**6. Bisphosphonate-related osteonecrosis of the jaw**

BPs alter the bone tissue metabolism by inhibiting bone resorption and reducing bone turnover. At the cellular level, BPs affect the recruitment of osteoclasts, their viability, the bioavailability of their progenitors, and their effect on bone. From a molecular point BPs have been proposed to modulate the function of osteoclasts by reacting with a surface receptor or with an intracellular enzyme [93]. BRONJ is defined as an area of exposed bone in the maxillofacial region that does not heal within 8 weeks in a patient who is receiving treatment with a BP. BRONJ develops secondary to the mechanisms of action of BPs in anti-osteoclastic and antiangiogenic

#### **Figure 3.**

*BRONJ in a 63-year-old woman subsequent to extraction of mandibular molar. The patient was on intravenous zoledronate for 1 year (adapted and modified from Anil et al. [83]).*

activities, which alter bone metabolism, inhibit bone resorption and reduce bone turnover. Additional signs and symptoms may include pain, swelling, paresthesia, suppuration, soft tissue ulceration, intra- or extraoral sinus tract formation, tooth loosening, and radiographic variability. These symptoms most commonly occur at sites of previous tooth extractions or other dental surgical interventions but may occur spontaneously. The exact role of BPs remains to be determined, and alterations in bone homeostasis coupled with odontogenic or surgical insult, or both, may be key to the development of osteonecrosis of the jaw [88, 93]. Cases of BRONJ are more common when frequent doses of intravenous BPs are used in treating malignancy than when oral BP regimens are used in treating osteoporosis [94].

The diagnosis of BRONJ is primarily based on the patient's history and the findings of a clinical examination. Most of the time, these patients have necrotic bone exposure ranging from a few millimeters to larger areas and can be asymptomatic for weeks, months, or years (**Figure 3**). The incidence of BRONJ is higher in the mandible than in the maxilla and in areas of thin mucosa overlying bony prominences, such as tori and the mylohyoid ridge. The management of BRONJ mainly comprises pain control measures, antibiotic therapy, mouth rinsing, BP discontinuation, hyperbaric chamber therapy, laser therapy, and surgical debridement [95, 96]. Assessments of markers of bone resorption, such as the serum C-terminal telopeptide of type I collagen; CTx or ITCP) test, can be used to assess the risk of developing BRONJ. Patients with a CTx level lower than 150 pg./mL should consider discontinuation of BP therapy for a period of 4–6 months.

## **7. Conclusion**

Osteoporosis is a common skeletal disorder characterized by reduced bone mass and altered bone architecture, leading to an increase in bone fragility and the risk of fracture. This condition is associated with a decrease in bone quality and quantity,

*Osseointegration of Dental Implants and Osteoporosis DOI: http://dx.doi.org/10.5772/intechopen.100270*

which might affect dental implant osseointegration. The placement of dental implants in patients with osteoporosis is still debated because of the quality of the bone, which is a key factor that determines the success of dental implantation. Although osteoporosis is not considered a risk factor for dental implant failure, the initial implant stability can be influenced by both the local and skeletal bone density, and the healing time is prolonged in osteoporotic patients. While the risk of osteonecrosis of the jaw in patients on BPs is low, patients should be informed of this risk and sign a consent form including this specific point. Based on the available literature, it can be concluded that implants placed in patients with systemic osteoporosis did not present higher failure rates than those placed in patients without osteoporosis.
