Association between dietary hardness score and activities of daily living among individuals aged 90 years.

OBJECTIVES: With the rapidly aging world population, Japan has many older people with difficulties in maintaining oral health. This study aimed to investigate the relationship between dietary hardness score and performance of activities of daily living (ADL) of 90-year-old individuals in rural areas of Japan. MATERIAL AND METHODS: A total of 236 individuals (64 men and 172 women) aged 90 years in Mitsugi town, Hiroshima, Japan, were included. Assessment of oral status and survey of ADL were performed. The association of ADL with dietary hardness score and the number of remaining teeth was determined. RESULTS: The mean dietary hardness score was 8.3 ± 2.6. Eighty individuals showed independence in ADL, whereas 156 individuals showed dependence. Logistic regression analysis, adjusted for potential confounding factors, showed that dietary hardness score was associated with ADL status but not the number of remaining teeth. CONCLUSION: Our findings suggest that a low dietary hardness score is associated with dependence on ADL in 90-year-old individuals.

Detection of synthetic RGDS(PO3H2)PA peptide adsorption using a titanium surface plasmon resonance biosensor.

The purpose of this study was to measure the time-dependent chemical interaction between synthetic RGDS(PO(3)H(2))PA (P-RGD) peptide and titanium surfaces using a titanium surface plasmon resonance (SPR) biosensor and to determine the degree of peptide immobilization on the surfaces. An SPR instrument for 'single-spot' analysis was used for nanometer-scale detection of biomolecular adsorption using a He-Ne laser light according to Knoll's method. The oxidized titanium surface was etched when exposed to H(3)PO(4) solutions with a pH of 2.0 or below. The amount of P-RGD adsorbed at pH 1.9 was approximately 3.6 times as much as that at pH 3.0 (P < 0.05). P-RGD naturally adsorbed on the oxidized titanium surface as a consequence of the bonding and dissociation mechanism of the phosphate functional group. Furthermore, the control of pH played a very important role in the interaction between P-RGD and the surface. These findings show that pH control may promote progressive binding of biomolecules with the phosphate functional group to the titanium surface.

Bone turnover markers to assess jawbone quality prior to dental implant treatment: a case-control study.

BACKGROUND: Bone quality is as important as bone mineral density in terms of bone strength. Bone turnover markers (BTMs) are clinical indicators of bone quality. In implant dentistry, bone quality is considered equivalent to bone density on radiographic assessments. The purpose of this study was to determine whether the BTM values are reflected in jawbone condition by evaluating the relationship at baseline and during follow-up in patients with prosthodontic implants. Computed tomography (CT) scans were obtained and BTM (osteocalcin, bone-specific alkaline phosphatase, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen, and crosslinked N-telopeptide of type I collagen) levels in blood samples were measured in partially edentulous eighteen patients before implant surgery. During the follow-up observation after implant surgery, marginal bone loss (MBL) was measured on dental radiography. We investigated the relationship between the presence of BTM abnormalities and radiographic bone density. RESULTS: More women than men had abnormal BTM values. Bone turnover was accelerated in the group of women with abnormal BTM values. The density of cancellous bone at the implant placement site was significantly lower in the patients with abnormally high BTM values than in their counterparts with BTM values in the normal range. CONCLUSIONS: Female patients who undergo implant treatments may have reduced bone quality; evaluations of bone strength will require assessments of both BTMs and the density of cancellous bone.

Chemical interaction between titanium implant surface and amino acids.

The purpose of this study was to investigate the chemical interaction between titanium implant surface and amino acids. Pure titanium disks were pretreated with 10 N HCl and ultrapure water at room temperature for 30 minutes each. Disks were then modified with one of the three amino acids--L-aspartic acid, L-serine, or L-threonine--at 37 degrees C for 12 hours. Modification with oxalic acid was used as a control. By means of X-ray photoelectron spectroscopy (XPS), amino acid powders and the modified surfaces without or with ultrasonic water rinsing were chemically analyzed. It was revealed that the N 1s peak which originated from amino acids was not or hardly detected in the wide scan spectra of amino acid-modified surfaces. Moreover, the COO- peak which originated from oxalic acid could hardly be detected in the narrow scan spectrum of the C is region of oxalic acid-modified surface with ultrasonic water rinsing. Based on the results of this study, it was concluded that amino acids could not chemically bond to the titanium surface.

