Improvement of Sleep Disturbance and Neurocognitive Function after Parathyroidectomy in Patients with Primary Hyperparathyroidism

OBJECTIVE

To investigate the frequency of the nontraditional symptoms of sleep disturbance and impaired cognitive functioning in patients with primary hyper-parathyroidism (PHPT) and to assess changes in such patients after parathyroidectomy.

METHODS

In this study, we used formal neurocognitive assessment of patients undergoing parathyroidectomy for PHPT. The Brief Sleep Disturbance Inventory assessed sleep disturbance, and Stroop tests evaluated for cognitive impairment. Study patients underwent preoperative and postoperative neurocognitive testing.

RESULTS

Fifty-five patients underwent neurocognitive evaluation; the 43 women and 12 men had a mean age of 63 years. Sleep disturbance was assessed in all 55 patients, whereas evaluation for cognitive impairment was performed in 47. Sleep disturbance was identified preoperatively in 24 (44%) of the 55 patients. This disorder affected 17 (31%) of 55 patients postoperatively (P<0.01). Impaired executive functioning was found at baseline in 6 (13%) of 47 patients and decreased to 1 (2%) of 47 post-operatively (P<0.01), whereas impaired cognitive processing speed was detected in 12 (26%) of 47 patients at baseline and decreased to 3 (6%) of 47 after parathyroidectomy (P<0.01). Eight patients did not meet the National Institutes of Health consensus statement criteria for parathyroidectomy; 4 of these patients had preoperative impairment of sleep or cognitive functioning, 3 of whom showed improvement postoperatively.

CONCLUSION

Sleep disturbance and neurocognitive impairment occur in patients with PHPT, and these disorders improve after parathyroidectomy. Further objective evaluation of nontraditional symptoms in patients diagnosed as having PHPT is warranted.

Effect of an alcohol-free, 1% chlorhexidine gel as an adjunct to a fluoridated dentifrice using an intraoral crown model

BACKGROUND/AIMS

The use of chlorhexidine as a topically applied oral antiseptic is well documented; however, clinical studies examining the effects of chlorhexidine gel on in situ dental caries are limited. This study utilized an in situ caries model and a modified crossover design to examine whether the addition of a biweekly topical, alcohol-free, 1% chlorhexidine digluconate gel to a daily fluoridated dentifrice inhibited artificial caries in dental tissues better than the fluoridated dentifrice alone when compared to a nonfluoridated placebo dentifrice.

METHODS

Thirty patients were recruited based on their need for a mandibular, full crown. Artificial caries lesions were created in extracted human teeth and enamel and root tissue sections 100 mum in thickness were characterized using polarized light microscopy. The sections were fixed in the crown and placed on the prepared tooth. The participants were assigned a placebo toothpaste, a toothpaste with 1,100 ppm F or a 1,100 ppm F toothpaste followed by 1 ml of 1% chlorhexidine gel at day 1 and day 14 (chlorhexidine+). Patients were instructed to brush twice daily for 4 weeks. Following each round, the sections in the crown were replaced with new sections. The sections were recharacterized and the mean changes were compared using ANOVA at alpha = 0.05.

RESULTS

The chlorhexidine + Fdentifrice and the F dentifrice alone significantly reduced lesion area in enamel tissue when compared to the placebo dentifrice. Both treatments also inhibited lesion progression and initiation in root tissue better than control in this model system. Although the chlorhexidine+ group enhanced remineralization and inhibited lesion progression better than the F(-) dentifrice alone for all outcomes measured, the differences were not significant.

CONCLUSIONS

The chlorhexidine, in conjunction with a fluoride dentifrice, was no more effective than the fluoride dentifrice alone. Further study is needed before this 1% alcohol-free chlorhexidine gel should be recommended as an adjunct to a fluoride dentifrice in the treatment of dental caries.

A PILOT STUDY OF NEUROCOGNITIVE FUNCTION IN PATIENTS WITH ONE TO THREE NEW BRAIN METASTASES INITIALLY TREATED WITH STEREOTACTIC RADIOSURGERY ALONE

OBJECTIVE

Whether to administer or omit adjuvant whole-brain radiation therapy in conjunction with stereotactic radiosurgery (SRS) in the initial management of patients with one to three newly diagnosed brain metastases is the subject of debate. This report provides data from a pilot study in which neurocognitive function (NCF) was prospectively measured for patients with one to three newly diagnosed brain metastases treated with initial SRS alone.

