An overview of osteoporosis for the practising prosthodontist

Osteoporosis treatment by mesenchymal stromal/stem cells and their exosomes: Emphasis on signaling pathways and mechanisms

Osteoporosis is the loss of bone density, which is one of the main problems in developed and developing countries and is more common in the elderly. Because this disease is often not diagnosed until a bone fracture, it can become a life-threatening disease and cause hospitalization. With the increase of older people in a population, this disease's personal and social costs increase year by year and affect different communities. Most current treatments focus on pain relief and usually do not lead to bone tissue recovery and regeneration. But today, the use of stem cell therapy is recommended to treat and improve this disease recovery, which helps restore bone tissue by improving the imbalance in the osteoblast-osteoclast axis. Due to mesenchymal stromal/stem cells (MSCs) characteristics and their exosomes, these cells and vesicles are excellent sources for treating and preventing the progression and improvement of osteoporosis. Due to the ability of MSCs to differentiate into different cells and migrate to the site of injury, these cells are used in tissue regenerative medicine. Also, due to their contents, the exosomes of these cells help regenerate and treat various tissue injuries by affecting the injury site's cells. In this article, we attempted to review new studies in which MSCs and their exosomes were used to treat osteoporosis.

Advances in mesenchymal stem cell transplantation for the treatment of osteoporosis

Osteoporosis is a systemic metabolic bone disease with characteristics of bone loss and microstructural degeneration. The personal and societal costs of osteoporosis are increasing year by year as the ageing of population, posing challenges to public health care. Homing disorders, impaired capability of osteogenic differentiation, senescence of mesenchymal stem cells (MSCs), an imbalanced microenvironment, and disordered immunoregulation play important roles during the pathogenesis of osteoporosis. The MSC transplantation promises to increase osteoblast differentiation and block osteoclast activation, and to rebalance bone formation and resorption. Preclinical investigations on MSC transplantation in the osteoporosis treatment provide evidences of enhancing osteogenic differentiation, increasing bone mineral density, and halting the deterioration of osteoporosis. Meanwhile, the latest techniques, such as gene modification, targeted modification and co-transplantation, are promising approaches to enhance the therapeutic effect and efficacy of MSCs. In addition, clinical trials of MSC therapy to treat osteoporosis are underway, which will fill the gap of clinical data. Although MSCs tend to be effective to treat osteoporosis, the urgent issues of safety, transplant efficiency and standardization of the manufacturing process have to be settled. Moreover, a comprehensive evaluation of clinical trials, including safety and efficacy, is still needed as an important basis for clinical translation.

Effect of mucostatic and selective pressure impression techniques on residual ridge resorption in individuals with different bone mineral densities: A prospective clinical pilot study

STATEMENT OF PROBLEM

Although different impression techniques have been advocated for complete denture prosthodontics, objective studies that predict their effect on alveolar bone resorption are lacking.

PURPOSE

The purpose of this prospective clinical pilot study was to objectively evaluate the effect of complete dentures fabricated by different impression techniques on mandibular residual ridge resorption in individuals with different bone mineral density.

MATERIAL AND METHODS

Ninety-six participants with edentulism, selected according to inclusion criteria, underwent bone mineral density assessment and were divided into normal, osteopenic, and osteoporotic groups. Half of the participants in each group were provided with dentures fabricated by selective pressure impression technique (subgroup SIT), and the other half were provided with dentures fabricated by mucostatic impression technique (subgroup MIT). Computed tomographic scans of the mandible were made at denture delivery and 1 year after prosthesis use to assess alveolar bone height and width difference at marked locations at and after denture delivery. The data obtained were analyzed with the Student t test (α=.05).

RESULTS

Significantly less reduction in mandibular ridge height and width was found in the MIT versus the SIT subgroups in both osteopenic and osteoporotic participants (P<.05). No significant subgroup difference was found for normal bone mineral density group, although resorption increased in height and width for the SIT subgroup.

