Bone tissue responses to glass fiber-reinforced composite implants--a histomorphometric study.

OBJECTIVES: The aims of this study were to evaluate bone-to-implant contact (BIC) and the osteoconductive capacity of bioactive fiber-reinforced composite implant (FRC) in vivo. MATERIAL AND METHODS: Threaded sand-blasted FRC implants and threaded FRC implants with bioactive glass (BAG) were fabricated for the study. Titanium implants were used as a reference. Eighteen implants (diameter 4.1 mm, length 10 mm) were implanted in the tibia of six pigs using the press-fit technique. The animals were sacrificed after 4 and 12 weeks. Histomorphometric and scanning electron microscopic (SEM) analyses were performed to characterize BIC. RESULTS: In general, the highest values of BIC were measured in FRC-BAG implants, followed by FRC and Ti implants. At 4 weeks, the BIC was 33% for threaded FRC-BAG, 27% for FRC and 19% for Ti. At 12 weeks, BIC was 47% for threaded FRC-BAG, 40% for FRC and 42% for Ti. Four weeks after implantation, all the implants appeared biologically fixed by a newly formed woven bone arranged in the thin bone trabeculae filling the gap between the implant and the bone of the recipient site. Twelve weeks after implantation, the thickness of the woven bone trabeculae had increased, especially around the FRC-BAG implants. CONCLUSION: Our results suggest that the FRC implant is biocompatible in bone. The biological behavior of FRC was comparable to that of Ti after 4 and 12 weeks of implantation. Furthermore, the addition of BAG to the FRC implant increased peri-implant osteogenesis and bone maturation.

Crosslinked poly(epsilon-caprolactone/D,L-lactide)/bioactive glass composite scaffolds for bone tissue engineering.

A series of elastic polymer and composite scaffolds for bone tissue engineering applications were designed. Two crosslinked copolymer matrices with 90/10 and 30/70 mol % of epsilon-caprolactone (CL) and D,L-lactide (DLLA) were prepared with porosities from 45 to 85 vol % and their mechanical and degradation properties were tested. Corresponding composite scaffolds with 20-50 wt % of particulate bioactive glass (BAG) were also characterized. Compressive modulus of polymer scaffolds ranged from 190+/-10 to 900+/-90 kPa. Lactide rich scaffolds absorbed up to 290 wt % of water in 4 weeks and mainly lost their mechanical properties. Caprolactone rich scaffolds absorbed no more than 110 wt % of water in 12 weeks and kept their mechanical integrity. Polymer and composite scaffolds prepared with P(CL/DLLA 90/10) matrix and 60 vol % porosity were further analyzed in simulated body fluid and in osteoblast culture. Cell growth was compromised inside the 2 mm thick three-dimensional scaffold specimens as a static culture model was used. However, composite scaffolds with BAG showed increased osteoblast adhesion and mineralization when compared to neat polymer scaffolds.

Prevalence of subjective feelings of dry mouth in the elderly.

Dry mouth is a common disorder in elderly individuals. It is not, however, necessarily related to decreased salivary flow rate, since subjective feelings of oral dryness have also been found in those with normal flow rates. The aim of this study was to examine in elderly individuals the prevalence of subjective complaints related to dry mouth, and their association with salivary flow rates and the use of systemic medication. In 1990 and 1991, 368 elderly inhabitants of Helsinki, Finland, had their oral health status examined. In addition to the clinical examination, 341 subjects were interviewed regarding different oral and non-oral complaints related to dry mouth. Findings showed that 46% (n = 158) of the subjects had noticed subjective symptoms of dry mouth. Continuous oral dryness was reported by 12% (n = 40) of the subjects, 6% of the men and 14% of the women (p < 0.05). In these 40, the oral and non-oral symptoms were more frequent in subjects reporting continuous dry mouth compared with controls. Continuous dry mouth was clearly associated with the female gender, with mouth breathing and with the use of systemic medications.

Saliva, salivary micro-organisms, and oral health in the home-dwelling old elderly--a five-year longitudinal study.