METHODS

Fifteen patients were prospectively treated with initial SRS alone. Assessment of NCF and magnetic resonance imaging scans were performed.

RESULTS

At baseline, 67% of the patients had impairment on one or more tests of NCF. The domains most frequently impaired at baseline were executive function, motor dexterity, and learning/memory with an incidence of 50, 40, and 27% respectively. Brain metastasis volume (.3 cm3) measured at the time of initial SRS treatment was associated with worse performance on a measure of attention (P &lt; 0.05). At 1 month, declines in the learning/memory and motor dexterity domains were most common. In a subgroup of five patients still alive 200 days after enrollment, four patients (80%) demonstrated stable or improved learning/memory, three (60%) demonstrated stable or improved executive function, and three (60%) demonstrated stable or improved motor dexterity relative to their baseline evaluation.

CONCLUSION

Although two-thirds of the brain metastasis patients had impaired NCF at baseline, the majority of five long-term survivors had stable or improved NCF performance across executive function, learning/memory, and motor dexterity.

Chemotherapy and Cognition: Effects, Potential Mechanisms, and Management

The development of novel chemotherapeutic agents and advances in treatment technique have improved survival for patients diagnosed with some forms of cancer, but treatments are not always site specific and may place normal tissues at risk. The central nervous system (CNS) is susceptible to treatment effects and complaints of memory loss and generalized cognitive decline are common among cancer patients. Despite the frequency of subjective patient complaints, studies evaluating the cognitive abilities of patients have inconsistently reported chemotherapy-related declines. On careful review of the literature, discrepant findings across studies (some documenting chemotherapy-related cognitive declines and others failing to detect such changes) may be attributed to differences in methodology. Most studies have been retrospective in design, omit pretreatment assessment of function, use small or heterogeneous samples, use inappropriate measures to assess cognition, and fail to incorporate control subjects. Though rare to date, prospective, randomized, longitudinal studies that incorporate pretreatment comprehensive neuropsychological assessment are necessary to define the severity and pattern of treatment-related change. Building on a foundation of solid science, future studies may identify subgroups of patients susceptible to significant chemotherapy-related cognitive decline. Once these groups are identified and the mechanisms underlying the decline are elucidated, attention may be turned to the development of treatments that may optimize cognitive function and improve patient quality of life.

The effects of child formula toothpastes on enamel caries using two in vitro pH-cycling models

AIMS/OBJECTIVES

To compare, using two pH-cycling models, the de/remineralisation effects of children's toothpastes on primary teeth.

DESIGN

In vitro single-section and pH-cycling models.

METHODS

Primary teeth were placed in demineralising solution for 96 hours to produce artificial carious lesions 60-100 microm deep. They were cut into 100 microm thick sections and assigned to 6 groups. Sections in Groups A and D were exposed to a non-fluoridated toothpaste, those in Groups B and E to half-pea-sized (0.16g) and those in Groups C and F to pea-sized portions (0.32g) of a 500ppm F toothpaste. pH-cycling Model I (Groups A, B, C), without added fluoride, ran for 7 days, while Model II (Groups D, E, F), with 0.25ppm F, ran for 10 days.

OUTCOME MEASUREMENTS

Lesions were evaluated using polarised light microscopy and microradiography.

RESULTS

Lesions in Groups B and E progressed by 64% and 61%, respectively, while those in Groups C and F progressed by only 19% and 23% respectively.

CONCLUSIONS

Both 10-day and 7-day pH-cycling models were suitable for studying carious lesion progression in primary teeth (the demineralising and remineralising solutions of the 10-day cycling model contained 0.25ppm F). A pea-sized portion (0.32g) of 500ppm F toothpaste slowed down the demineralisation progression better than a half-pea-sized portion.

'Chemobrain' in breast carcinoma?: a prologue

BACKGROUND

Chemotherapy-induced cognitive dysfunction in patients with breast carcinoma has been described previously. However, those studies only assessed patients' postchemotherapy cognitive functioning and were not able to determine the relation between cognitive function and other treatments, such as surgery and radiotherapy, that often precede systemic chemotherapy.

