Effectiveness of 3D-printed Patient-specific Resorbable Scaffolds for Maxillary Bone Regeneration

A parallel-arm randomized clinical trial will be designed. The participants will be elderly patients from the city of Valdivia, Chile, regardless of sex, from the Dental Health Service of the Base Hospital of Valdivia for dental rehabilitation with dental implants. Clinical characteristics and complete medical history (such as sex, age and comorbidities) will be recorded and all the information that allows the identification of the patients will be encrypted.

Patients requiring bone regeneration at the time of examination should have an atrophic bilateral mandible with poor bone available according to periodontal diseases classification behind tooth #3.3 or #4.3; with an edentulous alveolar ridge with a remaining bone height of ≤ 6 mm. Patients will be excluded if they have had previous dental implant surgeries, with maxillary sinus pathologies, with oral tissue lesions, diseases that produce acute/chronic pain, smokers of more than 5 cigarettes per day, with excessive alcohol consumption (more than three times per week), and who suffer from any systemic disease whose surgical intervention is prohibited, for example: severe heart disease, congenital coagulation factor deficiency, dialysis, or malignant tumor in terminal phase. Also excluded are patients with diabetes that is not well controlled or who have difficulty achieving an Hb ≥ 7 g/dL in a preoperative examination; patients taking any anti-platelet or anticoagulant drug and patients with a history of heart disease.

• Sample size calculation Considering as the main objective of this study the formation of vital and functional bone analyzed in histological specimens, for the sample calculation the researcher relied on the previously randomized clinical trial who demonstrated a difference in the percentage of bone formation using PCL bone matrices in bone preservation was 9.5%. As a result of using this effect size with a given alpha level of 0.05, a power of 80% and an allocation ratio of 1, the sample size was 4 patients per group (algorithm: mean power 1 9.5, sd(3.6). STATA v.14.0..

Furthermore, taking into account that each patient will use both sides of their jaw (left and right), with two study groups and a 25% loss to follow-up or sample processing error, estimating that a total of 10 patients will participate in this study.

• Study groups and randomization

  • Osteoprint group: Patients with a jaw/maxilla atrophy in which the 3D scaffold with PCL will be inserted.

  • Control group: Patients with a jaw/maxilla atrophy which will be regenerated using the conventional technique using a titanium reinforced polytetrafluoroethylene (PTFE) membrane (Cytoplast® brand) and filling the space with Bio-Oss xenograft (Geistlich Pharma Agency. Germany).

• Randomization: The mechanism to perform the randomization sequence will be using the "RANDBETWEEN" function of Microsoft Excel® v.15.24.2016 (Microsoft, Sacramento. USA). An researcher will randomize in a spreadsheet with three columns: the first column with the patient number, the second column with the maxilla/mandible side to be used (#1 right side; #2 left side) and the third column with the type of study group to be used (#1: experimental group; #2: control group). This sequence will be previously determined by an investigator and will be informed before surgery, according to the number of patients to be operated.

• Experimental Design To analyze the osteogenic capacity of the 3D printed bone scaffold with PCL, an researcher will compare the volume of bone formed in the area using the 3D printed bone scaffold with PCL+ βTCP (experimental group) versus the volume of bone regenerated using a titanium-reinforced polytetrafluoroethylene (PTFE) membrane (control group). The outcome will be measured in histomorphometry and immunohistochemistry of bone biopsies obtained at six months.