Relationship of osteoporosis to excessive residual ridge resorption

Evaluation of Radiomorphometric Indices in Panoramic Radiograph - A Screening Tool

Background : Mandibular cortical indices, like the mandibular cortical index (MCI), panoramic mandibular index (PMI), mental index (MI), antegonial index (AI) and gonial index (GI) have been developed to assess and quantify the quality of mandibular bone mass. Aim and Objectives : The aim of this pilot study was to measure the radiomorphometric indices in a digital panoramic radiograph and find the inter-relationship of the indices with age and sex of the patients. Materials and Method : A total of 23 randomly selected patients were included in the study. Panoramic radiograph of each patient was taken and radiomorphometric indices were determined. Results : There was 69.57% agreement between MI and PMI which was significant. Similarly 78.26% agreement was seen between AI and MI which was significant. In contrast 30.43%, 52.17% and 56.52% agreement was observed while comparing GI with PMI, MI and AI respectively. Conclusion : MCI, PMI, AI and MI can be effectively measured on a panoramic radiograph, hence could be used as a screening tool for determining osteoporosis. All indices have a negative correlation with age and a significant difference between the younger and older age groups. All indices were significantly lower in females when compared to males of the same age group.

Relationship between body mass index and local quality of mandibular bone structure in elderly individuals

BACKGROUND

Human bones decrease in density and increase in porosity beginning at about the third decade of life. The objective of this study was to determine whether mandibular bone mineral density (BMD) and some linear radiomorphometric measurements on dental panoramic radiograph (DPR) are correlated with different categories of body mass index (BMI) in elderly individuals.

METHODS

Cortical width at gonion (GI), at antegonion (AI), and below mental foramen (MI) and the appearance of the cortex of the lower border of the mandible distal to the mental foramina due to resorptive changes (mandibular cortical index [MCI]) were measured bilaterally on the mandible on 136 DPRs of elderly individuals. Using DPRs and copper stepwedge, mandibular BMD was investigated densitometrically. All BMD values were expressed in equivalents of the actual stepwedge thickness. The patients with BMIs from 20 to 25 kg/m(2) were classified as category 1 (the generally accepted range of normal BMI), and the patients with BMIs higher than 25 were classified as category 2 (heavy individuals with a heavy skeleton and a large amount of fat in the body).

RESULTS

The results revealed statistically significant differences in all measured indices between different BMI categories (p <.05 for MI; p <.001 for GI and AI). Statistically significant differences were also found in BMD values between different BMI categories (p <.05); the differences were more pronounced in women. The patients with MCI category 3 had significantly lower BMD values in comparison to MCI category 2 (p <.01). Intraobserver agreement in GI, AI, MI measurement, and MCI assessments was excellent.

CONCLUSIONS

Heavy people have higher BMD and higher values in linear radiomorphometric measurements than lighter people.

Options for tissue engineering to address challenges of the aging skeleton

There will be more than 52 million Americans over the age of 65 by the year 2020 (U.S. Census Bureau). Regenerating form and function to bone defects in an elderly, osteoporotic population of this magnitude will be a daunting challenge. Tissue engineering options must be considered to answer this challenge. Options can include gene transfer technology, stem cell therapy, and recombinant signaling molecules. An additional component will be a carrier that localizes, protects, predictably releases cues and cells, as well as establishes an environment for restoring osseous form and function. The purposes of this article are to present an overview of the bone regenerating decrement affecting osteoporotic, elderly patients and to highlight some tissue engineering options that could offset this decrement.

Toward an understanding of implant occlusion and strain adaptive bone modeling and remodeling

STATEMENT OF PROBLEM

Dental implant failure rates for osseointegration are greater in the highly atro-phic maxilla. Presuming higher failure rates relate to strain-driven adaptation, an enhanced understanding of formative bone response to loading (modeling) and maintenance of an integrated state (remodeling) should improve treatment.

PURPOSE

To understand the role of occlusal loading on long-term osseointegration in areas of compromised cancellous bone, a review of the salient features of adaptive bone modeling and remodeling is presented with an emphasis on cancellous bone responses.

CONCLUSIONS

The ability for dental implants to maintain a long-term stable interface in the maxilla lies in the ability of trabecular bone to maintain adequate local material (strength) and architectural (connectivity) properties. In this discussion, an emphasis has been placed on understanding how trabecular bone can respond to the mastication-induced loading environment on an implant.

