Expression of osteogenic markers after administration of selective estrogen receptor modulators during implant placement in the osteoporotic rat maxilla

PURPOSE

This study examined the effects of raloxifene during bone formation around the dental implant in the ovariectomy-induced osteoporotic rat maxilla.

METHODS

Fifty-four female 10-week-old Sprague-Dawley rats were divided into three groups (n = 18 each); sham-operated (control), ovariectomized (OVX), and ovariectomized and raloxifene-administered (RAL). Eight weeks after ovariectomy, both upper first molars were extracted, and implants were placed 4 weeks post-extraction. The RAL group was given 1 mg/kg of raloxifene per day while the other groups received a vehicle. Six rats in each group were sacrificed at days 4, 7, and 14 and submitted for quantitative reverse transcription polymerase chain reaction and immunohistochemical staining, for evaluation of osteogenic genes expressions.

RESULTS

The alkaline phosphatase expression was upregulated in the RAL group compared to the OVX group at day 4. The osteocalcin expression was significantly higher between the RAL group and the OVX group at day 7. Immunohistochemical staining revealed increased expression during the initial bone-forming process and indicated more active bone formation in the RAL group than in the OVX group.

CONCLUSION

Raloxifene administration enhanced the osteogenic genes and proteins expression in the bone around the implant. Further studies are required to establish the long-term clinical effects of raloxifene administration.

Enhancement of peri-implant bone formation via parathyroid hormone administration in a rat model at risk for medication-related osteonecrosis of the jaw

Purpose

Dental implant-associated medication-related osteonecrosis of the jaw has been frequently reported in patients administered bisphosphonates (BPs) to prevent osteoporosis. The aim of this study was to investigate the effect of intermittent administration of parathyroid hormone (PTH) on peri-implant bone in the maxillae of ovariectomized rats systemically administered BPs.

Methods

Thirty 8-week-old female Sprague-Dawley rats were randomly divided into 3 groups. The OVX-ZP group included ovariectomized rats administered 60 µg/kg of zoledronate once a week for 6 weeks and 30 µg/kg PTH after implant installation. The OVX-Z group included ovariectomized rats administered 60 µg/kg of zoledronate once a week for 6 weeks and saline after implant installation, and the control group included rats that underwent a sham operation and were then administered saline. Rats were sacrificed 4 weeks after implant placement for histomorphometric and micro-computed tomography (CT) analyses.

Results

The average bone area percentage was greater in the OVX-ZP group than in the OVX-Z group (53.4%±4.0% vs. 28.9%±9.5%, P=0.01). The bone-to-implant contact ratio was 50.8%±1.4% in the OVX-ZP group and 16.9%±2.4% in the OVX-Z group (P=0.012). The average bone volume ratio as shown on micro-CT was 31.3%±19.8% in the OVX-ZP group and 19.4%±9.3% in the OVX-Z group (P=0.045). The OVX-ZP and OVX-Z groups displayed similar trabecular thickness (0.06±0.004 mm vs. 0.06±0.002 mm) (P>0.05) and trabecular separation (0.21±0.02 mm vs. 0.29±0.13 mm) (P>0.05). However, the number of trabeculae in the OVX-ZP group was significantly higher than that in the OVX-Z group (4.3±1.33/mm³ vs. 2.2±0.19/mm³) (P=0.024).

Conclusions

The present findings indicate that intermittently-administered PTH can promote peri-implant bone formation and suggest that PTH administration may aid in effective treatment for medication-related osteonecrosis of the jaw after dental implantation.

Association of temporomandibular disorder and high frequency of suicide ideation in Korean adolescents: a cross-sectional survey

BACKGROUND

This study investigated the association between psychological factors and temporomandibular disorder (TMD) in a representative sample using data from the Korean nationwide survey.

METHODS

The study included 1337 adolescents. Participants provided demographic, socio-economic and behavioural information, and responses to questionnaires assessing their mental health status including perceived stress, depressed mood and suicidal ideation in the presence of TMD. In univariate analysis, t-test was used to test the association between TMD and risk factors by gender in a complex sampling design. Multivariate logistic regression analyses were used to examine the association between TMD and psychological factors.

RESULTS

Male adolescents with TMD were highly engaged with depressed mood and suicidal ideation (p = .0006, p = .0223), however, no psychological factors were significant in female adolescents (p < .05). Male adolescents with both depressed mood and suicidal ideation had significantly high rates of TMD (p = .0024). The risks for experiencing depressed mood (OR: 3.07) and suicidal ideation (OR: 2.564) were significantly associated with TMD in male adolescents after adjusting confounders.

CONCLUSIONS

The results provide evidence that the depressed mood and suicidal ideation were associated with TMD in male adolescents. This study has important implications for enhanced screening and evaluation of mental health among patients with TMD according to gender.

