**7. Conclusions and perspectives**

Chronic periodontitis and osteoporosis are two chronic diseases, with inflammatory etiopathogenesis, whose statistical characteristics are constantly growing worldwide. Studies focused on the association of these diseases in the same subjects are few and with discordant results. These may be due to the variability of the inclusion/exclusion criteria, the research methodology, as well as the small groups of subjects included.

The research supports the role that a routine operation performed in the dental office - panoramic radiography - could play in detecting undiagnosed cases of osteoporosis, given the local changes that occur in such patients. Signs of periodontal tissue destruction are also reflected radiologically, where the thickness of the mandibular cortex and the morphological appearance of the cortex (presence of erosions) have been shown to be closely correlated with the value of the densitometric T Score. Therefore, orthopantomography, a common procedure in the dental office, could be an effective and less expensive method of screening for osteoporosis, with a significant role for the dentist in this procedure.

Despite advances in research methodology and laboratory tests, in order to identify the factors associated with chronic periodontal disease, it is still unclear how to predict the progression of periodontal disease. Extensive research has been done in the area of host biochemical response markers in periodontal disease. It is unlikely that a unitary biomarker will be able to meet the criteria for estimating future destruction from periodontal disease.

Patients with periodontal disease with osteoporosis had higher levels of TNFα, IL-1α, IL-1β, IL-6 and RANKL in the crevicular fluid, compared to systemically healthy patients. Also, cytokine values were positively correlated with periodontal parameters. Therefore, it can be stated that these patients are prone to excessive production of this type of cytokine which also activates B cells and promotes B cell activity in periodontal inflammatory sites, aggravating the evolution of periodontal disease.

The conventional systemic hormone replacement therapy was associated with lower indices of gingival inflammation, such as a reduced gingival bleeding index in subjects who followed hormone replacement therapy when compared to the subjects without HRT [30]. The risk of tooth loss was reduced in the group with HRT, when compared to patients without HRT and, more importantly, the number of present teeth is directly proportional to the duration of the substitution therapy [30]. The diagnosis of periodontal disease was more common in patients without hormone replacement therapy compared to those with HRT. We can conclude that HRT generates a positive effect on periodontal tissues, an effect that is all the better highlighted as hormone replacement therapy has a longer duration; still, this benefit needs to be carefully assessed and compared to the potential risks of such therapy [30]. These aspects bring in a new sphere the ways of complex and interdisciplinary therapeutic approach of patients with osteoporosis and chronic periodontitis.

We also proposed a unique analysis in the context of the association of the two diseases - periodontal disease and osteoporosis - of the effects generated by a deputy form of periodontal therapy, extremely topical, that of modulation therapy by chemotherapeutic agents of the host's inflammatory response. We demonstrated in the study that adjunctive therapy with sub-antimicrobial doses of doxycycline (administration of 20 mg twice daily, 3 months), in combination with classical therapy, generated significant clinical improvements in patients with periodontal disease and osteoporosis - maintained during the study and that could pre-meet the need for surgery. We also demonstrated that sites with relatively small depths (0-3 mm) in the modulation therapy group showed a slight gain in attachment, while these sites in the control group showed a slight loss of attachment. This supports the efficacy of host response modulation therapy by administering sub-antimicrobial doses of doxycycline. Taken together, the data presented should inspire further research, providing epigenetic responses in periodontics, and using this information to develop future therapies.

The set of studies carried out supports in a complex way the importance of the bidirectionality of the periodontal disease - osteoporosis relationship, offering new information and protocols to approach patients, with certain value both for the medical community and, especially, for the entity that is at the centre of its concern - the patient per se.

Studies have shed new light on the link between periodontal disease (particularly in its chronic form) and osteoporosis. The data obtained show observations of a clinical and paraclinical nature, which aim to expand the knowledge related to this complex association, with practical applicability, which supports the concept of interdisciplinary approach to the patient.

Periodontal tissue damage, clinically detectable by measurements of periodontal parameters (probing depth, loss of clinical attachment, probing bleeding), is more severe in patients with osteoporosis than in systemically healthy patients. Research has shown that osteoporosis systemically creates favourable circumstances for the evolution of periodontal disease, but it is also significantly associated with local determinants and factors.

### **Conflict of interest**

The authors declare no conflict of interest.

*The Role of Osteoporosis as a Systemic Risk Factor for Periodontal Disease DOI: http://dx.doi.org/10.5772/intechopen.96800*
