The effectiveness of iontophoresis in reducing dentin hypersensitivity

Effect of Iontophoresis on the Effectiveness of Nano-Hydroxyapatite and Pro-argin in In-Office Treatment of Dentin Hypersensitivity: A Split-Mouth Randomized Clinical Trial

Background and objectives Dentin hypersensitivity (DH) treatment is one of the main challenges dentists face in their daily clinical practice. Current therapies provide only temporary relief and require multiple applications to exhibit results, and there is a lack of evidence related to the long-term effects of these agents. Nano-hydroxyapatite (n-HA) and pro-argin (8.0% arginine-calcium carbonate) have recently been used for dentin desensitization with a one-time in-office application, but the effects are interim. However, a standard treatment protocol demands definitive or enduring results. Since iontophoresis amplifies the transport of neutral and ionized drugs across a membrane, the use of these desensitizing agents with iontophoresis may be beneficial to accomplish satisfactory results. This study was conducted to evaluate whether iontophoresis could enable better penetration of nano-hydroxyapatite and pro-argin into the dentin, enhancing and prolonging their therapeutic effect. Materials and methods Forty-five participants with dentin hypersensitivity in the age group of 20 to 60 years were included. In each individual, four teeth with cervical lesions (one from each quadrant) were selected and divided randomly into four groups: group I: desensitizing paste containing nano-hydroxyapatite, group II: desensitizing paste containing nano-hydroxyapatite with iontophoresis, group III: desensitizing paste containing pro-argin, and group IV: desensitizing paste containing pro-argin with iontophoresis; followed by one-time application of the agents. Sensitivity was assessed by tactile, air blast, and cold-graded thermal tests (CGTTs) before and immediately after application, after one week, and at the end of the first, third, and sixth months. Statistical analysis Statistical analysis was done by repeated measures ANOVA for within-group comparison. Intergroup comparison was done using one-way ANOVA and Tukey's post-hoc test. Results All the groups showed a statistically significant reduction in dentin hypersensitivity (p<0.001). The reduction in hypersensitivity in various groups can be graded as group II (3.578/1.800/1.556) > group IV (3.367/1.755/1.555) > group I (2.3781/1.022/0.822) > group III (2.222/0.911/0.778) as evaluated by tactile, air blast, and cold-graded thermal tests, respectively. Group II and group IV presented a significant reduction in sensitivity levels consistent for up to six months. Conclusion Nano-hydroxyapatite and pro-argin can be used effectively for reducing dentin hypersensitivity. Iontophoresis can be a valuable adjunct for their improved delivery, enhancing and prolonging their effectiveness.

A comparative evaluation of propolis and 5.0% potassium nitrate as a dentine desensitizer: A clinical study

AIM

The purpose of this clinical study was to evaluate the efficacy of saturated ethanolic solution of Propolis for the treatment of dentin hypersensitivity.

MATERIALS AND METHODS

Ten patients aged 20-40 years with 156 hypersensitive teeth were selected for a 3-month study. Each patient was subjected to treatment with saturated ethanolic solution of Propolis, 5% potassium nitrate and distilled water. The patients were recalled at seventh day, 2 weeks and 4 weeks for the application of the agent and re-evaluation. The final re-evaluation of the patients was done after 3 months from the first application. The responses of the patients to the test temperatures were converted to a ranking and data was statistically analyzed. A statistical analysis was done using ANOVA and Bonferroni test and Tukey HSD test for multicomparison.

RESULTS

The results between the Propolis group and the potassium nitrate group showed no significant difference in the immediate post-treatment period; however, the results were significant at the end of first week and second week. At 4 weeks and 3 months period, a comparison between the groups again showed no significant difference.

CONCLUSION

It was concluded that Propolis was more effective than 5% potassium nitrate in relieving dentinal hypersensitivity and had an immediate and sustained effect.