METHODS

Eighty-four women with breast carcinoma underwent a comprehensive neuropsychologic evaluation before receiving adjuvant therapy for nonmetastatic primary breast carcinoma.

RESULTS

Before the start of systemic therapy, 35% of women in the current cohort exhibited cognitive impairment. Verbal learning (18%) and memory function (25%) were impaired significantly more frequently relative to normative expectations. Although the impairments were not significant in the women who were examined, nonverbal memory (17%), psychomotor processing speed and attention (13%), confrontational naming (13%), visuoconstruction (13%), and upper-extremity fine motor dexterity (12%) were impaired more frequently than was expected. Affective distress was related significantly to cognitive impairment (Pearson chi-square = 9.90; P = 0.002). Given the conservative statistical approach employed, extent of surgery, hormone replacement therapy history, and current menopausal status failed to achieve statistical significance, but these variables did exhibit provocative trends with respect to cognitive impairment.

CONCLUSIONS

Cognitive impairment frequently is observed before the administration of systemic chemotherapy. Thus, investigations purporting to measure chemotherapy-induced cognitive dysfunction must employ study designs that incorporate prechemotherapy baseline assessments to accurately detect changes in cognitive function that are attributable to chemotherapy.

Neuropsychological dysfunction associated with cancer and cancer therapies: a conceptual review of an emerging target

Neuropsychological dysfunction associated with cancer and cancer treatment is a growing concern. Methodological limitations permeate the corpus of research in this area and have limited our understanding of the multifactorial nature of this process. The following review provides a summary of the current state of knowledge and highlights future directions.

The cognitive sequelae of standard-dose adjuvant chemotherapy in women with breast carcinoma: results of a prospective, randomized, longitudinal trial

BACKGROUND

Retrospective trials have reported that chemotherapy-induced cognitive dysfunction was experienced by a subset of patients with breast carcinoma. However, recent evidence indicated that a subset also exhibited impaired cognitive function at baseline, before the start of chemotherapy. A prospective, longitudinal trial that incorporates baseline neuropsychologic evaluations is necessary to determine to what extent cognitive dysfunction is attributable to chemotherapy in this population.

METHODS

Eighteen women with breast carcinoma underwent a comprehensive neuropsychologic evaluation before treatment and at short-term and long-term intervals after chemotherapy. The incidence, nature, severity, and chronicity of cognitive dysfunction developing in patients with breast carcinoma treated with a standard dose of adjuvant chemotherapy were assessed.

RESULTS

Before the start of systemic therapy, 33% of women in the current cohort exhibited cognitive impairment. At the short-term postchemotherapy time point, 61% of the cohort exhibited a decline relative to baseline in 1 or more domains of cognitive functioning and reported greater difficulty in maintaining their ability to work. The most common domains of cognitive dysfunction were related to attention, learning, and processing speed. At the long-term postchemotherapy time point, approximately 50% of patients who experienced declines in cognitive function demonstrated improvement, whereas 50% remained stable. Self-reported ability to perform work-related activities also improved over this interval. Neither impairment at baseline nor subsequent treatment-related cognitive decline exhibited any statistically significant correlation with affective well-being or with demographic or clinical characteristics.

CONCLUSIONS

The current study is the first longitudinal trial to report evidence of an association between cognitive dysfunction and chemotherapy in a subgroup of women with nonmetastatic breast carcinoma. The importance of using prospective research designs, appropriate cognitive measures, and statistical methods to evaluate subgroup effects was discussed. Identification of mechanisms associated with cognitive dysfunction and of risk factors contributing to subgroup vulnerability is necessary.

Relationship Between Neuropsychological Test Performance and Productivity at 1-Year Following Traumatic Brain Injury

While there has been strong evidence for the ability of neuropsychological performance at resolution of posttraumatic amnesia to predict later productivity, there has been less conclusive evidence for the relationship of neuropsychological test scores to concurrent productivity status. The purpose of the current study was to evaluate the relationship of neuropsychological test performance at 1 year post-injury to productivity assessed at the same time point. Participants were 518 persons with medically documented TBI who were enrolled in the TBI Model Systems Research and Demonstration Project. Stepwise logistic regression was utilized to determine the contributions of neuropsychological test scores to productivity after accounting for demographic characteristics, injury severity, and pre-injury productivity. Missing neuropsychological test scores were accounted for in the model. Variables that remained in the model and accounted for a significant proportion of the variance included age, duration of impaired consciousness, pre-injury productivity, and scores on measures of GOAT, Logical Memory II, and Trail Making Test, part B. The results indicate that neuropsychological test performance provides important information regarding the ability of persons with injury to return to productive activities. The results also indicate that inability to complete neuropsychological tests at 1 year post-injury is associated with non-productive activity.