High scores of chair-side salivary microbial tests have been found to be related to an increased prevalence and incidence of coronal and root caries. Many elderly face an increased risk of the growth of oral microbes, and previous studies have reported high salivary microbial counts in elderly populations. The aim of this follow-up study was to compare, at five-year intervals, stimulated salivary flow rates with the numbers of selected salivary micro-organisms (mutans streptococci, lactobacilli, and yeasts) in a group of home-dwelling elderly in Helsinki. A further aim was to study the influence of baseline microbial counts on five-year root caries increments and rates of tooth loss. The baseline study population was comprised of 270 subjects who were all participants in the population-based Helsinki Aging Study. Salivary flow rates and microbial conditions were determined as part of their dental examination at the Institute of Dentistry, University of Helsinki, in 1990-1991. Of these subjects, 110 underwent a follow-up examination in 1995-1996. Commercially available kits (Dentocult SM strip mutans for mutans streptococci, Dentocult LB for lactobacilli, and Oricult N for yeasts) were used for the enumeration of micro-organisms, after the collection of paraffin-wax-stimulated whole saliva. The stimulated whole saliva flow rates of the subjects were significantly lower at the follow-up than at baseline (paired t test, difference -0.16 mL/min; p < 0.05), whereas buffer capacity was higher (paired t test, difference 0.19 on a three-unit scale; p < 0.05). Apart from lower salivary lactobacilli counts at follow-up (paired t test, difference -0.44 CFUs/mL of saliva; p < 0.001), no changes were found in salivary microbial levels. Salivary microbial counts were clearly associated with the subjects' dentition types: More denture-wearers had high microbial counts than persons with natural dentitions. None of the salivary factors correlated with the root caries incidence or the number of teeth lost during the five-year follow-up.

Salivary yeasts, saliva, and oral mucosa in the elderly.

Yeasts are commensals in the oral cavity and may not cause disease unless there are predisposing host factors, such as other disease, or when medication is being taken. The elderly are at increased risk of yeast infection. In this paper, prevalence of salivary yeasts in a group of 368 inhabitants of Helsinki aged 76, 81, and 86 years is reported. Salivary yeasts were counted by the Oricult-N dip-slide method, salivary secretion rate and buffering capacity were measured, type of dentition was noted, and signs of yeast infection and the occurrence of subjective symptoms were determined. There was no growth of yeasts in 25% of the subjects. From one to 20 colonies/slide were observed in 21%, 21-50 colonies in 21%, and over 50 colonies (a high count) in 33%. Subjects with low salivary flow rates and low buffering capacities had significantly higher yeast counts than did subjects with normal salivary flow rates and buffering capacities. High yeast counts were found in 19% of subjects with natural teeth. The corresponding percentages in those wearing partial or complete dentures were 32 and 41, respectively. High salivary yeast counts were associated with oral mucosal lesions but not with subjective complaints of oral symptoms.

Association between salivary flow rate and the use of systemic medication among 76-, 81-, and 86-year-old inhabitants in Helsinki, Finland.

The aim of this study was to examine salivary flow rate and its association with the use of medication in a representative sample of 76-, 81-, and 86-year-old subjects, totaling 368. In this study, 23% (n = 80) of the subjects were unmedicated. From one to three daily medications were used by 47% (n = 168) and more than four medications by 30% (n = 104). The most commonly used medications were nitrates, digitalis or anti-arrhythmic drugs (47.7%), analgesics and antipyretics (32.6%), and diuretics (29.5%). The mean number used daily was significantly higher in 86-year-olds than in the two younger age groups (p < 0.01). No significant differences in this respect were found between genders. Among the unmedicated subjects, 76-year-olds had significantly higher stimulated salivary flow rates than did the 81-year-olds (p < 0.05). Unmedicated women showed significantly lower unstimulated (p < 0.01) and stimulated flow rates than did men (p < 0.05). Stimulated salivary flow rate was also significantly higher in the 76-year-old medicated subjects than in the medicated 86-year-old subjects (p < 0.05). No statistically significant differences were found in unstimulated salivary flow rates among the three age groups. Medicated women showed significantly lower unstimulated salivary flow rates than men (p < 0.001), although the difference in stimulated saliva flow was not significant. A statistically significant difference in unstimulated and stimulated salivary flow rates was found between unmedicated persons and those who took from four to six, or more than seven, prescribed medications daily.

Xerostomia and hyposalivation: causes, consequences and treatment in the elderly.

