Nonrestorative Treatments for Caries: Systematic Review and Network Meta-analysis.

The goal of nonrestorative or non- and microinvasive caries treatment (fluoride- and nonfluoride-based interventions) is to manage the caries disease process at a lesion level and minimize the loss of sound tooth structure. The purpose of this systematic review and network meta-analysis was to summarize the available evidence on nonrestorative treatments for the outcomes of 1) arrest or reversal of noncavitated and cavitated carious lesions on primary and permanent teeth and 2) adverse events. We included parallel and split-mouth randomized controlled trials where patients were followed for any length of time. Studies were identified with MEDLINE and Embase via Ovid, Cochrane CENTRAL, and Cochrane Database of Systematic Reviews. Pairs of reviewers independently conducted the selection of studies, data extraction, risk-of-bias assessments, and assessment of the certainty in the evidence with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Data were synthesized with a random effects model and a frequentist approach. Forty-four trials (48 reports) were eligible, which included 7,378 participants and assessed the effect of 22 interventions in arresting or reversing noncavitated or cavitated carious lesions. Four network meta-analyses suggested that sealants + 5% sodium fluoride (NaF) varnish, resin infiltration + 5% NaF varnish, and 5,000-ppm F (1.1% NaF) toothpaste or gel were the most effective for arresting or reversing noncavitated occlusal, approximal, and noncavitated and cavitated root carious lesions on primary and/or permanent teeth, respectively (low- to moderate-certainty evidence). Study-level data indicated that 5% NaF varnish was the most effective for arresting or reversing noncavitated facial/lingual carious lesions (low certainty) and that 38% silver diamine fluoride solution applied biannually was the most effective for arresting advanced cavitated carious lesions on any coronal surface (moderate to high certainty). Preventing the onset of caries is the ultimate goal of a caries management plan. However, if the disease is present, there is a variety of effective interventions to treat carious lesions nonrestoratively.

The influence of sucralose on bacterial metabolism.

Sucralose (1',4',6' trideoxy-trichloro-galactosucrose) is a nontoxic, intensely sweet sucrose derivative that has been shown to be non-cariogenic in experimental animals. The purpose of this study was to determine whether certain oral bacteria could utilize sucralose. Sucralose, as a sole carbon source, was unable to support growth of ten strains of oral bacteria and dental plaque. When sucrolose was incorporated into a liquid medium containing glucose or sucrose, all organisms tested displayed similar pH falls, compared with controls. The incorporation of 126 mmol/L sucralose into glucose agar medium caused total inhibition of growth of Streptococcus sobrinus 6715-17, Streptococcus sanguis 10904, Streptococcus sanguis Challis, Streptococcus salivarius, and Actinomyces viscosus WVU627. Sucralose had no effect on IPS production. Sucralose was not bound to, nor taken up by, cells. Sucralose inhibited the formation of glucan and fructan polymers in proportion to the sucralose-to-enzyme ratio, but independent of the sucrose concentration in the assay mixture. No radioactive polymer was formed from 14C-U-sucralose added to mixtures containing glucosyltransferase (GTF) or fructosyl-transferase (FTF). Inhibition of GTF and FTF by sucralose was removed following dialysis of the enzyme/sucralose mixture. These results show that sucralose was not utilized by the oral bacteria tested and that the inhibitory effect of sucralose on GTF and FTF was non-competitive and reversible. The results further support the concept that sucralose is non-cariogenic.

The effects of sucralose on coronal and root-surface caries.

Sucralose is an intensely sweet, chlorinated carbohydrate structurally similar to sucrose; thus, its cariogenic potential is of great interest. Four groups of 12 Sprague-Dawley rats were infected with Streptococcus mutans (sobrinus), caged in a König-Höfer programmed feeding machine, and fed diet 2000 or modified diet to contain sucralose at various concentrations instead of sucrose. Rats fed sucralose diet developed significantly fewer lesions than did the rats fed regular diet 2000. Animals fed diet 2000 also harbored more S. mutans (sobrinus) than did the other groups of animals. In a concurrent study, desalivated rats were inoculated with S. mutans (sobrinus) and Actinomyces viscosus. They were fed (ad libitum) either diet 2000 (contains 56% sucrose) or diet 2000 minus sucrose plus 93 mg% sucralose. The severity of caries lesions in the sucralose-fed rats after 35 days was significantly less than those in the sucrose-fed rats. The amount of root exposure was the same in both groups. However, root-surface caries did not develop in the sucralose-fed rats. These results show that sucralose is non-cariogenic in rats.

The effect of desalivation on coronal and root surface caries in rats.

