Buccal bone remodeling after tooth extraction using the flapless approach with and without synthetic bone grafting. A histomorphometric study in dogs

Bone regeneration of a polymeric sponge technique-Alloplastic bone substitute materials compared with a commercial synthetic bone material (MBCP+TM technology): A histomorphometric study in porcine skull

Background

Polymeric sponge technique is recommended for developing the desired porosity of Biphasic calcium phosphate (BCP) which may favor bone regeneration.

Purpose

To investigate the healing of BCP with ratio of HA30/β‐TCP70 (HA30) and HA70/β‐TCP30 (HA70) polymeric sponge preparation, compare to commercial BCP (MBCP+TM).

Materials and Methods

Materials were tested X‐ray diffraction (XRD) pattern and scanning electron microscope (SEM) analysis. In eight male pigs, six calvarial defects were created in each subject. The defects were the filled with 1 cc of autogenous bone, MBCP+TM (MBCP), HA30, HA70, and left empty (negative group). The new bone formations, residual material particles and bone‐to‐graft contacts were analyzed at 4, 8, 12 and 16 weeks.

Results

Fabricated BCP showed well‐distributed porosity. At 16 weeks, new bone formations were 45.26% (autogenous), 33.52% (MBCP), 24.34% (HA30), 19.43% (HA70) and 3.37% (negative). Residual material particles were 1.88% (autogenous), 17.58% (MBCP), 26.74% (HA30) and 37.03% (HA70). These values were not significant differences (Bonferroni correction <0.005). Bone‐to‐graft contacts were 73.68% (MBCP), which was significantly higher than 41.68% (HA30) and 14.32% (HA70; Bonferroni correction <0.017).

Conclusions

Polymeric sponge technique offers well‐distributed porosity. The new bone formation and residual material particles were comparable to MBCP+TM, but the bone‐to‐graft contact was lower than MBCP+TM.

Assessment of Bone Width for Implants in the Posterior Mandible

PURPOSE

After implants are placed into mandibular molar sites, it is assumed that crestal bone width will not change considerably over time. The purpose of this retrospective study was to determine crestal bone changes for implants placed into mandibular molar locations. The hypotheses for all groups (immediate, delayed, and grafted) were that no major changes in bone width of the posterior mandible would occur in the long term.

MATERIALS AND METHODS

This is a retrospective cohort study involving 3 groups of patients within the senior author's practice who had at least 4 years of follow-up cone-beam computed tomograms available for measurement. The primary outcome variable, crestal width, was measured at 3 intervals, namely at tooth removal, before implant placement, and 4 to 5 years after placement. Group A underwent tooth extraction with immediate implant placement; group B underwent tooth extraction with delayed implant placement; and group C underwent tooth extraction with socket grafting and implant placement 4 months after grafting. Standardized cross-sectional cone-beam computed tomograms were used to measure ridge width. Two-sample t tests and regression analysis were used to compare crestal width measurements at different periods among groups. Analysis of variance was adapted to check whether ridge widths among groups were confounded by variables, such as age, gender, and medical comorbidities.

RESULTS

Age, gender, medical comorbidities, and smoking were not statistically related to the outcome. Long-term comparisons indicated small yet significant (P = .0124) differences at the crestal level. The greatest change was for the grafted group, with width change from 12.4 ± 2.1 mm before extraction to 9.9 ± 1.8 mm 4 to 5 years after implant placement. Bone width changes 5 and 10 mm inferior to the crest did not change over time.

CONCLUSION

Within the time course and sample size evaluated, the thickness of the buccal bone seems to be maintained over time, regardless of method used, with small yet important changes from before tooth removal through the long-term.

Flap versus flapless procedure for ridge preservation in alveolar extraction sockets: a histological evaluation in a randomized clinical trial

OBJECTIVE

The aim of this study was to evaluate and compare the histological and histomorphometric features of two different procedures carried out in extraction socket grafting; namely, the flapped and flapless technique.

MATERIALS AND METHODS

Patients considered eligible for the study were randomized to receive tooth extraction and ridge preservation with the porcine bone and collagen membrane, with a full thickness mucoperiosteal flap and primary soft tissue closure (control group), or, with a flapless procedure and a secondary soft tissue closure (test group). After 3 months of healing, the surgical re-entry procedure was performed and implants were inserted in the test as well as in the control sites. Bone core samples were harvested from both groups and processed to be observed under light microscopy. Outcome variables were percentages of newly formed bone, residual graft particles and marrow spaces.

RESULTS

Thirty-four patients were enrolled in the study. All of the scheduled implants were placed. Histological and histomorphometrical analyses did not report significant differences between the two groups (with P-values ranging from 0.690 to 0.917). The mean percentages of newly formed bone, soft tissues and residual grafted particles were 22.5 and 22.5%, 59.3 and 59.4%, and 18.6 and 18.2% respectively for flap and flapless approach.

CONCLUSION

No histological and histomorphometrical differences were observed when comparing the flap and the flapless technique for tooth extraction and socket grafting procedures.