Denosumab-associated jaw bone necrosis in cancer patients: retrospective descriptive case series study.

BACKGROUND: Denosumab (DMB) is a bone antiresorptive agent used to treat osteoporosis or metastatic cancer of the bones. However, denosumab-associated osteonecrosis of the jaw (DRONJ) has become a common complication in cancer patients. The prevalence of osteonecrosis of the jaw (ONJ) in cancer patients is estimated to be similar for both bisphosphonate-related cases (1.1 to 1.4%) and denosumab-related cases (0.8 to 2%), with the addition of adjunctive therapy with anti-angiogenic agents reportedly increasing its prevalence to 3%. (Spec Care Dentist 36(4):231-236, 2016). The aim of this study is to report on DRONJ in cancer patients treated with DMB (Xgeva®, 120mg). CASE PRESENTATION: In this study, we identified four cases of ONJ among 74 patients receiving DMB therapy for metastatic cancer. Of the four patients, three had prostate cancer and one had breast cancer. Preceding tooth extraction within 2 months of the last DMB injection was found to be a risk factor for DRONJ. Pathological examination revealed that three patients had acute and chronic inflammation, including actinomycosis colonies. Among the four patients with DRONJ referred to us, three were successfully treated without complications and had no recurrence following surgical treatment, while one did not follow up. After healing, one patient experienced a recurrence at a different site. Sequestrectomy in conjunction with antibiotic therapy and cessation of DMB use proved to be effective in managing the condition, and the ONJ site healed after an average 5-month follow-up period. CONCLUSION: Conservative surgery, along with antibiotic therapy and discontinuation of DMB, was found to be effective in managing the condition. Additional studies are needed to investigate the contribution of steroids and anticancer drugs to jaw bone necrosis, the prevalence of multicenter cases, and whether there is any drug interaction with DMB.

Effect of the size of the bony access window and the collagen barrier over the window in sinus floor elevation: a preclinical investigation in a rabbit sinus model.

PURPOSE: The aim of this study was to investigate the effect of (1) the size of the bony access window and (2) collagen membrane coverage over the window in sinus floor elevation in a rabbit sinus model. METHODS: Small bony access windows (SW; ø 2.8 mm) were made in 6 rabbits and large windows (LW; ø 6 mm) in 6 other rabbits. Both sinuses in each rabbit were allocated to groups with or without coverage of a collagen membrane (CM) on the window, resulting in 4 groups: SW, LW, SW+CM, and LW+CM. After 4 weeks of healing, micro-computed tomographic, histologic, and histomorphometric analyses were performed. RESULTS: Bony healing in the window area was incomplete in all groups, but most bone graft particles were well confined in the augmented cavity. Histologically, the pattern of new bone formation was similar in all groups. Histomorphometrically, the percentage of newly formed bone was greater in the groups with CM than in the groups without CM, and in the groups with SW than in the groups with LW (12.92%±6.40% in the SW+CM group, 4.21%±7.73% in the SW group, 10.45%±4.81% in the LW+CM group, 11.77%±3.83% in the LW group). The above differences were not statistically significant (P>0.05). CONCLUSIONS: The combination of a small bony access window and the use of a collagen membrane over the window favored new bone formation compared to other groups, but this result should be further investigated due to the limitations of the present animal model.

Effectiveness of hydraulic pressure-assisted sinus augmentation in a rabbit sinus model: a preclinical study.