Influence of human parathyroid hormone during orthodontic tooth movement and relapse in the osteoporotic rat model: A preliminary study

OBJECTIVE

To investigate the effects of parathyroid hormone (PTH) on tooth movement in ovariectomized (OVX) rats by comparing the tooth movement distance and relapse and by examining the alveolar bone microstructure.

MATERIALS AND METHODS

Thirty 8-week-old female rats were classified into 3 groups: sham-operated, OVX and ovariectomized rats injected with PTH (PTH). Eight weeks later, a closed-coil spring appliance was placed between the maxillary incisor and the first molar and then activated with 50 cN of force. During tooth movement, 30 μg/kg of PTH was administered 3 times per week in the PTH group. Tooth movement distances were measured weekly. Five rats in each group were killed after 3 weeks for microcomputerized tomographic analysis, and the remaining 5 rats in each group were killed at an additional 3 weeks after the removal of the appliance to measure relapsed distance.

RESULTS

The OVX group showed significantly greater tooth movement compared to those in the other 2 groups at 2 and 3 weeks (P < .05). The relapse distance and relapse percentage for the OVX group were higher; however, it did not differ significantly from the PTH group. On micro-CT analysis, bone volume/tissue volume ratio and bone mineral density in the PTH group were significantly greater than in the OVX group (P < .05).

CONCLUSIONS

Application of PTH did not promote tooth movement in OVX rat, however, did lead to decrease in relapse tendency. Therefore, the application of PTH during orthodontic treatment of patients with osteoporosis should be carefully considered.

Ascending Facial Necrotizing Fasciitis in a Patient Taking a Bisphosphonate

Facial necrotizing fasciitis (NF) is a rare fulminant infection of the soft and connective tissues that spreads along the fascial planes of the face. Its origins most commonly involve odontogenic infection and it is usually associated with a history of dentoalveolar surgery, such as tooth extraction or implant placement. We present a case of ascending facial NF with odontogenic origin in a patient taking a bisphosphonate.

Association between insulin resistance and periodontitis in Korean adults

OBJECTIVE

Recent studies have proposed an association between periodontitis and metabolic abnormalities. We investigated the association between insulin resistance and periodontitis among Korean adults.

METHODS

A cross-sectional analysis was conducted using the Korea National Health and Nutrition Examination Survey 2008-2010. A total of 16,720 non-diabetic subjects over 18 years old were evaluated (7060 men and 9660 women). Periodontal status was assessed by the Community Periodontal Index. Insulin resistance was measured using the homeostasis model assessment of insulin resistance (HOMA-IR). Participants in the highest and lowest quartile of HOMA-IR were defined as insulin-resistant and insulin-sensitive respectively.

RESULTS

The prevalence of periodontitis increased significantly with higher HOMA-IR quartiles in post-menopausal women (p for linear association = 0.019). Among post-menopausal women, participants in the highest quartile of HOMA-IR were significantly more likely to have periodontitis compared to those in the lowest quartile [adjusted odds ratio (OR), 1.47; 95% confidence interval (CI), 1.07-2.01]. Moreover, obese post-menopausal women showed an increased association between insulin resistance and periodontitis (adjusted OR, 1.92; 95% CI,1.29-2.87). However, this association was not found in men or pre-menopausal women.

CONCLUSIONS

Our results suggest that insulin resistance may be associated with periodontitis, especially when combined with obesity, among post-menopausal women in Korea.

Expression of E-cadherin, P-cadherin and N-cadherin in oral squamous cell carcinoma: correlation with the clinicopathologic features and patient outcome

PURPOSE

Alteration of cadherin expression is associated with the loss of cellular differentiation, the acquisition of an invasive phenotype and a poor prognosis in many types of cancer. This study aimed to evaluate the immunoreactivity of E-, P- and N-cadherins (cad) in oral squamous cell carcinoma and to correlate their expression with clinicopathological features and clinical outcome. The interaction between the cadherins was also investigated.

METHODS

A total of 71 tissue samples were examined by immunohistochemical methods on paraffin sections using specific antibodies.

RESULTS

In the primary lesions and lymph node metastases, the immunoreactivity of E-cad was reduced and P-cad was over-expressed, but the expression of N-cad was negative (p<0.001, 0.01 and 0.05, respectively). The reduced primary E-cad expression was related to the invasion pattern and lymph node metastasis (p=0.046 and 0.037, respectively). However, the expression of cadherins did not appear to differ significantly in relation to the histological grade, invasion, tumour size, stage of oral SCC or tumour recurrence. A much greater reduction in the expression of E-cad was found in the positive N-cadherin group (p=0.008). Nonetheless, cadherin expression was not significantly associated with failure-free survival or overall survival in this experiment subset.

CONCLUSION

The reduced E-cad expression and the aberrant N-cad expression are closely associated with each other in oral cancer cases, and this suggests that cadherin switching from E. cad to N. cad may play a critical role in cancer development and metastasis.