Xerostomia and salivary gland hypofunction (SGH) are prevalent in elderly populations, causing much discomfort and even difficulties in eating. SGH also increases the occurrence and severity of oral diseases and makes the patient susceptible to candidiasis. The principal causes of SGH and xerostomia are systemic diseases and drugs used daily. The diagnosis of SGH and xerostomia is based on simple methods, of which measuring both unstimulated and stimulated salivary flow rate is the most important. Treatment calls for proper management of underlying disease, avoidance of all unnecessary medications, and topical remedies such as artificial saliva substitutes. However, good hydration is essential in the elderly with SGH and xerostomia, and water is the drink of choice. In extremely difficult cases, for instance in patients receiving radiotherapy for cancer of the head and neck regions, parasympathomimetic drugs may be administered if no contraindications exist.

Maxillary overdentures retained by splinted and unsplinted implants: a retrospective study.

The purpose of this retrospective study was to evaluate the clinical performance of and patients' satisfaction with maxillary overdentures retained by splinted and unsplinted implants. Patients who had been treated with maxillary implant-retained overdentures because of functional problems with conventional complete dentures were identified and invited to participate in the study. A total of 16 patients fulfilled the enrollment criteria and agreed to participate. Eleven patients were treated with bar-retained overdentures with 3 to 6 clips (mean follow-up 32 months), and 5 patients wore overdentures retained by 2 to 6 ball attachments (mean follow-up 54 months). All subjects were satisfied with their prostheses, and most subjects experienced improvement in their oral function after treatment with implant-retained overdentures. At the time of clinical examination, 92% (n = 77) of the 84 implants placed were functioning satisfactorily. The cumulative survival rate for the implants after 72 months was 90%. Loss of bone support correlated with peri-implant probing depth (r = 0.29; P < .02). No differences in mean bone loss between the subjects with ball-retained or bar-retained overdentures were found. The presence of plaque or peri-implant bleeding was not associated with the type of attachment.

Periodontal health status and treatment needs among the elderly.

The numbers of dentate elderly are growing rapidly in all industrialized countries, and epidemiological information about their oral health is urgently needed. Our study is part of the population-based Helsinki Ageing Study (HAS), and this paper describes the periodontal health status as well as the need for periodontal treatment among the dentate elderly born in 1904, 1909, and 1914 and living in January, 1989, in Helsinki, Finland (n = 175). The dental examinations were carried out during 1990 and 1991 at the Institute of Dentistry, University of Helsinki, Finland. The subjects' periodontal health was recorded by the CPITN (Community Periodontal Index of Treatment Needs) method. The mean number of remaining teeth was 15.1 among men and 14.0 among women, with the mean number of remaining sextants 3.7 and 3.5, respectively. Healthy periodontal tissues (CPI = 0) were found in 7% of the subjects. Bleeding on probing (CPI = 1) was recorded in 6%, and calculus and/or overhanging margins of restorations (CPI = 2) in 41% of the subjects, as the worst finding. Altogether, 46% of the subjects had deep periodontal pockets, 35% with at least one 4- to 5-mm pocket (CPI = 3), and 11% with at least one > or = 6-mm pocket (CPI = 4). Overall, 93% of the subjects required oral hygiene instruction, 87% scaling and root planing, and 11% complex periodontal treatment. The periodontal treatment need was significantly higher in men than in women; however, no significant differences were observed among the three age cohorts. The need for complex periodontal treatment was unexpectedly low, probably explained by the fact that there were many missing teeth, especially molars, perhaps lost due to poor periodontal health.

Oral health in the elderly with non-insulin-dependent diabetes mellitus.

The purpose of this study was to examine salivary flow rates and selected oral health parameters in 12 patients (aged 76-86 years) with non-insulin-dependent diabetes mellitus (NIDDM) and also in 20 subjects (aged 76-86 years) with NIDDM and cardiovascular diseases (CVD) and to compare them with 32 healthy controls matched for age and gender. Unstimulated salivary flow rates were lower in both groups of NIDDM patients than in the controls, although the differences were not statistically significant. Subjective oral dryness and other oral and non-oral symptoms were more frequently reported by the patients with NIDDM + CVD; however, the differences were usually non-significant. Root-surface caries was more frequently detected in the subjects with NIDDM only, although the difference among groups was not statistically significant. Periodontal treatment need, according to CPITN values, was more frequent in the subjects with NIDDM only, compared with controls or those with NIDDM + CVD, although the differences were again not statistically significant. There were no statistically significant differences in the oral health parameters of the subjects with NIDDM or NIDDM + CVD compared with those of their age- and sex-matched healthy controls.