Osteoporosis and oral bone loss

This paper is a review of the literature on the possible association between osteoporosis and oral bone loss, with an emphasis on radiological studies. Such an association was first suggested in 1960. Subsequent histomorphometric and microradiographic studies showed that after the age of 50 there was a marked increase in the cortical porosity of the mandible, with this increase being greater in the alveolar bone than the mandibular body; and that with this increase in porosity, there was a concomitant decrease in bone mass, which appeared to be more pronounced in females than in males, with the loss in bone mineral content estimated to be 1.5% per year in females and 0.9% in males. These studies also demonstrated a considerable amount of variation in the amounts of cortical and trabecular bone within and among individuals. Subsequent clinical studies reported associations between the bone densities of jaws and (1) metacarpals, (2) forearm bones, (3) vertebrae and (4) femurs. These studies indicated that women had lower mandibular bone mineral content (BMC) than men and that age-related loss of bone was more pronounced in women after the age of 50 years than in men of the same age, as was the case for the rest of the body. It was suggested that systemic factors responsible for osteoporotic bone loss may combine with local factors (periodontal diseases) to increase rates of periodontal alveolar bone loss. Although not all studies found associations between osteoporosis and oral bone loss, the conclusion of this review is that such an association exists; yet additional longitudinal investigations are needed to confirm this, and before the implications of this association could be fully utilized in clinical dentistry, inexpensive methods must be developed for sensitive and specific measures of oral bone loss.

Prosthetic possibilities using endosseal implants as anchorages--an epidemiological study in 65-year-old subjects

In order to evaluate the possibility of using endosseal implants (ITI Dental Implant System) and implant-retained prostheses for 65-year-old patients from a medium-sized Finnish city, 431 such patients were examined by means of panoramic radiographs. The population represents 61% of the total age group in the city (born in 1923). The possibility to construct a prosthesis, anchored on implants, was evaluated in three different groups. It was shown that in group I (edentulous maxilla and mandible, 256 patients) all male and 97% of female subjects could have been treated with implant-retained over-dentures in the lower jaw. Corresponding figures in the upper jaw were 62% for males and 59% for females. In patients with edentulous maxilla and dentulous or partially edentulous mandible (group II, 84 subjects) implant-retained overdenture in the maxilla could have been possible in 52% of male and 43% of female participants. In subjects with own teeth left in both jaws (group III, 91 participants) some kind of implant-retained bridge or single implants could have been constructed in 70% in maxilla and in 92% in mandible.

Sex-related differences in the bone mineral density of atrophic mandibles

The bone mineral content in a standardized site was measured in 25 edentulous mandibles with dual-photon absorptiometry. The results of the bone mineral content examinations demonstrated a significant difference between the sexes. With advancing age of the subjects, the values measured in the men's mandibles tended to increase slightly, whereas those in the women's mandibles tended to decrease. As a functional adaptation to preserve the stability of the male atrophic mandible, the amount of inner cortical bone is increased. Explanations for this observation are discussed. That the mandibles of men and women change differently with increasing age should be considered in routine examinations, because osteoporosis may be regarded as a cofactor of residual ridge resorption in women.

Sex-related changes in the bone mineral content of atrophic mandibles

In 25 edentulous anatomical mandible specimens (15 female, age range 69-90 years; 10 male, age range 68-88 years), the bone mineral content (BMC) was measured by dual-photon absorptiometry (DPA) and analyzed in a standardized area of the mandibular body. The results of our BMC examinations showed that there was a significant difference (P = 0.05) between the two sexes. Another notable fact was that, with advancing age, the values measured in the male mandibles tended to increase slightly but in a statistically significant way. Those of the female mandibles tended to decrease with age. A possible explanation for this observation may be derived from the fact that a reduction of the mandibular height leads to a reduction of the moment of resistance. As functional adaptation in order to preserve the stability of the atrophic body of the mandible, the amount of inner cortical bone of the male mandibles increases, leading to a reduction of the cancellous portion. In the mandibles of women, postmenopausal osteoporosis seems to prevent an analogous compensation mechanism.

Strategies to affect bone remodeling: osteointegration

Osteointegration was defined as a "direct structural and functional connection between ordered living bone and the surface of a load-carrying implant." Although osteointegration was meant originally to describe a biologic fixation of the titanium dental implants, it is now used to describe the attachment of other materials used for dental and orthopedic applications as well. Analyses of material-bone interface showed that osteointegrated implants can have an intervening fibrous layer or direct bone apposition characterized by bone-bonding depending on the composition and surface properties of the biomaterial. This article reviews biologic (host tissue properties and response), biomechanical, and biomaterial factors affecting osteointegration. Biologic factors include the quality of bone. Biomaterial factors include the effect of material composition on the bone-material interface. Suggested areas for future research include determining the correlation between oral bone status and osteoporosis, the effect of gender, age, and endocrine status (e.g., osteoporosis) on implant success or failure, the effect of calcium phosphate coating composition and crystallinity on in vivo performance of implants, the factors contributing to accelerated osteointegration, and development of osteoinductive implants.

