Assessment of alveolar bone mineral density as a predictor of lumbar fracture probability

Sex differences and age-related changes in the mandibular alveolar bone mineral density using a computer-aided measurement system for intraoral radiography

This study aimed to conduct a cross-sectional data analysis of the alveolar bone mineral density (al-BMD) in 225 patients of various ages and different sexes. The al-BMD value in the mandibular incisor region was calculated using a computer-aided measurement system (DentalSCOPE) for intraoral radiography. All participants with intact teeth (101 males and 124 females; age range, 25-89 years) were divided into three age-segregated groups (25-49, 50-74, and > 75 years). Statistical differences were evaluated using the Mann-Whitney U or Kruskal-Wallis test. Males exhibited significantly greater al-BMD than females (p < 0.001). The highest means were observed in the 25-49 age group, regardless of sex (1007.90 mg/cm2 in males, 910.90 mg/cm2 in females). A 9.8% decrease in al-BMD was observed with the increase in age in males (25-49 to 50-74 years; p = 0.004); however, no further changes were seen thereafter. In females, a decreasing trend was seen throughout the lifespan, with values reaching up to 76.0% of the initial peak value (p < 0.001). Similar to other skeletal sites, the alveolar bone exhibits sex differences and undergoes a reduction in BMD via the normal aging process.

Biomechanical analysis of alveolar bones with compromised quality supporting a 4-unit implant bridge; a possible association with implant-related sequestration (IRS)

OBJECTIVES

This study aimed to investigate the strain in the bone surrounding dental implants supporting a 4-unit bridge and assess the role of excessive strain as a possible risk factor for implant related sequestration (IRS) or peri-implant medication-related osteonecrosis of the jaw (PI-MRONJ).

MATERIALS AND METHODS

A 3D-mandibular model was constructed using computed tomography and segmented it into cortical and cancellous bones. The 4-unit implant-supported bridges replacing the mandibular posteriors were constructed, and each featuring two, three, and four implants, respectively. The Young's modulus was assigned based on the quality of the bone. A maximum occlusal force of 200 N was applied to each implant in the axial and in a 30-degree oblique direction.

RESULTS

The maximum principal strain of the fatigue failure range (> 3000 µε) in the bone was analyzed. The volume fraction of fatigue failure was higher in poor-quality bone compared to normal bone and oblique load than in axial load. An increasing number of implants may dissipate excessive strain in poor-quality bones.

CONCLUSIONS

Occlusal force applied to poor-quality bone can result in microdamage. Given that unrepaired microdamage may initiate medication-related osteonecrosis of the jaw, long-term occlusal force on fragile bones might be a risk factor.

CLINICAL RELEVANCE

When planning implant treatment for patients with compromised bone status, clinical modifications such as strategic placement of implants and optimization of restoration morphology should be considered to reduce excessive strain which might be associated with IRS or PI-MRONJ.

Influence of General Mineral Condition on Collagen-Guided Alveolar Crest Augmentation

The local regeneration of bone defects is regulated by general hormone, enzyme, ion, and vitamin levels. General diseases and dysregulation of the human mineral system can impact this process, even in alveolar crest. The aim of this study is to investigate a relation between bone density, measured in two-dimensional X-rays, and general mineral condition of patients. The study included 42 patients on whom tooth extractions were performed. Data were divided into two groups: the region where collagen scaffold (BRM) was used and the reference region of intact normal bone (REF). Two-dimensional intraoral radiographs were taken in all cases just after the surgery (00 M) and 12 months later (12 M). Thyrotropin (TSH), parathormone (PTH), Ca²⁺ in serum, HbA1c, vitamin 25(OH)D₃, and spine densitometry were checked. Digital texture analysis in MaZda 4.6 software was done. Texture Index (TI: BRM 1.66 ± 0.34 in 00 M, 1.51 ± 0.41 in 12 M, and REF 1.72 ± 0.28) and Bone Index (BI: BRM 0.73 ± 0.17 in 00 M, 0.65 ± 0.22 41 in 12 M, and REF 0.80 ± 0.14) were calculated to evaluate bone regeneration process after 12 months of healing (TI (p < 0.05) and BI (p < 0.01) are lower in BRM 12 M than in REF). This showed a relation between BI and TSH (R² = 26%, p < 0.05), as well as a between BI and patient age (R² = 65%, p < 0.001), and a weak relation between TI and TSH level (R² = 10%, p < 0.05). This study proved that a collagen scaffold can be successfully used in alveolar crest regeneration, especially in patients with a high normal level of TSH in the middle-aged population.

Fragility fractures and delayed wound healing after tooth extraction in Japanese older adults

INTRODUCTION

Fragility fractures can cause delayed wound healing after tooth extraction, which contributes to an increased risk of osteomyelitis of the jaw. We evaluated whether a history of fragility fracture was associated with increased risk of delayed wound healing after tooth extraction in older adults in Japan.

MATERIALS AND METHODS

Of 5352 people aged 50-89 years in the 2014 basic resident registry of the town of Obuse, the present study included 376 subjects (190 men and 186 women) who completed a structured questionnaire and measurement of the bone mineral densities (BMDs) of the bilateral femoral neck. Delayed wound healing after tooth extraction was self-reported. Fragility fractures were confirmed via examination of hospital medical records. Logistic regression analyses adjusted for age and gender were used to evaluate association of clinical variables with delayed would healing after tooth extractions. Odds ratios (ORs) and the 95% confidence intervals (CIs) of all possible associated variables for the presence of delayed wound healing were calculated.

