Implant-supported fixed prosthesis improves nutrient intake in patients with partial edentulous posterior regions

Chronic kidney disease compromises structural and mechanical properties of maxillary cortical bone in a rat model

PURPOSE

This study aimed to investigate the effects of chronic kidney disease (CKD) on the structural and mechanical properties of the maxillary and mandibular cortical bone.

METHODS

The maxillary and mandibular cortical bones from CKD model rats were used in this study. CKD-induced histological, structural, and micro-mechanical alterations were assessed using histological analyses, micro-computed tomography (CT), bone mineral density (BMD) measurements, and nanoindentation tests.

RESULTS

Histological analyses indicated that CKD caused an increase in the number of osteoclasts and a decrease in the number of osteocytes in the maxilla. Micro-CT analysis revealed that CKD induced a void volume/cortical volume (%) increase, which was more remarkable in the maxilla than in the mandible. CKD also significantly decreased the BMD in the maxilla. In the nanoindentation stress-strain curve, the elastic-plastic transition point and loss modulus were lower in the CKD group than that in the control group in the maxilla, suggesting that CKD increased micro fragility of the maxillary bone.

CONCLUSIONS

CKD affected bone turnover in the maxillary cortical bone. Furthermore, the maxillary histological and structural properties were compromised, and micro-mechanical properties, including the elastic-plastic transition point and loss modulus, were altered by CKD.

Xerostomia aggravates ligation-induced peri-implantitis: A preclinical in vivo study

OBJECTIVES

Previous studies have indicated that xerostomia is a critical factor affecting periodontitis; nonetheless, it is controversial whether xerostomia impairs peri-implant tissue. The objective of this experimental study was to evaluate the effect of xerostomia on the peri-implant hard and soft tissues in the rat model.

MATERIALS AND METHODS

Implants were placed in bilateral maxillae of male Wistar rats. The animals underwent submandibular and sublingual gland resection on both sides (DRY group) or sham operation (CTR group). Silk ligatures were placed around one side of abutments, which were randomly selected in each animal. The effects of xerostomia were assessed using micro-CT, histological analysis, real-time PCR, and 16S rRNA-based metagenomic analysis.

RESULTS

Ligation with silk thread caused bone resorption around implants. Although xerostomia itself did not induce bone resorption, it significantly enhanced silk ligature-mediated bone resorption around implants. Histological analysis and real-time PCR indicated that xerostomia induced inflammation and osteoclastogenesis around implants with silk ligatures. Furthermore, it altered the microbiota of the plaque on the silk thread around implants.

CONCLUSION

Xerostomia accelerates mucosal inflammation and osteoclastogenesis, which aggravates bone resorption around implants.

The relationship between masticatory performance and intakes of foods and nutrients in Japanese male workers: A cross-sectional study

BACKGROUND

Although many studies have been conducted on the relationship between masticatory performance and nutrient ingestion in the elderly, few large-scale studies have been carried out using relatively young individuals.

OBJECTIVES

The objective of this study was to clarify the association between the masticatory performance evaluated by the gummy-jelly test, not by visual examination, and nutrient ingestion state based on the brief self-administered diet history questionnaire (BDHQ).

METHODS

This was a cross-sectional survey of 540 male workers. Somatometry, blood pressure measurement, blood test and medical interview were performed as a periodic health check-up. In the dental check-up, an oral examination, gummy-jelly test (glucosensor) and survey of ingested food and nutrients using BDHQ were performed. The participants were classified into two groups with low and normal values of masticatory performance. Participants with a score on the gummy-jelly test below 150 mg/dL or 150 mg/dL or higher were included in the low and normal groups, respectively.

RESULTS

Two hundred and forty-eight participants (45.8%) had low masticatory performance, and 292 (53.2%) had normal masticatory performance. The intakes of some minerals and vitamins, such as calcium, vitamin D, vitamin B₂ , small fish with bones and non-oily fish, were significantly lower in the low masticatory group than in the normal group. In contrast, the intake of sugar for coffee and tea and that of chicken were significantly higher in the low masticatory group than in the normal group.

CONCLUSION

This study suggested that low masticatory performance can affect nutrient intake, which may cause non-communicable diseases.