Bone loss in the oral cavity

Bone loss in the oral cavity may occur due to many causes, including infection, systemic or local alterations in the host response, or multifactorial causes. The purpose of this article is to review our present understanding of the major causes of oral bone loss in adults, with special emphasis on two major oral diseases: periodontitis and residual ridge resorption. Periodontitis is characterized by resorption of the alveolar bone as well as loss of the soft tissue attachment to the tooth. Progressive periodontitis will result in continued alveolar bone loss and may result in tooth mobility, abscesses, and ultimately tooth loss. Although the reported prevalence may vary according to the epidemiologic study design, the 1985 National Survey of Oral Health of United States Adults indicated that 94% of female senior citizens examined demonstrated at least one site with at least 2 mm loss of attachment. Resorption of alveolar bone that occurs following tooth extraction is termed residual ridge resorption. In many cases, the denture will loosen because of the inability of the resorbed ridge to stabilize the prosthesis. In the most severe cases, the denture may impinge on the exposed mandibular nerve, resulting in pain or total inability to tolerate the prostheses. Although clear statistics on the prevalence of residual ridge resorption are not available, this boss loss may result in the need for new dentures to replace ill-fitting prostheses.

Inter-relationships between bone mineral content measures. Dual energy radiography (DER) and bitewing radiographs (BWX)

In vitro periodontal alveolar bone mineral content (BMC) measurements obtained with dual-energy radiography (DER) were compared with assessments based on bitewing radiographs (BWX). In addition, in patients, the relationship between bitewing and several postcranial dual-energy-radiographic measures were evaluated. Dual-energy-radiographic and bitewing measurements were made on 2 cadaver mandibles initially and after 2 incremental bone reductions at 4 sites. Rank-order correlations between dual-energy-radiographic and bitewing measures for the 4 sites ranged from 0.7 to 1.00. Bitewing measures indicated true bone loss with a sensitivity of 1.00. For patients, correlations between bitewing measures and dual-energy-radiographic scans suggested the strongest relationships were in the distal sections of the radius and ulna and in the intertrochanteric and Ward's areas of the femur. Correlations, in the 0.5-0.6 range, were not statistically significant (p > 0.05), but were quite robust considering the small sample size and preliminary nature of this investigation. Results suggest that the bitewing measure is sufficiently sensitive to detect clinically meaningful (5% or greater) changes in alveolar BMC and, further, that alveolar bone mineral content may reflect postcranial BMC. The implications of postcranial bone mineral changes being reflected in alveolar bone would enhance both our understanding and treatment of alveolar bone loss. The use of bitewing measures to facilitate identification of patients with postcranial bone loss is discussed.

Variations in adult cortical bone mass as measured by a panoramic mandibular index

This study defines a new radiomorphometric index of mandibular cortical bone mass, the panoramic mandibular index (PMI). Differences in the index in a population of 353 adult subjects, equally divided by sex, age (30 through 79 years), and racial group (black, Hispanic, white), were evaluated. The data were analyzed with respect to side, racial group, sex, age, and combinations of these variables. Blacks were found to have a greater mean PMI than Hispanics or whites, who were statistically similar. Age-related changes comparing younger and older age groups within each sex and racial group indicated a significant decrease in mean PMI with increasing age in black and Hispanic women. The mean PMI in white men increased with advancing age.

Mandibular atrophy and metabolic bone loss. Histomorphometry of iliac crest biopsies in 74 patients

Histomorphometry of iliac crest biopsies of 74 edentulous patients with severe atrophy of the mandible submitted for ridge augmentation, showed a minority of the patients (14%) to have a significant decrease of trabecular bone volume, indicating osteoporosis. On the other hand, osteoid volume, osteoid seam thickness and active resorption surface, parameters for disturbances in mineralization, lack of calcium and hyperfunction of parathyroid glands, were significantly increased by 38%, 88% and 65% of the patients, respectively. These findings were more pronounced in the patients with radiological evidence of metabolic bone loss (38%, Gonion less than 1). It may be concluded that metabolic bone loss, due to a lack of calcium and a subsequent hyperfunction of the parathyroid glands, plays a role in the etiology of severe atrophy of the edentulous mandible. which therefore might be prevented by supplementing with calcium with or without vitamin D.

Calcium metabolism and osteoporotic ridge resorption: a protein connection

The unique interrelationship between excess dietary protein, calcium metabolism, and osteoporosis with its associated ridge resorption has been reviewed. Recommendations for the prevention and management of osteoporosis have been discussed with concern for the calciuretic effect of a high protein diet customarily consumed in American society. Positive calcium balance promoted by the suggested treatment regimen may help to preserve ridge integrity and at the same time prevent the serious debilitating effects of generalized osteoporosis. Further research to evaluate for retardation and possible reversal of osteoporotic ridge resorption as affected by dietary protein intake is warranted.