla and mandible regions.

A total of 38 implants were placed in 17 patients with at least 2 missing posterior teeth in the maxilla or the mandible for this study. Each patient received 2 or 4 implants. A definitive prefabricated abutment (test group) was randomly connected to one implant at implant placement (T0) and left undisturbed throughout the duration of the study. On the other implant, a healing abutment (control group) was connected and subjected to go through three disconnections and reconnections at 3 months (T3), 6 months (T6), and 12 months (T12) after the implant placement. Throughout the study period (1 year), all implants remained unrestored. Marginal bone level changes (MBLC) were assessed using standardized periapical radiographs taken at T0 and T12. Peri-implant soft tissue parameters including the keratinized mucosa width and lingual mucosa thickness were also recorded and evaluated.

Inclusion Criteria:

• Minimum age 18
• Good oral hygiene
• Healed site that possess two or more missing teeth in the maxillary or mandibular posterior region (excluding third molars)
• Adequate bone to accommodate at least a 4.3 mm diameter and 8mm length implant at each site
• Have at least 8mm interocclusal restorative space
• Willing to participate and attend the planned follow-up visits.

Exclusion Criteria:

• History of alcohol/drug dependency, or any medical, physical, or psychological factor that might affect the surgical or prosthodontic procedures and follow-up examinations
• History of radiation therapy to the head and neck region
• History or current habit of smoking
• History or current habit of bruxism
• No opposing occluding dentition or prostheses
• Need for bone augmentation during implant placement
• Implant insertion torque value <35 Ncm