OBJECTIVES: To investigate the effectiveness of hydraulic pressure-assisted sinus augmentation (SA) in a rabbit sinus model in terms of radiographical and histological healing. MATERIALS AND METHODS: Bilateral SA was performed in 12 rabbits. Each sinus was randomly assigned to either a hydraulic pressure-assisted SA (test) or a conventional SA (control) group. Healing periods of 2 and 4 weeks were applied (n = 6 for each week). Healing pattern including newly formed bone (NB) and residual bone substitute material (RM) was analyzed with microcomputed tomographically, histologically, and histomorphometrically. RESULTS: No sinus membrane perforation was detected in either group. In the microcomputed tomographic analysis, the test group exhibited higher apico-coronal spread of RM compared to the control group (p < 0.05). Particularly, the test group exhibited several masses of NB out of the cluster of RM. Histologically, the test group showed an elongated shape of the augmented space, whereas the control group generally presented a dome shape. Histomorphometrically, the total augmented area and the area of NB (1.32 ± 0.56 vs. 0.84 ± 0.40 mm2 at 2 weeks, 2.24 ± 1.09 vs. 2.22 ± 0.85 mm2 at 4 weeks) were not significantly different between the test and the control groups at both healing periods (p > 0.05). CONCLUSION: Hydraulic pressure-assisted SA led to new bone formation in the distant areas from the bony access hole, but similar histological healing pattern to conventional SA. CLINICAL RELEVANCE: Hydraulic pressure-assisted SA is a promising option for treating pneumatized posterior maxilla.

Factors affecting maxillary sinus pneumatization following posterior maxillary tooth extraction.

PURPOSE: The aims of the present study were 1) to quantitatively evaluate the extent of sinus pneumatization and 2) to determine the factors affecting sinus pneumatization. METHODS: Based on implant treatment records, a list of patients who underwent implant placement on the posterior maxilla was obtained. Among them, patients with pre-extraction and post-extraction (before implant placement) panoramic radiographs were selected. After excluding radiographs with low resolution and image distortion, the radiographs before and after extraction were superimposed using computer software. Subsequently, the extent of sinus pneumatization (the vertical change of the sinus floor) was measured. Simple and multiple mixed models were used to determine the factors affecting sinus pneumatization. RESULTS: A total of 145 patients were eligible for the present investigation. The average extent of sinus pneumatization was 1.56±3.93 mm at 176 tooth sites. Male sex, single tooth extraction, extraction of an endodontically compromised tooth, a class I root-sinus relationship, and sinus membrane thickening >10 mm favored pneumatization, but without statistical significance. The maxillary second molar presented the greatest pneumatization (2.25±4.39 mm) compared with other tooth types. This finding was confirmed in the multiple mixed model, which demonstrated a statistically significant impact of the extraction of a second molar compared with the extraction of a first premolar. CONCLUSIONS: Maxillary sinus pneumatization was 1.56±3.93 mm on average. The extraction of a second molar led to the greatest extent of pneumatization, which should be considered in the treatment plan for this tooth site.

Collagenated Synthetic Bone Substitute Material for Sinus Floor Elevation at Sites with a Perforated Schneiderian Membrane.

Schneiderian membrane perforation (SMP) is the most common complication during sinus floor elevation (SFE). Conventional methods to repair SMP, such as using a collagen barrier, may be clinically demanding. The aim of the present study was to compare the effects of collagenated bone substitute materials with and without a collagen barrier to repair SMP during SFE in terms of new bone formation and dimensional stability. In 12 rabbits, intentional SMP was made during bilateral SFE. The rabbits were randomly assigned under two groups: the control group, in which the sinus was repaired with a collagen barrier, and the test group, in which the sinus was repaired without a collagen barrier. Collagenated bone substitute material was grafted in both groups. Healing periods of 2 weeks and 4 weeks were provided in both groups. There were no adverse clinical events. Histology revealed that the Schneiderian membrane had atrophied with loss of cilia and serous glands in both groups at 4 weeks. Histomorphometry revealed that the newly formed bone (test: 0.42 ± 0.17 mm2, control: 0.36 ± 0.18 mm2 at 2 weeks; test: 1.21 ± 0.36 mm2, control: 1.23 ± 0.55 mm2 at 4 weeks) or total augmented area did not significantly differ between the two groups at either time points (p > 0.05). In conclusion, collagenated bone substitute material without a collagen barrier demonstrated similar new bone formation and dimensional stability as that with a collagen barrier in repairing SMP.