New surface modification of titanium implant with phospho-amino acid.

The purpose of this study was to investigate a new biochemical surface modification technique for titanium implants using phospho-amino acid. Pure titanium disks were pretreated with 10 N HCl and ultrapure water at room temperature for 30 minutes respectively. Then these disks were modified with either L-threonine (Thr) or O-phospho-L-threonine (P-Thr) at 37 degrees C for 12 hours. X-ray photoelectron spectroscopy (XPS) chemically analyzed the modified surfaces. It was revealed that the N 1s peak which originated from Thr was not detected in the wide-scan spectrum of Thr-modified surface, whereas three peaks of N 1s, P 2s, and P 2p which originated from P-Thr were detected in the wide-scan spectrum of P-Thr-modified surface. Moreover, the P 2p peak of P-Thr which reacted with the surface significantly shifted to a lower binding energy (p < 0.05). Based on the results of this study, it was concluded that P-Thr chemically bonded to the titanium surface treated with HCl.

[Reconstruction of bilateral occlusal-supporting area with removable partial dentures: a case report].

PATIENT: The patient (57-years-old female) suffered from severe chronic periodontitis in the maxillary and mandibular molar regions. After extraction of these teeth, treatment dentures were immediately placed in the maxilla and mandible to restore the occlusal-supporting area. Final denture treatment was done by adjusting the provisional dentures according to the patient's concern. Good prognosis was obtained during 9 years. DISCUSSION: To restore bilateral occlusal-supporting areas, treatment dentures reduced the loss of remaining teeth. CONCLUSION: Treatment dentures can stabilize the occlusal relationship immediately after loss of occlusal-supporting area, and may also contribute the patient's acceptance of and satisfaction with the final prostheses.

Bioactive surface modification of hydroxyapatite.

The purpose of this study was to establish an acid-etching procedure for altering the Ca/P ratio of the nanostructured surface of hydroxyapatite (HAP) by using surface chemical and morphological analyses (XPS, XRD, SEM, surface roughness, and wettability) and to evaluate the in vitro response of osteoblast-like cells (MC3T3-E1 cells) to the modified surfaces. This study utilized HAP and HAP treated with 10%, 20%, 30%, 40%, 50%, or 60% phosphoric acid solution for 10 minutes at 25°C, followed by rinsing 3 times with ultrapure water. The 30% phosphoric acid etching process that provided a Ca/P ratio of 1.50, without destruction of the grain boundary of HAP, was selected as a surface-modification procedure. Additionally, HAP treated by the 30% phosphoric acid etching process was stored under dry conditions at 25°C for 12 hours, and the Ca/P ratio approximated to 1.00 accidentally. The initial adhesion, proliferation, and differentiation (alkaline phosphatase (ALP) activity and relative mRNA level for ALP) of MC3T3-E1 cells on the modified surfaces were significantly promoted (P < 0.05 and 0.01). These findings show that the 30% phosphoric acid etching process for the nanostructured HAP surface can alter the Ca/P ratio effectively and may accelerate the initial adhesion, proliferation, and differentiation of MC3T3-E1 cells.

Real time assessment of surface interactions with a titanium passivation layer by surface plasmon resonance.

Due to the high corrosion resistance and strength to density ratio titanium is widely used in industry, and also in a gamut of medical applications. Here we report for the first time on our development of a titanium passivation layer sensor that makes use of surface plasmon resonance (SPR). The deposited titanium metal layer on the sensor was passivated in air, similarly to titanium medical devices. Our "Ti-SPR sensor" enables analysis of biomolecule interactions with the passivated surface of titanium in real time. As a proof of concept, corrosion of a titanium passivation layer exposed to acid was monitored in real time. The Ti-SPR sensor can also accurately measure the time-dependence of protein adsorption onto the titanium passivation layer at sub-nanogram per square millimeter accuracy. Besides such SPR analyses, SPR imaging (SPRI) enables real time assessment of chemical surface processes that occur simultaneously at "multiple independent spots" on the Ti-SPR sensor, such as acid corrosion or adhesion of cells. Our Ti-SPR sensor will therefore be very useful to study titanium corrosion phenomena and biomolecular titanium-surface interactions with application in a broad range of industrial and biomedical fields.