Osseointegration of fiber-reinforced composite implants: histological and ultrastructural observations.

OBJECTIVES: The aim of this study was to evaluate the bone tissue response to fiber-reinforced composite (FRC) in comparison with titanium (Ti) implants after 12 weeks of implantation in cancellous bone using histomorphometric and ultrastructural analysis. MATERIALS AND METHODS: Thirty grit-blasted cylindrical FRC implants with BisGMA-TEGDMA polymer matrix were fabricated and divided into three groups: (1) 60s light-cured FRC (FRC-L group), (2) 24h polymerized FRC (FRC group), and (3) bioactive glass FRC (FRC-BAG group). Titanium implants were used as a control group. The surface analyses were performed with scanning electron microscopy and 3D SEM. The bone-implant contact (BIC) and bone area (BA) were determined using histomorphometry and SEM. Transmission electron microscopy (TEM) was performed on Focused Ion Beam prepared samples of the intact bone-implant interface. RESULTS: The FRC, FRC-BAG and Ti implants were integrated into host bone. In contrast, FRC-L implants had a consistent fibrous capsule around the circumference of the entire implant separating the implant from direct bone contact. The highest values of BIC were obtained with FRC-BAG (58±11%) and Ti implants (54±13%), followed by FRC implants (48±10%), but no significant differences in BIC or BA were observed (p=0.07, p=0.06, respectively). TEM images showed a direct contact between nanocrystalline hydroxyapatite of bone and both FRC and FRC-BAG surfaces. CONCLUSION: Fiber-reinforced composite implants are capable of establishing a close bone contact comparable with the osseointegration of titanium implants having similar surface roughness.

Prepolymerized vs. in situ-polymerized fiber-reinforced composite implants--a pilot study.

The aim of this study was to investigate bone response to bioactive fiber-reinforced composite (FRC) implants under two polymerization conditions. Glass-fiber-dimethacrylate composite was tested as prepolymerized cylinder-shaped FRC implants and as cylindrical FRC implants polymerized in situ with blue light transmitted and scattered by the glass fibers. Ten FRC implants (6 prepolymerized and 4 in situ-polymerized implants) were placed in the right tibias of 3 pigs by means of a press-fit technique. After 12 weeks, light microscopy revealed only mild foreign-body reaction, with no accumulation of inflammatory cells on both the prepolymerized and the in situ-polymerized implants. The prepolymerized implants appeared to be fully integrated, whereas the in situ-polymerized implants were almost completely surrounded by a fibrous capsule. The present study suggests that in situ polymerization of FRC implants results in fibrous capsule formation and prevents integration with bone.

Adhesion and proliferation of human fibroblasts on sol-gel coated titania.

The objective of this study was to evaluate growth and attachment of human gingival fibroblasts on nonresorbable sol-gel-derived nanoporous titania (TiO2) coated discs and noncoated commercially pure titania (cpTi) discs in vitro. The strength of attachment was evaluated using serial trypsinization. The number of cells detached from TiO2-substrates was 30% +/- 3%, whereas those detached from the cpTi was 58% +/- 4% indicating a stronger cell attachment on the coated surfaces. In scanning electron microscopy (SEM) images fewer cells, with more rounded shape, were seen with cpTi than with TiO2 after the detachment assay. Fibroblasts grew more efficiently on TiO2 than on cpTi substrates, showing significantly higher cell activities at all times. In transmission electron microscopy (TEM), a continuous layer of two to three cells thick covered the coated and noncoated discs after 7 days of culture. The plasma membrane of cells in contact with the coating was in close opposition and the cytoplasm was ultrastructurally similar to the cells grown on noncoated discs with well-preserved organelles. In conclusion, we demonstrated that the sol-gel-derived TiO2 coatings can facilitate cell growth and attachment of human gingival fibroblasts on titanium in vitro. This in vitro study is in line with our previous in vivo observations of improved soft tissue attachment of TiO2 coatings in comparison with cpTi.

Soft tissue attachment on sol-gel-treated titanium implants in vivo.