Effect of fluoridated milk on progression of root surface lesions in vitro under pH cycling conditions

The aim of this study was to assess the effect of milk with 0, 2.5 or 5 ppm F on progression and remineralization of caries-like root surface lesions using a pH cycling model. The root surface lesions were created utilizing a partially saturated lactic acid buffer at pH 4.6. Longitudinal sections were cut through the lesion and analyzed using polarized light microscopy (PLM) and microradiography (MRG). The sections were then coated with an acid resistant varnish, except the outer natural surface that would be exposed to water, milk or fluoridated milk and cycled in a de- and remineralizing system for 2 weeks. The lesions were characterized again by PLM and MRG after treatment. A significant reduction in lesion progression was found by PLM and MRG after treatment with either non-fluoridated or fluoridated milk when compared to the control group. Using quantitative MRG, mineral change and distribution in the lesions were recorded. A possible protective effect of fluoridated milk on root surface caries was supported by a reduction in the progression of the lesions and an increase in the mineral within the lesion.

Effect of smear layer on root demineralization adjacent to resin-modified glass ionomer

The cariostatic effect of resin-modified glass ionomer (RMGI) on secondary root caries is well-documented. However, this beneficial effect may be dependent upon the mode of cavity surface treatment. To investigate this relationship, we studied 4 cavity surface treatments prior to the placement of RMGI: no treatment (None), polyacrylic acid (PAA), phosphoric acid (H(3)PO(4)), and Scotchbond Multi-Purpose adhesive (SMP) as a control. Specimens were aged for two weeks in synthetic saliva, thermocycled, and subjected to an artificial caries challenge (pH 4.4). Polarized light microscopy (PLM) and microradiography (MRG) showed significantly less demineralization with the H(3)PO(4) cavity surface treatment as revealed by ANOVA and Tukey's multiple comparisons (p < or = 0.05). Dentin fluoride profiles determined by electron probe microanalysis (EPMA) supported PLM and MRG findings. It may be concluded that removal of the smear layer with phosphoric acid provides significantly enhanced resistance to secondary root caries formation adjacent to RMGI restorations.

In situ evaluation of sodium hexametaphosphate-containing dentifrices

The purpose of this investigator-blinded, five-treatment, crossover human intraoral study was to evaluate the effects of two experimental dentifrice formulations containing either stannous fluoride (SnF(2)) or sodium fluoride (NaF) packaged with sodium hexametaphosphate in a dual-phase delivery system on demineralization-remineralization using an in situ model system. The experimental dentifrice formulations' ability to alter demineralization-remineralization was compared to a series of three controls: SnF(2)-positive control, NaF-positive control and no-fluoride placebo-negative control. The single-section crown model, developed at the University of Iowa, was used to assess the fluoride efficacy of two experimental products versus the placebo containing no fluoride and positive controls. The results of the current in situ study suggest a clinical level of anticaries activity for the experimental SnF(2) and NaF dentifrice formulations that was as good as either of the positive controls, when evaluated using polarized light microscopy. This supports the conclusion that the use of the sodium hexametaphosphate ingredient does not interfere with the normal fluoride activity of these toothpastes. In addition, the experimental SnF(2) product was numerically better than both the NaF and placebo controls at preventing demineralization of sound root surfaces.

In vitro evaluation of fluoride-releasing restorative materials for sealing the root canals of overdenture abutments

PURPOSE

The purpose of this study was to evaluate the ability of newer fluoride-releasing restorative materials to protect the root surface from acid attack.