RESULTS

Subjects with a history of fragility fractures had a significantly higher risk of delayed wound healing compared with those without previous fragility fractures (OR 2.68; 95% CI 1.11-6.46, p = 0.028). This association still remained after adjusted for all other variables (OR 2.70; 95% CI 1.10-6.60, p = 0.030). Delayed wound healing was not significantly associated with the BMD of the femoral neck.

CONCLUSIONS

History of fragility fracture may be associated with increased risk of delayed wound healing after tooth extraction in Japanese men and women aged 50-89 years.

Changing trabecular patterns in panoramic radiographs of Swedish women during 25 years of follow-up

OBJECTIVES

The radiographic trabecular pattern on dental radiographs may be used to predict fractures. The aim of this study was to analyze longitudinal changes in the mandibles of 145 females between 1980 and 2005.

METHODS

Panoramic radiographs were obtained in 1980 and 2005. On 290 radiographs, regions of interest (ROIs) were selected in the ramus, angle and body. In all ROIs, the orientation was measured in 36 directions with the line frequency deviation method. The effects of ageing were analyzed for the fracture and the non-fracture groups separately.

RESULTS

During the follow-up, 61 females suffered fractures of the hip, wrist, spine, leg or arm. The fracture and non-fracture groups displayed dissimilar age changes in each investigated ROI. All significant changes pertained to increasing values of line frequency deviation. With increasing age, the trabecular network in the mandible lost details and the trabeculae became more aligned in their main direction. In the "ramus", the alignment was to the 110-120˚ axis, parallel to the posterior and anterior ramus border. In the "angle", the alignment was to the 135-150˚ axis, parallel to the oblique line, and in the "body" ROI to the 150-175˚ direction, approximately parallel to the occlusal plane and inferior cortex.

CONCLUSION

Most changes were consistent with the notion that the bone aged less severely in the non-fracture group. In the fracture group, the findings indicate that bone loss leads to redistribution of the remaining bone tissue in such a way that the trabeculae are accentuated perpendicular to the principal loading.

The Implications of Endocrinology in Orthodontics – Literature Review

Endocrinopathies have a variety of orofacial presentations which span from dental malocclusion to facial disfigurement. These characteristics depend on the nature and severity of the condition. An orthodontist should understand the body’s physiological processes to be able to timely determine the optimum intervention and plan treatment stages accordingly in compromised individuals. Communication between the two specialties should be well coordinated and should help facilitate quality health care to the patient. This review was aimed to impart the basic knowledge and the pivotal guidelines for orthodontic management in these conditions. Systemic conditions require multidisciplinary management and the dental team should aim to provide quality oral health care to enhance the overall quality of life and the orthodontist plays a vital role in helping patients achieve physical and psychological health.

Bone marrow mesenchymal stem cell-derived exosomes enhance osteoclastogenesis during alveolar bone deterioration in rats

BMMSC-derived exosomes from rats with bone deterioration increased the osteoclastogenesis of the Raw264.7 cells, which suggests that BMMSC-derived exosomes could accelerate osteoclastogenesis in alveolar bone deterioration.

Bone Density and Dental External Apical Root Resorption

When orthodontic patients desire shorter treatment times with aesthetic results and long-term stability, it is important for the orthodontist to understand the potential limitations and problems that may arise during standard and/or technology-assisted accelerated treatment. Bone density plays an important role in facilitating orthodontic tooth movement (OTM), such that reductions in bone density can significantly increase movement velocity. Lifestyle, genetic background, environmental factors, and disease status all can influence a patients' overall health and bone density. In some individuals, these factors may create specific conditions that influence systemic-wide bone metabolism. Both genetic variation and the onset of a bone-related disease can influence systemic bone density and local bone density, such as observed in the mandible and maxilla. These types of localized density changes can affect the rate of OTM and may also influence the risk of unwanted outcomes, i.e., the occurrence of dental external apical root resorption (EARR).

Oestrogen regulates bone resorption and cytokine production in the maxillae of female mice

Oestrogen plays major role in bone metabolism/remodelling. Despite of well-established effect of oestrogen deficiency on long bones, it remains unclear whether alveolar bone is affected. We aimed to determine the effect of oestrogen-deficiency in the alveolar bone microarchitecture. C57BL6/J and Balb/c mice were ovariectomized and implanted with oil-(OVX) or 17β-estradiol (E2)-containing (OVX+E2) capsules. Ovary-intact mice were used as controls. The dose of E2 replacement was selected based on trophic effects on the uterus and femur bone loss. As determined by maxillary alveolar bone MicroCT analysis, both C57BL6/J and Balb/c OVX mice displayed decreased trabecular thickness, bone density and bone volume, and increased trabecular separation at 15 and 30 days after ovariectomy. These effects were associated with a reduction of trabecular bone percentage and cortical thickness in the femur. A significant loss of alveolar bone crest was also associated with ovariectomy in both mice strains. The E2 replacement fully prevented ovariectomy-induced alterations in the alveolar and femoral bones. Moreover, TNF-α (tumour necrosis factor-α) levels and RANKL/OPG (receptor activator of NF-κB ligand/osteoprotegerin) ratio were increased in the maxilla after OVX, and these responses were also reversed by E2. In conclusion, oestrogen deficiency causes maxillary alveolar bone loss, which is similar to the effects found in the femur. The release of inflammatory molecules like TNF-α, RANKL and OPG is the potential mechanism to the decrease of bone quality and alveolar bone crest.