Annual review of selected dental literature: report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

Review of expandable dental implants

In the last few years the dental implants market has grown both in developed and developing countries, and is associated with high aesthetic expectations and well-being. Although the success rate of commercial implants is high, some problems associated with a lack of initial stability, marginal bony resorption, and periodontal health, remain, especially with immediate placement and loading. The market offers different designs of dental implants, but cylindrical and tapered devices that are fixed to the bone via an external thread are dominant. One lesser-known but potentially useful design is the expandable dental implant (EDI). This paper presents a review of expandable dental implants that encompasses a survey of the literature, published patents, and available commercial devices. We found 15 articles: prospective human trials (n=4), human case reports (n=3), published independent discussions of other articles (n=2), three big animal trials (n=3), and in silico studies (n=3). A total of 73 published patents were found and two expandable dental implants are commercially available to date. We propose a classification system that differentiates between the expansion mechanism and the origin of the expanding action. Some expandable designs have been shown to provide good primary stability, but evidence to date is limited. We encourage future clinical and biomechanical studies to clarify and optimise the potential benefits of these implants.

Effect of topical fluoride on microshear bond strength of primary enamel to composite, microhardness of enamel and its surface morphology: An in vitro study

Background. This in vitro study aimed to evaluate the microshear bond strength (μSBS), microhardness and morphological characteristics of primary enamel after treating with sodium fluoride (NaF) and acidulated phosphate fluoride (APF).

Methods. Forty-eight primary canines were cut into mesial and distal sections and assigned to five groups randomly: group 1 (immersed in saliva as a control), group 2 (treated with NAF and immersed in saliva for 30 minutes), group 3 (treated with APF and immersed in saliva for 30 minutes), group 4 (treated with NAF and immersed in saliva for 10 days), and group 5 (treated with APF and immersed in saliva for 10 days). Composite resin (Filtek Z250) was bonded on the specimens (n=15) for measuring the μSBS. After storage in 37°C artificial saliva for 24 hours, µSBS and Vickers hardness tests (10 readings) were performed. The data were analyzed using one-way ANOVA and Kolmogorov-Smirnov, Levene’s and Tukey HSD tests (P<0.05). Morphological analysis of enamel and modes of failure were carried out under a scanning electron microscope (SEM) on two remaining specimens.

Results. Significant differences in μSBS were only noted between groups 2 and 4 (P=0.024). Group 3 showed a significant decrease in hardness after storage in artificial saliva (P<0.001), with a significantly lower hardness than the other groups (P<0.001). The SEM observations showed irregular particles in groups 3 and 5; uniform, smooth and thin coats were seen in groups 2 and 4.

Conclusion. Fluoride therapy with NaF and APF gels prior to restorative treatments had no adverse effects on the microshear bond strength.

Occlusal stabilization appliance: evaluation of its efficacy in the treatment of temporomandibular disorders

Occlusal stabilization appliances or splints are the most widely employed method for treatment of temporomandibular disorders (TMD). Magnetic Resonance Imaging (MRI) is the most indicated imaging modality to evaluate the components of the temporomandibular joint (TMJ). Forty patients with signs and symptoms of temporomandibular disorders were treated with splints for a mean period of 12 months, comprising regular semimonthly follow-ups. After stabilization of the clinical status, occlusal adjustments and MRI evaluation were performed. It was concluded that the success of this kind of treatment are related to the total (70%) or partial improvement (22.5%) of painful symptomatology and to the functional reestablishment of the craniomandibular complex. The MRI allowed evaluation and also the conclusion that the splints provide conditions for the organism to develop means to resist to the temporomandibular disorders by means of elimination of several etiologic factors. Moreover, after treatment the patients are able to cope with disc displacements with larger or smaller tolerance.

Effect of Antibacterial Varnishes Applied to Root Dentin on Shear Bond Strength of Tooth-colored Restorative Materials

The application of antibacterial varnish affects the shear bond strength of tooth-colored restorative materials after six months.

Amine fluoride/stannous fluoride and incidence of root caries in periodontal maintenance patients. A 2-year evaluation

AIM

The purpose of the present study was to evaluate in a group of periodontal maintenance patients, the effect of using a dentifrice and mouthrinse containing amine fluoride (AmF) and stannous fluoride (SnF2) as compared with a dentifrice and mouthrinse both containing sodium fluoride (NaF) with regard to their root caries experience.

MATERIAL

In total, 80 patients who had been treated for moderate-to-severe periodontitis agreed to participate in this study. Subjects received supportive periodontal therapy at regular intervals of 3-4 months for at least a period of 1 year. The patients were randomly divided into two groups: (1) the test group used an AmF/SnF2 dentifrice and mouthrinse and (2) the control group used an NaF-containing dentifrice and mouthrinse. Root caries was recorded at four sites per tooth at baseline and 24 months.

RESULTS

An increase in number of the exposed root surfaces was noted for both groups during the experimental period (p<0.05). The mean number of active caries lesions at baseline was 2.1 and 1.8 for the test group and control group, respectively. At 24 months, the corresponding values were 1.8 for the test and 2.2 for the control group. An increase of the mean number of restored surfaces was noted for the AmF/SnF2 group (from 7.3 to 13.4) and the control group (from 7.9 to 14.7) during the course of the study. This increase was found to be statistically significant for both groups in comparison with the baseline values (p< or =0.01). No statistically significant differences were noted between groups. Further analysis of the restored surfaces revealed that the major increase in number of the restorations was associated with restorations involving three to four root surfaces in the same tooth. Molars and premolars were the teeth receiving most new restorations.

CONCLUSION

The present study did not detect a difference in terms of root caries development between the two groups. Root caries development is a common finding associated with surfaces developing recession in patients once treated for periodontal problems.

Clinical reversal of root caries using ozone, double-blind, randomised, controlled 18-month trial

OBJECTIVE

To assess the effect of an ozone delivery system, combined with the daily use of a remineralising patient kit, on the clinical severity of non-cavitated leathery primary root carious lesions (PRCL's), in an older population group.

DESIGN

A total of 89 subjects, (age range 60-82, mean +/- SD, 70.8 +/- 6 years), each with two leathery PRCL's, were recruited. The two lesions in each subject were randomly assigned for treatment with ozone or air, in a double-blind design, in a general dental practice. Subjects were recalled at three, six, 12 and 18 months. Lesions were clinically recorded at each visit as soft, leathery or hard, scored with a validated root caries severity index.

RESULTS

There were no observed adverse events. After three months, in the ozone-treated group, 61 PRCL's (69%) had become hard and none had deteriorated, whilst in the control group, four PRCL's (4%) had become worse (p<0.01). At the six-month recall, in the ozone group, seven PRCL's (8%) remained leathery, the remaining 82 (92%) PRCL's had become hard, whilst in the control group, 10 PRCL's had become worse (11%) and one had become hard (p<0.01). At 12 and 18 months, 87 Subjects attended. In the ozone group at 12 months, two PRCL's remained leathery, compared to 85 (98%) that had hardened, whilst in the control group 21 (24%) of the PRCL's had progressed from leathery to soft, i.e. became worse, 65 PRCL's (75%) were still leathery, and one remained hard (p<0.01). At 18 months, 87 (100%) of ozone-treated PRCL's had arrested, whilst in the control group, 32 lesions (37%) of the PRCL's had worsened from leathery to soft (p<0.01), 54 (62%) PRCL's remained leathery and only one of the control PRCL's had reversed (p<0.01).

CONCLUSIONS

Leathery non-cavitated primary root caries can be arrested non-operatively with ozone and remineralising products. This treatment regime is an effective alternative to conventional "drilling and filling".