Histomorphometric and Immunohistochemical Evaluation of Bone Healing Around Implants Placed Using Piezosurgery vs Conventional Drills: A Split-Mouth Pilot Study
This pilot study evaluated and compared histomorphometric and immunohistochemical characteristics of peri-implant bone tissue after implant site preparation using piezoelectric tips versus conventional drills. Six patients with bilateral partial edentulism underwent a split-mouth protocol. Twelve alveolar ridges were randomized into 6 control implant sites prepared using conventional drills (drill group) and 6 test implant sites prepared using piezoelectric implant inserts (piezo group). At 28 days after surgery (T1), single-stage “study fixtures” with 0.5 mm of peri-implant bone tissue were explanted and processed for histological, histomorphometric, and immunohistochemical analysis in both groups. For each sample inflammatory infiltrates, necrotic bone (zone 1), woven and newly formed bone (zone 2), native bone (zone 3), a vascular endothelium differentiation and neo-osteogenesis marker (cluster of differentiation 31 [CD31]), and an osteoblastic cell differentiation and osteogenesis marker (special AT-rich sequence-binding protein 2 [SATB2]) were evaluated. According to their histological bone features, the 3 histologically distinct areas were evident in both groups: zones 1, 2, and 3 according to their histological bone features. Zone 1 showed lower extension in the piezo group than in the drill group (p = .028). Regarding the immunohistochemical markers, in all areas of the piezo group, SATB2 and CD31 were statistically higher than in the drill group. Implant site preparation using piezo surgery results in less bone necrosis, greater osteoblastic activity, and greater vessel proliferation compared with the conventional surgical approach.
First surgical phase. The images show the technique of the implant site preparation and positioning of the fixtures in the piezo group (panels (a) and (b)) and in the drill group (panels (c) and (d)). The white star indicates the 3.3 × 8.5 mm study fixture.
Second surgical phase. The images show the moment of uncovering of the study fixture after 28 days of healing (a), a trephine drill used to remove the study fixture (b), and the biopsy sample obtained in occlusal (c) and lateral view (d).
Histological and immunohistochemical analysis. The figure contains the histological images of the samples taken from the 2 intervention groups. In the upper portion (histological analysis): Hematoxylin and Eosin Staining high magnification images of zone 1 (necrotic bone) and zone 2 (newly formed bone) in the 2 intervention groups. In the lower portion (immunohistochemical analysis), the images show the localization of the CD31 and SATB2 markers highlighted in zone 2 (newly formed bone) in the drill and piezo groups.
Histomorphometric pie chart. The graph shows the histomorphometric values relating to the necrotic bone (zone 1), newly formed bone (zone 2), and native bone (zone 3) in the drill (right-hand pie chart) and piezo (left-hand pie chart) groups.
Histomorphometric noninferiority analysis. Error bars indicated 1-sided 95% CIs of the difference in zones 1–3 mean values between the drill and piezo groups (piezo minus drill). The red broken line delineating the difference in the score shows the noninferiority margin (delta); the tinted area indicates the zone of inferiority. Graph 2a: Zone 1 (mean value −3.79): the upper CI limit lies to the left of the noninferiority margin and sits wholly below zero; the piezo group is not inferior and significantly superior to the drill group in maintaining bone vitality. Graph 2b: Zone 2 (mean value 1.14): the upper CI limit lies to the right of the noninferiority margin but crosses zero, demonstrating that the piezo group is not inferior and not superior to the drill group. Graph 2c: Zone 3 (mean value 2.62): the upper CI limit lies to the left of the noninferiority margin but crosses zero, demonstrating that the piezo group is not inferior and nonsuperior to the drill group in terms of native bone conserved.
Immunohistochemical noninferiority analysis. Error bars indicated 1-sided 95% CIs of CD31 and SATB2 expression mean values between drill and piezo groups (piezo minus drill). The red broken line delineating the difference in the score shows the noninferiority margin (delta); the tinted area indicates the zone of inferiority. Graph 3a: CD31 (mean value 1.67): the upper CI limit lies to the right of the noninferiority margin and sits wholly above zero, demonstrating that the piezo group is not inferior and superior to the drill group in terms of CD31 expression. Graph 3b: SATB2 (mean value 4.06): the upper CI limit lies to the right of the noninferiority margin and sits wholly above zero, demonstrating that the piezo group is not inferior and superior to the drill group in terms of SATB2 expression.
Immunohistochemical results. The histogram shows the median values and SD bars of the CD31 and SATB2 markers in zone 1 (necrotic bone), zone 2 (newly formed bone), and zone 3 (native bone) for each intervention group. The statistically significant differences are reported as follows: *p ≤ .05; **p ≤ .01.
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