This study was designed to examine the attachment and reactions of soft tissues to sol-gel-derived TiO2 coatings. In the first experiment, TiO2 coated and uncoated titanium cylinders were placed subcutaneously into the backs of rats for 3, 11 and 90 days. Tissue response and implant surfaces were characterized with routine light microscopy and scanning electron microscopic (SEM) analysis. In the second experiment, TiO2-coated and uncoated discs were implanted subcutaneously into the backs of rats for 14 and 21 days. The discs were pulled out from the implantation sites with a mechanical testing device using a constant speed of 5 mm/min. Rupture force was registered, after which the discs were assigned for SEM and transmission electron microscopic (TEM) analysis. All the coated implants showed immediate contact with the surrounding soft tissues without a clear connective tissue capsule. Significantly better soft tissue response was measured for all the coated compared to the uncoated cylinders (p<0.01). Higher rupture forces were measured for all coated discs, although the differences were not statistically significant. An immediate and tight connection between connective tissue fibroblasts and coatings was noticed in TEM analysis. Our study indicates that TiO2 coatings improve soft tissue attachment on a titanium surface.

Level of education and incidence of caries in the elderly: a 5-year follow-up study.

OBJECTIVE: This study aimed to examine the possible association between level of education and 5-year caries increment in the elderly inhabitants of Helsinki. BACKGROUND: Low salivary flow and high numbers of salivary microorganisms are associated with the presence of caries, but cannot predict the increment in caries in the elderly. MATERIALS AND METHODS: This study group was derived from a population-based Helsinki Aging Study, which consisted of a random sample of elderly born in 1904, 1909 and 1914. The 71 dentate elderly who underwent clinical oral examinations at baseline (1990-91) and 5 years later (1995-96) were included in the study group. Decayed, Missing or Filled Tooth (DMFT) and Root Caries Index (RCI) indexes were used to study subjects' caries experience. Data on subjects' education came from questionnaire studies. The subjects were divided into four groups according to their level of education and occupation. Bivariate and multivariate analyses were used to evaluate relationships between subjects' caries experience and level of education. RESULTS: At baseline the elderly with high level of education had more teeth and more root surfaces at risk than those with low level of education. Number of teeth decreased (-1.085, p < 0.0001), while both DMFT (1.164, p < 0.0001) and RCI (0.081, p < 0.0001) indices increased during follow-up. The increments in DMFT and RCI were not directly associated with the level of education. Multivariate analysis in which subjects' gender, number of teeth, level of education, frequency of eating and frequency of brushing were taken into consideration, showed no significant association with caries increment. CONCLUSIONS: Within the limitations of this study it can be concluded that the level of education of the elderly is not directly associated with the increment in caries.

Mutans streptococci and lactobacilli in the elderly.

The prevalence of salivary mutans streptococci and lactobacilli, salivary flow rate, and the type of dentition were studied in connection with a medical survey of 76-, 81-, and 86-yr-old inhabitants of Helsinki living at home. High bacterial counts were associated with low salivary flow rates. High counts of mutans streptococci (> 10(6) CFU/ml) were found in 68% of wearers of full dentures, as compared with 53% of subjects having natural teeth. High counts of lactobacilli (< 10(6) CFU/ml) were found in 44% of subjects having removable partial dentures and in 39% of subjects having natural teeth. The bacterial counts correlated neither with medicines taken daily nor with diseases among this population.

Oral mucosal lesions and oral hygiene habits in the home-living elderly.

A large epidemiological health investigation, the Helsinki Ageing Study (HAS), was performed in 1989-1991 in Helsinki, Finland. We report here the prevalence of oral mucosal lesions in 338 76-, 81- and 86-year-old home-living elderly people, who completed the oral health investigation at the Institute of Dentistry, University of Helsinki. One or more lesions were found in 128 subjects (38%). Fifty-one per cent of the edentulous complete-denture wearers and 31% of the elderly with some natural teeth had mucosal lesions. The most common finding was inflammation under the denture, which occurred alone or combined with other lesions in 25% of the denture wearers. The three most common mucosal changes not related to denture wearing were coated changes of the tongue (7%), angular cheilitis (6%) and varicose veins under the tongue (4%). No differences were found in the number of mucosal lesions among the three age groups. Angular cheilitis and inflammation under removable dentures were more frequent in women than in men. However, no other differences were found in the presence of mucosal lesions between sexes. The total number of mucosal lesions correlated positively with the number of medications used daily. Ninety-six per cent of the subjects with complete dentures, and 98% of those with some natural teeth reported cleaning their dentures at least once a day. Of the denture wearers, 88% reported cleaning their oral mucosa also, as part of their oral hygiene routine. The presence of mucosal lesions was related to self-reported cleaning of the denture-bearing mucosa. However, no association was observed between cleaning frequency and presence of mucosal changes.

