Material and Methods
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- Study designA pilot, prospective, single-blind, split-mouth and randomized clinical trial was conducted in patients who required treatment with two implants in each zygomatic bone. Participants were followed up at 72 hours, 7 days, 15 days, 3-, 6- and 12-months post-surgery; The present trial was conducted in accordance with Helsinki Declaration (2013) and the Ethical committee approvement from Clínico San Carlos Hospital (19/531-R_P).- ParticipantsParticipants were recruited through the research project carried out by the Oral Surgery postgraduate clinic at Universidad Complutense Madrid. All patients enrolled were over 18 years-old, with an ASA I or ASA II surgical risk according to the American Society of Anesthesiologists (ASA). Moreover, patients who had less than 4 mm of residual maxillary bone measured with cone-beam computer tomography needed treatment with two zygomatic implants in each malar bone. All participants were informed in detail about the nature of the study and gave their written informed consent before being included.- Surgical procedurePatients were treated under intravenous conscious sedation with benzodiazepine (Midazolam 1 mg/ml, Anesfarma, Spain) combined with local anesthesia of articaine hydrochloride with epinephrine 0,1 mg/ milliliter(ml) (Ultracain 40 mg, Normon, Spain). The surgical procedure was performed by a highly-experienced maxillofacial surgeon with over 30 years of clinical experience (J.L-Q.). All zygomatic implants were placed in the patient in only one surgical session. Moreover, each participant was part of two study groups: the control group (A) in which after two zygomatic implants, the covering flap was sutured and the experimental group (B) in which, after implant placement, the buccal fat pad was repositioned covering the out-bone implant body, (Fig. 
Surgical procedure. In the study side the buccal fat pad is covering body implants.All previous surgery steps were the same for both groups and the surgeon placed HE Zygomatic Implant Neodent® (Straumann AG; Basel, Switzerland) following its drill sequence system. After all zygomatic implants were placed, the implants were classified in accordance with ZAGA classification system (- Outcome measuresThe primary outcome was peri-implant soft tissue thickness difference between both groups, using the average of three measurement points on the buccal side of the implant platform registered with a periodontal probe (HH12 periodontal probe, Deppeler SA). Secondary outcomes were: pain assessed using a Visual Analog Scale (VAS), swelling assessed using the Amin & Laskin method (
Flow chart of the study protocol according to Consort guidelines, including the number of participants enrolled and the period of the outcome measures.- Sample size, randomized sequence, and statistical analysisBeing a pilot study, no sample size was calculated, and seven patients were enrolled in this study. Hence, a total of 28 zygomatic implants were analyzed been it considered the statistical unit.The sample was randomized through a simple process using Matlab 28b (Math Works. Natick, Massachusetts, USA). A descriptive statistical analysis was carried out using measures of central and dispersion tendency and percentages. In addition, Shapiro-wilk test was used to assess the normal distribution of the data and a non-parametrical test (Wilcoxon) to contrast hypothesis.