Although the presence of coronal caries is declining in much of the Western Hemisphere, the prevalence of root surface caries is likely to increase as teeth are retained longer than heretofore. At the same time, an increasing number of the population suffer from dry mouth as a result of taking prescription drugs, with an apparent concomitant increased susceptibility to root surface caries. This study attempted to develop an animal model which would aid in the exploration of the effects of desalivation and the development of root surface caries. Animals were desalivated, infected with Actinomyces viscosus and Streptococcus mutans (sobrinus) 6715, and fed a cariogenic diet. Coronal caries developed rapidly in the animals; sufficient disease was present after two weeks to permit evaluation of potential therapeutic agents. Alveolar bone loss and root surface lesions developed in three to four weeks. S. mutans (sobrinus) and A. viscosus established readily in all animals; however, as the investigation progressed, populations of the latter declined, possibly because of the highly acidogenic environment. This model will facilitate investigation of the influence of hyposalivation and help in the exploration of agents to alleviate the adverse effects of salivary gland dysfunction.

The effects of cheese snacks on caries in desalivated rats.

Rats that had had their submandibular/sublingual glands removed surgically, and their parotid ducts tied, developed fewer and less severe caries lesions on coronal and root surfaces when fed cheese snacks in addition to a cariogenic diet than when fed additional cariogenic snacks or no additional snacks. The effects of cheese snacks were particularly dramatic on root-surface caries. These observations may be relevant for elderly humans who are most likely to develop root surface caries. Populations of Streptococcus mutans did not differ among the groups. Actinomyces viscosus was not detected at the end of the experiment in any of the groups. The results of this study demonstrate that cheese exerts a protective effect against coronal and root-surface caries in rats with a severely limited salivary function.

The BioMask for treatment of corneal surface irregularities with excimer laser phototherapeutic keratectomy.

PURPOSE: To assess the characteristics of BioMask as a potential masking agent for use with the excimer laser. METHOD: We addressed ablation rate, smoothness, ease of use, dioptric shift, treatment of standardized irregular topography, and ability of BioMask to induce dioptric change in vivo. RESULTS: BioMask ablates at a rate of 0.28 microm per pulse. The BioMask conforms to the base curve of a contact lens in the excimer blank, eye bank eye, and rabbit eye with a r2 of 0.9982, 0.9844, 0.9858, respectively. We are readily able to create 20 diopters of flattening or steepening (r2 = 0.9944). Standardized irregular topography generation in the rabbit eye and then removal with BioMask was successful. The central corneal topography of the rabbit cornea showed predictable changes with various contact lens base curves with the BioMask (r2 = 0.875). CONCLUSIONS: BioMask has excellent potential as an ablatable mask material in the treatment of superficial corneal scars.

A laser-powered hydrokinetic system for caries removal and cavity preparation.

BACKGROUND: Laser systems have been developed for the cutting of dental hard tissues. The erbium, chromium:yttrium-scandium-gallium-garnet, or Er,Cr:YSGG, laser system used in conjunction with an air-water spray has been shown to be efficacious in vitro for cavity preparation. METHODS: The authors randomly selected subjects for cavity preparation with conventional air turbine/bur dental surgery or an Er,Cr:YSGG laser-powered system using a split-mouth design. They prepared Class I, III and V cavities, placed resin restorations and evaluated subjects on the day of the procedure and 30 days and six months postoperatively for pulp vitality, recurrent caries, pain and discomfort, and restoration retention. Sixty-seven subjects completed the study. RESULTS: There were no statistical differences between the two treatment groups for the parameters measured with one exception; there was a statistically significant decrease in discomfort levels for the laser system at the time of cavity preparation for subjects who declined to receive local anesthetic. CONCLUSIONS: The Er,Cr:YSGG laser system is effective for preparation of Class I, III and V cavities and resin restorations are retained by lased tooth surfaces. CLINICAL IMPLICATIONS: Hard-tissue cutting lasers are being introduced for use in operative dentistry. In this study, an Er,Cr:YSGG laser has been shown to be effective for cavity preparation and restoration replacement.

Injectable biomaterials for adipose tissue engineering.

Adipose tissue engineering has recently gained significant attention from materials scientists as a result of the exponential growth of soft tissue filler procedures being performed within the clinic. While several injectable materials are currently being marketed for filling subcutaneous voids, they often face limited longevity due to rapid resorption. Their inability to encourage natural adipose formation or ingrowth necessitates repeated injections for a prolonged effect and thus classifies them as temporary fillers. As a result, a significant need for injectable materials that not only act as fillers but also promote in vivo adipogenesis is beginning to be realized. This paper will discuss the advantages and disadvantages of commercially available soft tissue fillers. It will then summarize the current state of research using injectable synthetic materials, biopolymers and extracellular matrix-derived materials for adipose tissue engineering. Furthermore, the successful attributes observed across each of these materials will be outlined along with a discussion of the current difficulties and future directions for adipose tissue engineering.

How do serum cobalt and chromium levels change after metal-on-metal hip resurfacing?