MATERIALS AND METHODS

The materials used were glass-ionomer cement (GIC), resin-modified glass-ionomer cement (RM-GIC), and a compomer (Comp). A composite resin (CR) was used as the control. The restored teeth were stored in deionized, distilled water for 14 days and subjected to 300 thermocycles (55 degrees C and 5 degrees C). The teeth were cycled in a demineralizing solution (pH 5.0 or 4.0) for 6 hours and in a remineralizing solution (pH 7.0) for 17 hours for 10 days. The depths of lesions created by acid challenge were measured at the interface of the tooth and the restorative material and then at a distance of 50, 100, and 300 microns from the tooth-restoration margin using polarized light microscopy and contact microradiography.

RESULTS

At pH 4.0, there was significant difference in the depth at the interface between the tooth and the restorative material (P < .001). The GIC and RM-GIC were protective, and the lesion depths were significantly shallower than for Comp or CR. The protective effect varied depending on the distance from the interface of the tooth and the restorative material. At pH 5.0, the GIC and RM-GIC had no lesions at the interface, while the Comp and the CR had lesions (P < .001).

CONCLUSION

Fluoride-releasing glass-ionomer cement seems to be an appropriate material to seal the root canals of overdenture abutments, because it has an inhibiting effect on demineralization at the cavity wall in vitro.

Patterns of fluoride intake from birth to 36 months

OBJECTIVES

Dental fluorosis prevalence has increased in the United States, Canada, and other nations due to the widespread availability of fluoride in many forms, with fluoride ingestion during the first three years of life appearing most critical in fluorosis etiology. With few contemporary studies of fluoride ingestion in this age group, the purpose of this paper is to describe patterns of estimated fluoride ingestion from birth to 36 months of age from water, dentifrice, and dietary fluoride supplements and combined.

METHODS

Repeated responses to separate series of questions about water intake, use of fluoride dentifrice, and use of fluoride supplements were collected by questionnaire as part of the longitudinal Iowa Fluoride Study and used to estimate fluoride intake. Estimated intake is reported by source and combined at different ages. Effects of subject age and other covariates on fluoride intake were assessed using regression methods appropriate for the analysis of correlated data.

RESULTS

For most children, water fluoride intake was the predominant source, especially through age 12 months. Combined daily fluoride intake increased through 9 months, was lower at 12 and 16 months, and increased again thereafter. Mean intake per unit body weight (bw) was about 0.075 mg F/kg bw through 3 months of age, 0.06 mg F/kg bw at 6 and 9 months, 0.035 mg F/kg bw at 12 and 16 months, and 0.043 mg F/kg bw from 20-36 months. Depending on the threshold chosen (e.g., 0.05 or 0.07 mg F/kg bw), variable percentages of the children exceeded the levels, with percentages greatest during the first 9 months. Regression analyses showed fluoride intake (mg F/kg bw) from 1.5-9 months to decrease with increasing child's age, mother's age, and mother's education, with a complex three-way interaction among these factors. From 12-20 months, fluoride intake increased with increasing child age and decreased with increasing mother's age. No statistically significant relationships were found for fluoride intake from 24-36 months.

CONCLUSIONS

There is considerable variation in fluoride intake across ages and among individuals. Longitudinal studies may be necessary to fully understand the relationships between fluoride ingestion over time and development of fluorosis.

Laser-matrix-fluoride effects on enamel demineralization

Laser and fluoride have been shown to inhibit enamel demineralization. However, the role of organic matrix and their interactions remains unclear. This study investigated the interaction among CO2 laser irradiation, fluoride, and the organic matrix on the demineralization of human enamel. Twenty-four molars were selected and cut into halves. One half of each tooth was depleted of its lipid and protein. The other half served as a matched control. Each tooth half had two window areas, treated with a 2.0% NaF gel. All left windows then received a laser treatment. Next, the tooth halves were subjected to a four-day pH-cycling procedure that created caries-like lesions. Tooth sections were cut from the windows, and microradiographs were used for quantification of the demineralization. The combined fluoride-laser treatment led to 98.3% and 95.1% reductions in mineral loss for enamel with and without organic matrix, respectively, when compared with sound enamel.

The effect of fluoridated and non-fluoridated rewetting agents on in vitro recurrent caries

OBJECTIVE

This study examined the in vitro caries inhibiting potential of fluoridated and non-fluoridated rewetting agents that are applied to acid-etched enamel and dentine before the use of a water-free, dentine adhesive.

