Alveolar Bone Mineral Research Articles

Dual X-ray absorptiometry for alveolar bone: precision of peri-implant mineral measurements ex vivo.

The precision of measurements of minor mineral changes in alveolar bone mineral content (ABMC) and alveolar bone mineral density (ABMD) on implant surfaces was determined in small regions (0.03 +/- 0.005 cm2) using dual X-ray absorptiometry (DXA). Dog hemimandibles with alveolar processes containing 17 implants were studied ex vivo. The precision was expressed as the coefficient of variation in percent (c.v. %). The ultra-high resolution protocol was applied to the mesial, distal and apical subregions of each implant. The line spacing was 0.0254 cm and the point resolution was 0.0127 cm. The mean c.v. (%) +/- s.d. for the ABMC in the mesial, distal and apical regions were 0.42 +/- 17, 0.47 +/- 0.21 and 0.48 +/- 0.18, respectively. For the ABMD these values were 0.42 +/- 0.16, 0.47 +/- 0.19 and 0.48 +/- 0.16. For each region approximately 68% of the 17 c.v. values were distributed within 1 s.d. from the mean c.v. These results indicate that measurements are highly reproducible (better than 0.48%) and that there are no differences in precision between several peri-implant regions. Changes as small as 0.85% in ABMC and ABMD in small areas adjacent to implant surfaces are measurable with a confidence level of 95%. Therefore the DXA technique will be expedient for our research evaluating the efficacy of the ceramic hydroxyapatite implant releasing agents affecting or inducing alveolar bone- and root cementum-like materials on its surface.

Disturbance of the eruption of the first molar and ankylosis of tooth root by HEBP administration in newly born rat

In this study, we have investigated the effects of HEBP on alveolar bone remodeling and molar tooth development of new born rats especially with regard to the relation of the mineralization rate and tooth eruption. New born rats (3 to 5 days after birth) were injected with 10 mg/kg body weight HEBP subcutaneously every day except Sunday. Mandibles were investigated radiologically and histologically. The mineralization rate of alveolar bone and dentin was assessed by energy-dispersive X-ray (EDX) analyis. Soft X-ray radiography disclosed the failure of the first molar tooth eruption, and histological findings showed ankylosis of alveolar bone and tooth root, and dentin resorption by multinucleated giant cells. The result of EDX analysis revealed hypo-mineralization of alveolar bone and normal mineralization of dentin. These data suggest that preosteoclasts might be recruited at the site of alveolar bone and tooth germ interface but could not differentiate into bone-resorbing mature osteoclasts because of hypo-mineralization of alveolar bone.

Developmental disturbances of the rat molar induced by two diphosphonates.

Very few reports have been published about the effects of diphosphonates on the cells and tissues of developing teeth. The present study was designed to investigate possible morphological changes in ameloblasts and odontoblasts and relate these changes to defects in the enamel surface of erupted teeth. Young rats were injected subcutaneously with single or multiple doses of HEDP or Cl2MDP (10 mg P/kg b.w.). Light microscopic examination of developing maxillary first molars showed that single injections of HEDP or Cl2MDP induced subameloblastic cysts between the secretory ameloblasts and the developing enamel. The ameloblastic lining of the cysts contained numerous calcified deposits. A few days after injection, hypoplasias were seen in the enamel in areas previously occupied by cysts. In the erupted teeth, scanning electron microscopic examination revealed enamel hypoplasias which were mainly localized on the mesial sides of the cusps. In addition to the previously mentioned disturbances, multiple injections resulted in more extensive cysts, some of which contained non-mineralized enamel matrix. Inhibition of the mineralization of dentin and alveolar bone was also noticed.

Correlative transmission and scanning electron microscopy of the initial mineralization of healing alveolar bone in rats.

Primary mineralization in healing sockets after extraction of molar teeth was studied in rats. The observations obtained by scanning electron microscopy were correlated by transmission electron microscopy. The process is characterized by abundance of extracellular matrix vesicles distributed between the forming cells and the calcifying fronts. The occurrence of osmiophilic material and solitary hydroxyapatitte crystals within the vesicles was followed by accumulation of hydroxyapatite crystals, disappearance of the vesicular membrane and formation of calcospherites that conglomerate into calcified fronts. The process described here in bone healing is essentially similar to primary mineralization in other normal and pathological calcified tissues.

Acta Radiologica Official Organ of the Radiological Societies of Denmark, Finland, Norway and Sweden Quantitative Long-Term Determinations of the Alveolar Bone Mineral Mass in Man by125I Absorptiometry I. Accuracy and Precision of the Method

Acta Radiologica Official Organ of the Radiological Societies of Denmark, Finland, Norway and Sweden Quantitative Long-Term Determinations of the Alveolar Bone Mineral Mass in Man by¹²⁵I Absorptiometry I. Accuracy and Precision of the Method

Quantitative long-term determinations of the alveolar bone mineral mass in man by 125-I absorptiometry. II. Following periodontal surgery.

The influence on the alveolar bone mineral mass of two common techniques of periodontal surgery, mucoperiosteal flap operation and gingivectomy, was investigated in patients with periodontal disease. The bone reaction, similar with respect to type of treatment, was characterised by a loss of mineral mass during three to four weeks after surgery. The maximum loss was 0.3 mg - mm-minus 2 on an average (10 to 15 per cent). A remineralization of the alveolar bone followed towards the presurgical level, which was reattained after four to six months.

Effect of extreme calcium deprivation on degree of mineralization of alveolar bone, dentin and enamel in rats

abstract – The effect of an extreme and prolonged calcium‐depriving regimen on the degree of mineralization of alveolar bone, dentin and enamel in adult female rats has been studied by quantitative microradiography. This method is considered to be the method of choice for disclosing differences in V% hydroxyapatite (HA). Despite the calcium‐depriving regimen causing a substantial loss of bone mineral from femur and tibia, as estimated by gravimetric methods, the mineral content of alveolar bone, expressed as V% HA, did not deviate significantly from the normal, indicating that no osteolytic processes had taken place. Neither did the degree of mineralization of the fully formed molar dentin deviate from the normal. However, dentin and enamel formed during the experimental period by the continuously growing incisors disclosed a degree of mineralization which was significantly lower than normal. It was further noticed that the mineral content of the lingual dentin of the incisors, from both experimental and control animals, was significantly lower than the labial dentin.