Piezo-surgery Versus Conventional Drills
Condition: Bone Formation
Study type: Interventional

Summary: 
      Purpose: The aim of this RCT was to evaluate and compare histomorphometric and
      immunohistochemical characteristics of peri-implant bone tissue after implant site
      preparation using piezoelectric tips versus conventional drills. Material and Methods: A
      split-mouth protocol was carried out on 6 patients with bilateral partial edentulism. A total
      of 12 alveolar ridges were randomized into two groups: 6 control sites (Group B) with
      conventional drills preparation (Drill-group) and 6 test sites (Group A) treated by
      piezoelectric implant inserts preparation (Piezo-group). At 28 days after surgery (T1), in
      both group, one study-fixtures with 0.5 mm of peri-implant bone tissue were explanted and
      processed for the histological, histomorphometrical and immunoistochemical analysis. For each
      sample Inflammatory infiltrates, necrotic bone (Zone 1), woven and newly formed bone (Zone
      2), native bone (Zone 3), CD31 (cluster of differentiation 31) and SATB2 (special AT-rich
      sequence-binding protein necrotic bone undergoing remodeling) were evaluated.
    

Detailed description: 
      This was a pilot, parallel-group, doble-blinded, split-mouth, randomized clinical trial.

      The study included six patients with bilateral partial edentulism, having in total 12
      maxillary or mandibular edentulous alveolar ridges. All patients had been referred to the
      Unit of Oral and Maxillofacial Surgery, Alma Mater Studiorum, University of Bologna, Italy.

      The alveolar ridges were randomized into two groups using a computer-generated method: Group
      A included six regions where implant sites were prepared by piezosurgery, and Group B six
      regions prepared by conventional drilling.

      Surgical and prosthetic protocol In Group A, all implant sites were prepared with a
      piezoelectric device with IM1, IM2, IM2-3, or IM3 piezo-inserts according to the
      manufacturer's protocol (Piezosurgery, Mectron Medical Technology, Carasco, Italy). One or
      two implants were placed in each edentulous ridge along with an additional 3.3 x 8.5 mm
      implant, termed a "study fixture", in an adjacent area. In Group B, all implant sites were
      prepared with conventional drills according to the manufacturer's protocol (Premium, Sweden &
      Martina, Due Carrare, Padova, Italy); similarly to group A, one or two implants were placed
      in each edentulous ridge, and an additional 3.3 x 8.5 mm "study-fixture" was placed in the
      adjacent area.

      After cover screw placement, a parallel periapical radiograph was taken and the flap was
      sutured with 4-0 Vicryl. After surgery, antibiotic therapy (1 g amoxicillin and clavulanic
      acid every 8 h for 4 days), analgesic therapy (nimesulid 200 mg/day for 2 days, continued if
      pain persisted), and antiseptic therapy (chlorhexidine 0.2% [w/v] three times daily), were
      prescribed.

        -  Clinical procedure II - Re-entry Surgery At 28 days after surgery (T1), all
           "study-fixtures" in both groups were explanted using a trephine drill, taking care to
           explant the fixture with 0.5 mm of circumferential peri-implant bone tissue. The timing
           of re-entry surgery (T1) was fixed to be 28 days based on a previous animal study 12.
           All retrieved implants with bone tissue biopsies were fixed in 4% (v/v) formalin prior
           to histological analysis (Figure 7,8).

        -  Clinical procedure III - Prosthetic restoration At 3 months after surgery (T2), a
           mid-crestal horizontal incisions of keratinized tissue, without vertical incisions, was
           performed to expose the submerged implants and place healing screws. One month later
           (T3), implant-supported, metal-ceramic fixed restorations were delivered to the patients
           to allow functional loading.

        -  Data collection During surgery and at all postoperative visits (T0, T1, T2, and T3),
           clinical and radiographic data were recorded by a single operator (E.V.). Histological,
           histomorphometric, and immunohistochemical data were recorded on the same forms after
           bone biopsy and laboratory analyses (T1).

        -  Laboratory data

      All specimens were fully analyzed in terms of the percentages of necrotic bone area (NBA%)
      and newly-formed bone area (nFBA%), and the ratios of these values to total bone area (TBA).
      For each specimen, the authors identified three different areas proceeding from the surface
      of the fixture toward the border of the biopsy: zone 1, necrotic bone undergoing remodeling;
      zone 2, woven and newly formed bone; and zone 3, native bone. For each zone, we recorded:

        1. Absolute and relative areas: Zone areas were expressed as absolute values (mm2) and
           relative values (%) with respect to the total areas.

        2. Inflammatory infiltrates: The presence and type of inflammatory infiltrate (if present)
           was classified; we scored inflammation as absent (no inflammatory cells), minimal (< 5
           cells/mm2), or present (> 5 cells/mm2).

        3. CD31 (a vascular endothelium differentiation and neo-osteogenesis marker): CD31
           expression was recorded as the number of positive vessels/mm2

        4. SATB2 (a osteoblastic cell differentiation and osteogenesis marker): SATB2 expression
           was recorded as the number of positive spots/mm2.
    

Intervention name(s): Piezo-surgery insert OR Conventional Drills
Intervention type(s): Device
Intervention description(s): piezo-surgery: Group A (piezoelectric device with IM1, IM2, IM2-3, or IM3 piezo-inserts according to the manufacturer's protocol (Piezosurgery, Mectron Medical Technology, Carasco, Italy) Conventional drill: Group B (conventional drills according to the manufacturer's protocol (Premium, Sweden & Martina, Due Carrare, Padova, Italy)
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Pilot, parallel-group, single-blinded, split-mouth, randomized clinical trial
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: piezo-surgery; Implant surgery; histological analysis; Conventional drills