MATERIALS AND METHODS

Twelve caries-free premolars were divided into three groups of four teeth each. 2 x 3 x 1.5 mm cavities were prepared on the mesial and distal surfaces of each tooth, with half of the cavosurface margin in enamel and half in root dentine. In Group I (control), One-Step (Bisco, Schaumburg, USA) was applied without etching or rewetting agents. In Group II, cavities were acid-etched, rinsed, dried, and rewetted with Aqua-Prep (Bisco), a non-fluoridated rewetting agent, and then bonded with One-Step. Treatment for Group III was similar to Group II, except that Aqua-Prep F (Bisco), a fluoridated rewetting agent was used. Bonded cavities were restored with a non-fluoride-containing flowable composite (AEliteFlo, Bisco). Artificial carious lesions were induced in these specimens, from which multiple 100+/-20 microm thick longitudinal sections were prepared, yielding 16 specimens per group for evaluation with polarised light microscopy (PLM) and microradiography (MRG). Representative sections were processed for transmission electron microscopy (TEM) examination and scanning transmission electron microscopy/energy dispersive X-ray (STEM/EDX) analyses.

RESULTS

The differences in demineralisation of dentine among the groups were not statistically significant for 'relative' lesion depth (p > 0.05, ANOVA, Student-Neuman-Keuls test), but highly significant for 'relative' lesion area (p < 0.001). Wall lesions were consistently present in Group I, while inhibition zones were invariably observed in Group III. 87.5% of Group II specimens exhibited neither wall lesion nor inhibition zone. TEM showed that remnant dentine apatite crystallites within the inhibition zones in Group III were larger and denser than those present within the corresponding wall lesions. STEM/EDX analyses confirmed the presence of calcium, phosphorus and fluorine in these plate-like crystallites.

CONCLUSION

When used with a water-free, single-bottle dentine adhesive, a non-fluoridated rewetting agent is able to reduce, but cannot completely prevent recurrent caries. The use of a fluoridated rewetting agent is useful under the situation when microleakage occurs, by providing the additional benefit of fluoride-induced demineralisation inhibition.

Effects of low-energy CO2 laser irradiation and the organic matrix on inhibition of enamel demineralization

In the past two decades, accumulated evidence has clearly demonstrated the inhibitory effects of laser irradiation on enamel demineralization, but the exact mechanisms of these effects remain unclear. The purpose of this study was to investigate the effects of low-energy CO2 laser irradiation on demineralization of both normal human enamel and human enamel with its organic matrix removed. Twenty-four human molars were collected, cleaned, and cut into two halves. One half of each tooth was randomly selected and its lipid and protein content extracted. The other half of each tooth was used as the matched control. Each tooth half had two window areas. All the left windows were treated with a low-energy laser irradiation, whereas the right windows served as the non-laser controls. After caries-like lesion formation in a pH-cycling environment, microradiographs of tooth sections were taken for quantification of demineralization. The mean mineral losses (with standard deviation) of the enamel control, the lased enamel, the non-organic enamel control, and the lased non-organic enamel subgroups were 3955 (1191), 52(49), 4565(1311), and 1191 (940), respectively. A factorial ANOVA showed significant effects of laser irradiation (p = 0.0001), organic matrix (p = 0.0125), and the laser-organic matrix interaction (p = 0.0377). The laser irradiation resulted in a greater than 98% reduction in mineral loss, but the laser effect dropped to about 70% when the organic matrix in the enamel was removed. The results suggest that clinically applicable CO2 laser irradiation may cause an almost complete inhibition of enamel demineralization.

Factors affecting dentifrice use and ingestion among a sample of U.S. preschoolers

PURPOSE

This study was performed to assess the actual amount of dentifrice used and ingested and factors associated with use/ingestion among 28 U.S. preschoolers aged 40 to 48 months.

METHODS

Using their regular dentifrice brands/flavors and small child-sized toothbrushes (Oral -B 5), the participants or their parents placed dentifrice on toothbrushes three times to assess the quantity used and its consistency. Their brushing behaviors were observed and the amounts of dentifrice ingested were indirectly measured. Afterward, the parents and children placed a "pea-sized" amount of dentifrice on their toothbrushes.

