Socket Reconstruction Technique and Immediate Implant Placement With Two Different Bone Substitute Materials.

The present research is a national multicentric prospective parallel double-blinded (both the patient and the investigator who will perform the measurements are blind) randomized controlled clinical trial. It is a superiority comparative study on a medical device CE marking, used according to the intended use subject to the CE marking.

The hypothesis tested is: the socket reconstruction procedure performed in conjunction with IIP with the use of DBBM+HA leads to a greater increase in the vertical buccal bone height than same procedure with DBBM alone.

The present study will be reported according to the CONSORT statement for improving the quality of reports of parallel-group randomized trials (http://www.consort-statement.org/).

Patients will be randomly treated by means of IIP+connective tissue graft (CTG)+DBBM+HA (Test group or A group) or IIP+CTG+DBBM (Control group or B group). A randomization list will be generated in blocks: patients will be divided in 3 blocks according to the study center (M=San Raffaele Hospital, Milan; B=University of Bologna; S=University of Siena) and the treatment will be assigned at random in each block to ensure a balanced distribution of the tested interventions, with a ratio test:control=1:1. The investigator who will generate the allocation sequence will not be the person who will determine eligibility and entry of patients. The assignments (A or B group) will enclose in serially numbered, opaque, sealed envelopes, each bearing on the outside only the letter corresponding to the name of the center (M, B, S) and a number (from 1 to 10). A designated investigator for each center will be responsible to ensure that the envelopes will be opened sequentially, and only after the patient will undergo extraction of the hopeless tooth, implant placement, and clinical measurement assessment. For each patient, a sequential number will be assigned based on the date of enrollment, and the envelope with the corresponding number will be opened for each of them.

Both the investigator who will perform the measurements and the patients will be blinded to the randomization. The principal investigator (PI) will make sure patients are blind by simply not telling them there is a difference between the two medical devices; while he will ensure that investigator (who will perform the measurements) is blind by assigning a code or an identifying number to the two treatment groups so that they cannot know which device has been used.

Patients will be followed for 6 months after surgery.

The undermentioned 5 follow-up visits, which are standard of practice for all implant-bearing patients, will be scheduled for each patient for both treatment groups at:

• 7±2 days post-surgery - clinical and photographic examination, collection of VAS (Visual Analogue Scale).
• 14±4 days post-surgery - suture removal, clinical and photographic examination.
• 1 month±7 days post-surgery - clinical and photographic examination.
• 3 months±5 days post-surgery - clinical and photographic examination, measurements of the following parameters: Gingival recession depth (REC in mm), Keratinized tissue width (KTW in mm), Soft tissue thickness (GT in mm), Pocket probing depth (PPD in mm), Bleeding on probing (BoP), Plaque index (PI).
• 6 months ±1 month post-surgery - clinical and photographic examination, CBCT scan, periapical radiography, 3D digital dental impression, measurements of the following parameters: Gingival recession depth (REC in mm), Keratinized tissue width (KTW in mm), Pocket probing depth (PPD in mm), Bleeding on probing (BoP), Plaque index (PI).

After the visit at 6 months, each patient will then be considered "off study" (e.g. subject has completed treatment and all follow-up visits).

Inclusion criteria

• Participant is willing and able to give informed consent for participation in the trial.
• In good general health as evidenced by medical history.
• Presenting a single hopeless tooth candidate for extraction in the maxillary or mandibular area (from second premolar to second premolar, intercalated or the last tooth of dental arch) in need of a single implant-supported fixed prosthetic rehabilitation.
• Presence of >3mm of buccal wall dehiscence evaluated using Cone Beam Computed Tomography (CBCT).
• In healthy periodontal conditions (i.e., no presence of sites ≥ 4 mm and/or presence of intra-bony defects in the selected sites, full mouth plaque score < 20% and full-mouth bleeding score < 20%).

Exclusion criteria

• Current or previous use of immunosuppressant, bisphosphonate, or high-dose corticosteroid therapy.
• Presence of inflammatory and autoimmune disease of the oral cavity.
• Severe or poorly controlled diabetes or previous radiotherapy of head area.
• Contraindications to dental and/or surgical interventions (e.g. severe endocrine bone diseases, severe metabolic bone disorders, malignant tumour diseases).
• Individuals who are smokers of >10 cigarettes/day.
• Female participant who is pregnant, lactating or planning pregnancy during the course of the study.
• Presence of <3mm of dehiscence of buccal walls of the socket after tooth extraction.
• Presence of a distance between the interdental bone crest and buccal bone crest <3 mm after tooth extraction.