We prospectively monitored changes in serum cobalt and chromium levels after a new generation metal-on-metal hip resurfacing and the affect on renal function. Levels were measured using inductively coupled plasma mass spectrometry and atomic absorption spectrometry, preoperatively then sequentially at 3, 6, 9, 12, and 24 months. For serum cobalt, there was an initial increase to a peak level at 6 months, followed by a gradual decline during the next 15 months. A similar trend was observed in serum chromium, although the peak level occurred slightly later, at 9 months. There was no adverse affect on renal function during the 2-year study period. All implants were functioning well, with no radiographic evidence of loosening. These levels will continue to be monitored to establish when minimum metal ion levels are reached.

Production of methyl farnesoate by the mandibular organs of the mud crab, Scylla serrata: validation of a radiochemical assay.

Parameters for the validation of a radiochemical assay to monitor the biosynthesis and release of methyl farnesoate (MF) by the mandibular organs (MO) of the mud crab, Scylla serrata, have been defined. On the basis of HPLC analysis, MF appeared to be the exclusive radiolabeled product of release, using [3H-methyl]methionine as precursor. HPLC of isooctane extracts of medium in which MO had been maintained similarly revealed that MF was the exclusive 3H-product and indicates that the isooctane partition assay can be employed to monitor MF release. The time course of MF biosynthesis and release suggested that the endogenous L-methionine pool is large, because both cumulative release and rate of release increased over an 8-hr incubation but remained constant between 8 and 16 hr. Glandular content of MF did not appear to stabilize until 6-8 hr after the start of the incubation. Cumulative MF release, as a function of glandular content or biosynthesis, increased gradually with time, but even after 16 hr the majority of biosynthesized MF was retained within the MO rather than released. L-Methionine concentration in the incubation medium influenced both MF biosynthesis and release, although the dose dependency was more apparent with biosynthesis. Although it was difficult to associate strictly a level of biosynthesis with L-methionine concentration, low rates of MF biosynthesis were observed at concentrations of less than 25 microM. Because high levels of biosynthesis were observed consistently between 60 and 70 microM L-met, all subsequent incubations employed a concentration of 65 microM. MO of S. serrata show a striking asymmetry in MF biosynthesis and release which is not time dependent. Hence the comparison of right and left glands in assessing the effects of experimental treatments is precluded.

Effect of desalivation and age on susceptibility to infection by Streptococcus sobrinus.

The influence of desalivation and age on susceptibility to infection by Streptococcus sobrinus was studied using 80 Sprague-Dawley female rats weaned at age 21 days. Forty animals (donors) were infected with S. sobrinus 6715 (ATCC 27352), formed into ten groups of 4, fed diet 2000, and offered 10% sucrose water ad libitum. The remaining 40 animals were fed laboratory chow and sterile distilled water until introduced into the experiment. When the animals were aged 25 days, 10 noninfected animals were anesthetized, desalivated, and caged with 10 infected (donor) animals (group I). On day 36 these procedures were repeated on the remaining animals (group II). Infection was checked daily. Animals were regarded as infected when S. sobrinus was detected on 2 consecutive days and confirmed 1 week later. Animals were killed, jaws dissected, and populations of S. sobrinus and total bacterial viable count of each jaw estimated. The average number of days from pairing to detecting infection (2 consecutive days) was as follows: group I (age 25 days): desalivated 5.4 (SD 2.5), intact 8.8 (SD 4.5); group II (age 36 days): desalivated 7.8 (SD 2.9). Only 3 intact animals became infected in group II after a total elapsed time of 21 days. The mean viable counts of S. sobrinus per jaw in group 1 were as follows: desalivated 3.6 x 10(6) (SD 4.1); donor cagemate 13.0 x 10(6) (SD 9.7); intact 0.26 x 10(6) (SD 0.39); donor cagemate 4.5 x 10(6) (SD 4.3). Desalivated animals tended to be more heavily infected than intact animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions of sanguinarine and zinc on oral streptococci and Actinomyces species.

Sanguinaria extract, which contains benzophenanthridine alkaloids, has been used as a folk medicine for many years. Minimum inhibitory and minimum bactericidal concentrations (MIC and MBC values) for sanguinarine were determined for common and etiologically important plaque bacteria. Because the efficacy of sanguinarine is believed to be enhanced by zinc, isobolograms were assessed to determine their mode(s) of interaction. Hydrogen ion concentration influenced the inhibitory activity of both sanguinarine and zinc. For sanguinarine, at the optimum pH (6.5), MIC values were 4 or 8 micrograms/ml for Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguis, Actinomyces viscosus and Actinomyces naeslundii. MIC values were 0.125-0.50 mmol Zn/ml. MBC values ranged from 1 to 8 mmol Zn/ml at pH 5.5. Isobologram data revealed that sanguinarine and zinc interacted synergistically. Viadent oral rinse, which contained 300 micrograms sanguinaria extract/ml and 0.2% zinc chloride (14.9 mmol Zn/l), was inhibitory to all strains tested. MIC values were 1 or 2% (ml Viadent oral rinse/100 ml aqueous solution) for all strains except A. viscosus for which the MIC value was 12% (vol/vol).