CONCLUSIONS

Mandibular residual ridge resorption was reduced for dentures fabricated using the mucostatic impression technique compared with the selective pressure impression technique in individuals with diminished bone density.

Osteoporosis: Its Prosthodontic Considerations - A Review

Osteoporosis is a disease of bone which is common in middle aged post-menopausal women. The osteoporotic bones will become weak and are prone to fractures. Osteoporosis means "porous bone" is a "silent disease". Healthy bone microscopically appears like a honeycomb but, in osteoporotic patients the spaces are much bigger. The osteoporotic bone will have less density or mass and the structure of bone tissue is abnormal. As the bone becomes less dense, they become weaker and more likely to fracture. Women are four times more likely to develop osteoporosis than men. Oral health maintenance for adults with osteoporosis is important. Bone weakness and loss may also affect the ridges that hold dentures resulting in poor fitting dentures. The patients require new dentures more often than those who have strong, healthy bones. Best way to handle problems is avoid delaying or postponing the dental treatment. Regular dental visits and healthy lifestyle is necessary in strengthening and maintenance of good bone health. Well balanced diet with high amounts of vitamin-D & calcium with regular physical activity is recommended.

The effect of osteoporosis on residual ridge resorption and masticatory performance in denture wearers

AIM

To compare masticatory performance, masticatory efficiency and residual ridge resorption (RRR) in osteoporotic and non-osteoporotic edentulous subjects after rehabilitation with complete dentures.

METHOD

Thirty subjects fulfilling the inclusion criteria were enrolled from the patients visiting the Department of Prosthodontics for complete denture fabrication. Two groups consisting of control subjects (group I; N = 15) and osteoporotic subjects (group II; N = 15) were formed. Complete dentures satisfying certain criteria were fabricated for both groups. Masticatory performance and efficiency were measured 6 months after denture insertion. Areal measurements were taken on lateral cephalograms before and 6 months after denture fabrication. The data were then computed to analyse differences between groups I and II using SPSS statistical software version 15.0.

RESULTS

Six months after denture fabrication, the masticatory performance and efficiency were significantly higher (p < 0.001) for group I, with a significant decrease in maxillary and mandibular sagittal area seen in both groups. The rate of bone loss was more in group II compared with group I.

CONCLUSION

Greater masticatory function was demonstrated by the non-osteoporotic group, and the rate of RRR was more in the osteoporotic group compared with the normal group. In this pilot study, osteoporosis leads to greater RRR, decreased masticatory performance and efficiency in edentulous subjects 6 months after denture insertion. Screening for osteoporosis is suggested as a routine procedure for all edentulous subjects undergoing rehabilitation. Recall check-ups for osteoporotic patients should be more frequent, and these patients may require more frequent denture remakes.

Residual ridge atrophy in complete denture wearers and relationship with densitometric values of a cervical spine: a hierarchical regression analysis

BACKGROUND

The rate of residual ridge atrophy (RRR) and its association with mineral density of other bones have not yet been fully explained.

OBJECTIVE

To measure RRR over a 5-year period in complete denture wearers and relate it to the density of a cervical spine (CSBD).

MATERIALS AND METHODS

Sixty-two patients (different gender, age, body mass index, duration of edentulousness (DE) and different denture-wearing habits) participated. A copper stepwedge was attached to the cassette, and 50 lateral radiograms met the criteria to be included.

RESULTS

A significant decrease in vertical height was observed in all measured sites. The amount of RRR was highest in frontal areas of both jaws and decreased gradually towards lateral regions. Hierarchical regression analysis revealed that the amount of RRR in the maxillary frontal area could be explained up to 48.4% by the variable DE and only up to 6.1% by the CSBD, while gender had almost no influence (1%). Similar results were obtained for the lateral maxillary RRR (33.9%; 7%; 2%), frontal mandibular RRR (40; 8.4; 0.4%) and lateral mandibular RRR (31.5%; 3.4%; 7.7%).

CONCLUSION

Skeletal bone density, reflecting systemic and hereditary factors, is weakly related to RRR (3.4-8.4%).