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Aims: This study evaluated the mechanical properties of mandibular bone tissue retrieved from postmenopausal women under alendronate treatment., Methods: Twenty postmenopausal women were divided into two groups: healthy postmenopausal subjects (control group) and osteoporotic subjects treated with alendronate (alendronate group). Mandibular bone samples were retrieved with a trephine bur at the time of dental implant placement and fixed in 4% formalin. Samples were processed for hard tissue histology, and the bone surface was analyzed for nanohardness measurement. Nanohardness and elastic modulus were evaluated by using a Berkovich tip with elastic modulus of 1.016x106 MPa, Poisson coefficient of 0.3, and a load of 100 mN. Each cycle was configured with a load time of 18 seconds (speed of 1 mN/second), the discharge time of 18 seconds, and a rest time of 5 seconds during indentation at a depth of 10 μm., Results: The control group presented the highest values for nanohardness and elastic modulus (p less than 0.05) in relation to the osteoporotic subjects., Conclusions: Within the limitations of the study, it can be concluded that treatment with alendronate negatively influenced the mechanical properties of mandibular bone in postmenopausal women by reducing bone nanohardness and elastic modulus., Competing Interests: The authors declare no conflicts of interest., (Copyright© by the International Academy of Periodontology.)

Objectives: The aim of this study was to investigate bone turnover alterations after alendronate (ALD) withdrawal and its influence on dental implants osseointegration., Materials and Methods: Seventy female Wistar rats were randomly divided in 2 groups that received on day 0 either placebo (control group-CTL; n = 10) or 1 mg/kg sodium alendronate (ALD; n = 60) once a week for 4 months. At day 120, ALD treatment was suspended for 50 animals. Then, a titanium implant was placed in the left tibia of each rat that were randomly allocated in five subgroups of ten animals each, according to the period of evaluation: day 0 (INT-0), day 7 (INT-7), day 14 (INT-14), day 28 (INT-28), and day 45 (INT-45) after ALD withdrawal. CTL group and a group that received ALD until the end of the experimental period (non-interrupted group-non-INT; n = 10) underwent implant placement on day 120. Animals were euthanized 28 days after implant surgery. Bone mineral density (BMD) of femur and lumbar vertebrae were evaluated by DXA, biochemical markers of bone turnover were analyzed by ELISA, and bone histomorphometry was performed to measure bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO)., Results: All groups receiving ALD showed higher BMD values when compared to CTL group, which were maintained after its withdrawal. Decreased concentrations in all bone turnover markers were observed in the non-INT group, and in the groups in which ALD was discontinued compared to the CTL group. The non-INT group showed lower %BIC and notably changes in bone quality, which was persistent after drug withdrawal., Conclusion: Collectively, the findings of this study demonstrated that ALD therapy decreased bone turnover and impaired bone quality and quantity around dental implants, and that its discontinuation did not reverse these findings., Clinical Relevance: The severe suppression of bone turnover caused by the prolonged use of ALD may alter the capacity of bone tissue to integrate with the implant threads impairing the osseointegration process.

Objectives: This study evaluated the influence of oestrogen deficiency and its therapies on bone tissue around osseointegrated implants., Methods: Implants were placed in 66 female rats tibiae. The animals were assigned into five groups: control (CTL), sham, ovariectomy (OVX), oestrogen (EST), and alendronate (ALE). While CTL was sacrificed 60 days after implant placement, other groups were subjected to ovariectomy or sham surgery according to group and euthanized after 90 days. Blood and urine samples were collected at sacrifice day for osteocalcin (OCN) and deoxypyridinoline (DPD) quantification. Densitometry of femur and lumbar vertebrae was performed in order to evaluate rats' skeletal impairment. Non-decalcified sections were referred to fluorescent and light microscopy for analyses of mineral apposition rate (MAR), eroded and osteoclastic surfaces, bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO)., Results: Results from the OVX group showed significantly lower bone mineral density (BMD), BIC, BAFO, and MAR, while OCN, deoxipiridinoline, eroded surface and ostecoclastic surface were increased compared with the other groups of the study. ALE reduced OCN and DPD concentrations, MAR, osteoclastic and eroded surfaces, and no difference was in BIC and BAFO relative to SHAM. EST and CTL showed similar results to SHAM for measurements., Conclusions: Oestrogen deficiency exerted a negative influence on bone tissue around implants, while oestrogen replacement therapy and alendronate were effective against its effects. Although alendronate therapy maintained the quantity of bone around implants, studies evaluating bone turnover kinetics are warranted., (© 2010 John Wiley & Sons A/S.)

Objective: This study evaluated the influence of estrogen deficiency and its treatment on bone density around integrated implants., Study Design: Implants were placed in female rat tibiae. The animals were assigned to 5 groups: control, sham, ovariectomy, estrogen, and alendronate. The control group was humanely killed to confirm integration of the implant. The others were submitted to ovariectomy or sham surgery. Bone density was measured by digital radiographs at 6 points on sides of the implant., Results: The analysis of radiographic bone density revealed estrogen privation had a negative impact only in the cancellous bone. The estrogen group differed significantly (P < .05) from the ovariectomy and alendronate groups. The alendronate group presented the highest density for all evaluated regions., Conclusion: Ovariectomy caused a decrease in the radiographic bone density in the cancellous region. Estrogen replacement therapy and alendronate were effective treatments in preventing bone mass loss around integrated implants.

Background: This study investigated the influence of estrogen deficiency and its treatment with estrogen and alendronate on the removal torque of osseointegrated titanium implants., Methods: Fifty-eight female Wistar rats received a titanium implant in the tibia metaphysis. After 60 days, which was needed for implant osseointegration, the animals were randomly divided into five groups: control (CTLE; N = 10), sham surgery (SHAM; N = 12), ovariectomy (OVX; N = 12), ovariectomy followed by hormone replacement (EST; N = 12), and ovariectomy followed by treatment with alendronate (ALE; N = 12). The CTLE group was sacrificed to confirm osseointegration, whereas the remaining groups were submitted to sham surgery or ovariectomy according to their designations. After 90 days, these animals were also sacrificed. Densitometry of femur and lumbar vertebrae was performed by dual-energy x-ray absorptiometry (DXA) to confirm systemic impairment of the animals. All implants were subjected to removal torque., Results: Densitometric analysis of the femur and lumbar vertebrae confirmed a systemic impairment of the animals, disclosing lower values of bone mineral density for OVX. Analysis of the removal torque of the implants showed statistically lower values (P <0.05) for the OVX group in relation to the other groups. However, the group treated with alendronate (ALE group) presented significantly higher torque values compared to the others., Conclusion: According to this study, estrogen deficiency was observed to have a negative influence on the removal torque of osseointegrated implants, whereas treatment with alendronate increased the torque needed to remove the implants.