This is a three-armed randomized controlled clinical trial aiming the estimation of dimensional alveolar bone changes after insertion of post-extraction implants through 3 different surgical techniques: open flap, open flap and grafting, flapless.

Background and Objectives A recent systematic review investigating dimensional alveolar bone changes after insertion of post-extraction implants reported that there is a lack of randomized controlled trials that would serve as a scientific base for building clinical guidelines on alveolar site treatment after insertion of post-extraction implants. Different studies suggest that insertion of post-extraction implants should be performed after fully elevating a flap and inserting bone graft in the residual space between the implant surface and the alveolar socket. Other investigations report insignificant differences between open flap and flapless approaches, whereas the insertion of bone grafts remains controversial.

The present study is a three-armed randomized clinical controlled trial conducted with the following objectives:

1. Evaluation of morphological and alveolar bone level differences (marginal bone loss) on post-extraction implants inserted with the following techniques: 1) open flap surgery alone; 2) open flap surgery and bone grafting; 3) flapless.
2. Estimation of effectiveness of the three surgical techniques through measurement of secondary outcomes such as intra-operatory and post-operatory complications, pain and discomfort, time and costs.

Materials and Methods

• This is a three-armed randomized controlled clinical trial where each arm will belong to one of the treatments: 1) open flap surgery alone; 2) open flap surgery and bone grafting; 3) flapless.
• The randomizing sequence will be generated from a computer program (STATA 13) by a statistician who will also conduct blind statistical analysis of results.
• All patients will be recruited prior to trial commencement. They will be extensively informed regarding the intervention and will sign a treatment consent.
• Patients will be recruited according to the following inclusion criteria: absence of any systemic disease that might compromise implant integration or wound healing, appropriate periodontal health (measured through periodontal indexes), presence of premolars with indications of extractions, presence of adjacent teeth, absence of fenestrations, presence of vestibular alveolar wall with a minimum of 0.5mm of thickness. Patients who have undergone CT scanning in the past 5 years and heavy smokers (more than 20 cigarettes per day) will not be included in the study.
• Calculation of sample size has already been performed by an experienced statistician, accounting for a minimal predicted difference between groups of 1mm (SD 0.75mm) of marginal bone loss, alpha error of 0.05 and 90% of power. Based on these calculations, a total of 45 patients will be included in the study.
• Interventions will be performed in accordance with ethical standards as suggested by the Helsinki Declaration (1975). Approval of Ethical Committee of the University of Bari has already been obtained (reg.nr. 4987).
• All surgical interventions will be performed by the same experienced surgeon who will be informed of the type of intervention after tooth extraction (allocation concealment through dark sealed envelopes).
• The primary outcome is marginal bone loss (MBL) and alveolar bone dimensional changes measured through CT Cone Beam performed immediately after implant insertion and 6 months after. Secondary outcomes are intra-and post-operative complications, pain and discomfort, time and costs.
• Outcomes will be measured by another clinician blinded in terms of treatment allocation.
• Statistical analysis will be performed by an independent statistician. Statistical tests will include: One-way Anova, Bonferroni tests and several linear and logistic regressions in order to estimate potential predictive variables. Statistical significance will be set at .05.
• Interruption of study will be considered in the following situations: 1.preliminary observation of highly significant difference between techniques indicating one technique highly superior; 2. big number of lost to follow-up (bigger than that considered during sample size calculation)
• Patients will be excluded from the study in the following cases: missing follow-up hygiene controls at 1 and 3 months post-intervention, missing 6 months follow-up control, poor cooperation in terms of domestic oral hygiene (periodontal indexes measured), income of systemic or local diseases that might compromise outcomes.

Inclusion Criteria:

• absence of any systemic disease that might compromise implant integration or wound healing
• appropriate periodontal health (measured through periodontal indexes)
• presence of premolars with indications of extractions, presence of adjacent teeth
• absence of fenestrations
• presence of vestibular alveolar wall with a minimum of 0.5mm of thickness

Exclusion Criteria:

• patients who have undergone CT scanning in the past 5 years
• heavy smokers (more than 20 cigarettes per day)
• patients not showing up at 1 and 3 months hygiene sessions
• patients not showing up at 6 months follow-up

The care provider could not be blinded because of the nature of the treatment. The patient was blinded and the investigator and outcome assessor as well (using a code to identify teeth and patients).