Preoperative computed tomography-derived bone densities in hounsfield units at implant sites acquired primary stability.

The purpose of this study was to evaluate preoperative CT-derived bone densities in Hounsfield units (HU) at implant sites that acquired primary stability, and to compare these values to the optimal bone densities proposed in the literature. Fifty-one patients, 18 males (37 implant sites) and 33 females (67 implant sites) between 2003 and 2010 were assessed. CT data for different jaw sections, regions, and operating procedures were compared using the Kruskal-Wallis test and Scheffe's test for multiple comparisons (P < 0.05). The mean bone density in the maxilla was significantly lower than that in the mandible (P < 0.05); the mean bone densities in the 4 jaw regions decreased in the following order: anterior mandible > anterior maxilla > posterior mandible > posterior maxilla. The bone densities assessed by HU fell into the range of optimal bone densities associated with acquired primary implant stability proposed in the literature.

A proposed index for residual periodontal ligament support.

An index was developed to estimate the residual periodontal ligament support for individual teeth during treatment planning for partially edentulous patients. The Residual Periodontal Ligament Index (rPLI) was derived from a formula that calculates the remaining area of periodontal attachment and the Normal Periodontal Ligament Index (nPLI). To illustrate the applicability of the rPLI, the total nPLI scores of the remaining teeth corresponding to Eichner subclasses of partial edentulism were charted by assessing the average occlusal support numerically. The rPLI is proposed to be a possible suitable tool for epidemiologic research on the progression of tooth loss and the survival rate of prostheses.

Degree of immobilization of synthetic RGDS(PO(3)H(2))PA peptides on titanium surfaces.

The purpose of this study was to characterize the chemical interaction between titanium surfaces and the peptide RGDS(PO(3)H(2))PA (P-RGD) synthesized from RGD peptide (RGD) and o-phospho-L-serine (P-Ser), and to determine the degree of peptide immobilization on the titanium surface. X-ray photoelectron spectroscopy showed that the adsorption amount of RGD was significantly smaller than those of P-Ser and P-RGD (p<0.05). Furthermore, although it appeared that P-RGD bonded to the surface, ultrasonic rinsing with water caused it to dissociate, releasing RGD and leaving only S(PO(3)H(2))PA bonded to the surface. These findings show that although it remains difficult to obtain a stable P-RGD layer, the phosphate functional group greatly improves immobilization of the molecule on titanium surfaces.

Influence of mental status on removable prosthesis compliance in institutionalized elderly persons.

PURPOSE: It is well-recognized that many institutionalized elderly persons with dementia do not wear dentures. The objective of this study was to evaluate the current status of denture use among elderly patients with dementia, in association with degree of mental impairment, to provide information relating to a decision-making process for optimal denture treatment. MATERIALS AND METHODS: From August 2001 to December 2002, 101 hospitalized elderly persons in a geriatric hospital dental clinic received removable denture treatment by two certified prosthodontists. Prior to denture treatment, patient mental status was evaluated using the Mini Mental Status Examination (MMSE). Basic activities of daily living, including mobility, feeding, toilet use, dressing, and bathing, were also evaluated. Denture acceptance was determined 6 months after denture delivery. RESULTS: Eight patients were excluded; 73 patients had accepted their dentures and 20 had not 6 months after denture delivery. The mean MMSE score for patients who did not accept denture delivery (11.7+/-7.0) was significantly lower than that of those who did accept and wear their dentures (16.0+/-6.8). CONCLUSION: The cognitive status of institutionalized elderly persons with dementia should be a criterion for clinical decision making relating to denture treatment.