Antimicrobial factors, sialic acid, and protein concentration in whole saliva of the elderly.

Concentrations of salivary antimicrobial factors are well documented in children and young adults, but little information is available on such defense factors in healthy elderly persons. We determined the levels of total IgA, total IgG, lysozyme, lactoferrin, myeloperoxidase, salivary peroxidase, amylase, sialic acid, and total protein in a group of 71 subjects aged 76, 81, and 86 yr, as well as their correlations to paraffin-wax-stimulated salivary flow rate. Participants were either unmedicated (n = 67) or using medicines with no oral significance (n = 4). Statistically significant negative correlations existed between flow rate and total IgA, lysozyme, lactoferrin, sialic acid, and total protein. Concentrations of sialic acid and salivary peroxidase were highest in the oldest age group. Total IgA concentration was higher in women than in men, although men showed higher concentrations of sialic acid and higher sialic acid/total protein ratios. Subjects with poor gingival health had higher concentrations of total protein than did those with no need for periodontal treatment. Edentulous subjects with complete dentures showed significantly lower concentrations of IgG, lactoferrin, and myeloperoxidase than did dentate subjects. Our results suggest that, when compared with data from previous studies, concentrations of salivary antimicrobial agents do not decline with age in unmedicated elderly people. However, defense factors which are derived also from gingival crevicular fluid are decreased in the absence of teeth.

A 5-year follow-up study on the prosthetic rehabilitation of the elderly in Helsinki, Finland.

In 1990, 364 elderly (76-86 years) inhabitants of Helsinki, Finland, attended a dental and oral examination study that was conducted as part of the Helsinki Aging Study. In spring 1996, these subjects were recalled for a 5-year follow-up. Between the baseline and follow-up examinations, 114 (31%) subjects had deceased (86 women and 28 men), whereas 134 had either moved, were too ill, or refused to participate in the follow-up. Follow-up examination was conducted for 113 subjects (79 women and 34 men), with the participating rate being 46%. Five subjects became edentulous during the follow-up. Of the subjects, 61% had 1-32 teeth at follow-up. In these subjects, the mean number of teeth decreased from 14.9 (+/-8.3) to 13.5 (+/-8.6) (P < 0.0001). Prosthetic status changed in 40% of the elderly dentate people: 25% received new prostheses whereas 15% lost prostheses that were not replaced. New fixed partial dentures were made in five maxillae and in nine mandibles during the follow-up. Acrylic removable partial dentures (ARPD) were most frequently used: 35% of dentate subjects had an ARPD. Subjects with removable prostheses had higher levels of salivary microbes and higher root caries incidence than those with natural teeth. Furthermore, the presence of removable prostheses at baseline, together with the male gender, was clearly associated with tooth loss during follow-up. This study indicates that fixed rather than removable prostheses should be used in elderly patients. The need for a removable denture ought to be carefully considered.

Radiographic findings, ridge resorption, and subjective complaints of complete denture patients.

To evaluate the relationship between the complaints of complete denture wearers and alveolar bone resorption as well as the location of mental foramina, 96 patients were interviewed. All subjects had received new dentures at the University of Iowa between August 1985 and July 1990. Panoramic radiographs had been made for all the subjects before dentures were fabricated. The amount of estimated ridge resorption correlated significantly with the number of years females had been edentulous, but no correlation was found in males. The location of the mental foramen in relationship to the crest of residual ridge correlated negatively with the number of years both genders were edentulous. Subjective need for dental treatment, as expressed by "sore gums" or poor or fair chewing ability, were the most frequent complaints among the subjects. These complaints were more often recorded with the subjects who had lost more than 50% of their estimated original ridge height than with those with less than 50% resorption, but this difference was not significant.