RESULTS

The participants were generally consistent in quantity applied, averaging 0.256 g (range 0.035 g-0.620 g; standard deviation 0.177 g) of dentifrice per brushing. Children, either alone or with parental assistance, placed more dentifrice than either mother or father alone (P = 0.007). The estimated mean ingested fluoride was 0.17 mg F per brushing, an average of 62% of the amount of dentifrice used (range up to 98%). Amount of ingested fluoride was positively associated (P < 0.05) with the amount of dentifrice used, and negatively associated with parental assistance in brushing. When asked to apply a pea-sized quantity, the mean quantity applied was 0.314 g (range 0.064 g-0.521 g).

CONCLUSIONS

This study further supports the use of small amounts of dentifrice in young children, because they ingest substantial proportions of dentifrice.

Assessment of the effect of selected snack foods on the remineralization/demineralization of enamel and dentin

This study utilized volunteer subjects to examine caries-like lesions for remineralization and demineralization patterns in dentin and enamel when nine different snack foods were eaten between meals. Caries progression was observed in enamel and dentin when apple juice, a cola beverage, and sweetened (strawberry) yogurt were consumed as snacks. Remineralization of enamel was observed when cheddar cheese, skim milk, 2% milk, whole milk, chocolate milk, and orange juice were used as between meal snacks. Dairy products, with the exception of the sweetened yogurt, generally reduced the amount of demineralization produced in dentin. This study helps establish a scientific basis for appropriate between-meal snacks for patients who are concerned about their dietary habits as a part of their overall preventive oral health plan.

The effect of different commercial dentifrices on enamel lesion progression: an in vitro pH-cycling study

AIMS/OBJECTIVES

To evaluate and compare the de/remineralization effects of dentifrices manufactured locally in some developing countries.

DESIGN

Utilisation of the in vitro single-section and the pH-cycling model.

SETTING

Laboratory. TEST MATERIALS: Dentifrices: Maxam DFP, Maxam Tartar Control, First, Tianqi Medicated from China; Vicco Vajradenti from India; Colgate MFP2, Crest Tartar Control from USA; and one non-fluoride dentifrice as control.

METHODS

Sound molars were painted, leaving a 1 mm wide 'window' on the buccal and/or lingual surface and placed in a demineralisation solution for 96 h to produce artificial caries lesion approximately 80-100 mm deep. The teeth were then longitudinally sectioned (approximately 100 mm thick), and randomly divided into 8 groups (22 sections/group). The pH cycling model was utilised for 10 days.

OUTCOME MEASURES

Polarised light microscopy and microradiography were used to evaluate the lesion progression before and after treatment.

RESULTS

The control group showed an increase in lesion depth of 70 per cent and was statistically different from some test groups which ranged from -2 per cent to 68 per cent (P < 0.01, t-test). Statistically significant differences were also observed among some of the fluoride containing groups.

CONCLUSIONS

This study suggests that, when compared to 'multinational dentifrices', Chinese and Indian dentifrices manufactured locally failed to show 'healing' efficacy even though they claimed to contain varying levels of fluoride.

Morphology of initial lesions of enamel treated with different commercial dentifrices using a pH cycling model: scanning electron microscopy observations

The aim of this study was to evaluate and compare the 'calcium fluoride-like reaction products' formed, both on the surface and in the subsurface caries-like lesions of enamel, from different commercial dentifrices manufactured locally from developed and developing countries. The experiment was conducted by using the in vitro single-section technique under the pH-cycling system used for 10 days. The tested dentifrices include; Maxam DFP Maxam Tartar Controls, First, Tianqui Medicated (China); Vicco Vajradenti (India); Colgate MFP2. Crest Tartar Control (USA); and a non-fluoride dentifrice, Jie Yin (China) used as control. The surface and subsurface of the lesions, before and after treatment, were examined using scanning electron microscopy. Varying degrees of fine globular patterns of calcium fluoride-like material were observed on the enamel surfaces of five out of eight groups and in the subsurface of four groups. Two treatment groups showed a 'similar appearance' compared with the control and untreated groups. This study suggests and supports that, when compared with 'multinational dentifrices', some Chinese and Indian dentifrices manufactured locally failed to induce the typical morphological appearance of globules as seen with fluoride dentifrices.