Iontophoresis and electroporation: comparisons and contrasts

The techniques of iontophoresis and electroporation can be used to enhance topical and transdermal drug delivery. Iontophoresis applies a small low voltage (typically 10 V or less) continuous constant current (typically 0.5 mA/cm2 or less) to push a charged drug into skin or other tissue. In contrast, electroporation applies a high voltage (typically, ?100 V) pulse for a very short (micros-ms) duration to permeabilize the skin. This electric assistance of drug delivery across skin will expand the scope of transdermal delivery to hydrophilic macromolecules such as the drugs of biotechnology. These two techniques differ in several aspects such as the mode of application and pathways of transport but can be used together for effective drug delivery. Iontophoresis is already used clinically in physical therapy clinics and is close to commercialization for development of a systemic delivery patch with miniaturized circuits and similar in overall size to a passive patch. The use of electroporation for drug delivery is relatively new and is being actively researched.

Measurement of tooth hypersensitivity and oral factors involved in its development

The various methods of measurement of dentinal hypersensitivity are based upon the types of stimuli used to elicit a pain response in teeth, which include thermal, tactile, evaporative, electrical and osmotic. Pulpal inflammation in its early stages reduce the threshold of pain response to these stimuli but electrical stimulation may make it possible to assess the possible contribution of such inflammation to sensitivity determinations. Although the magnitude of each stimulus is quantifiable, patient response is subjective, which necessarily makes measurements of dentinal sensitivity semisubjective. Various methods of testing dentinal sensitivity are discussed, along with their advantages and disadvantages. The teeth most suited for measurement in clinical studies are the canines and premolars. This is because approx. 80% of the sensitivity lesions are associated with these teeth, which have similar thicknesses of root dentine. Data from several studies involving the same subjects indicate that individual measurements readily return to baseline and that the commonly seen placebo effect is probably due to some as yet unidentified factor in desensitizing formulations. Possible roles of salivary and plaque environmental factors in the development of dentinal sensitivity are discussed, as well as methods for their measurement.

Current strategies for dentist-applied treatment in the management of hypersensitive dentine

Few of the many dentist-applied treatments for dentine hypersensitivity meet the requirements of an ideal desensitizing agent'. This paper, although not exhaustive, covers methods that may be classified from simplest to most complex. Topical methods are simple, but they are often uncomfortable and the effects usually quite short-lasting, and many fall short of the 'ideal'. Fluorides and oxalates appear to be the best topical methods. Iontophoresis of fluoride represents an intermediate stage of complexity and it meets most of the criteria of an ideal desensitizing agent. Newer restorative materials, such as glass-ionomer cements and dentine bonding agents, are the most complex. These are still under investigation, but when the tooth needs recontouring, or in difficult cases that do not respond to other treatments, the dentist may choose to use a restorative material. Resin primers alone could be promising but the effects are not permanent and investigation into their use is still under way. Finally, laser treatment has been espoused for dentine desensitization. This requires extremely expensive equipment, must be dentist applied, and might produce pulpal irritation. Much more study is needed on restorative treatments and lasers before they can be considered as effective desensitizing agents. Until that research is completed, the dentist must choose one or more of the available methods in order to have a clinical therapy that is likely to relieve the symptoms of hypersensitive dentine.

Assessment of pain in cervical dentinal sensitivity studies. A review

Traditionally cervical dentinal sensitivity (CDS) has been evaluated mainly subjectively on the basis of the individual patient's subjective response, e.g., in the form of verbal rating and visual analogue scales and questionnaires. The stimuli used for evaluating this response can be grouped into 4 main categories: mechanical, chemical, electrical and thermal. This review of the literature, however, indicates that there are problems in evaluating patient subjective response to these various test stimuli used in the assessment and treatment of CDS. Opinions also vary as to the reliability of some of these methods of assessment, although recently, efforts have been made to develop controlled reproducible stimuli more suited to the evaluation of CDS. Currently no single method of eliciting and assessing CDS may be considered ideal. Further research is required to evaluate suitable methodology for the quantification of realistic test stimuli under controlled clinical conditions, whereby the subjective response may be objectively measured by the investigator.

Dentine hypersensitivity: a review

Dentine hypersensitivity is a relatively common pain condition. Local pulpal inflammation, traumatic oral hygiene and dietary habits have been considered in the etiology of dentine hypersensitivity. Dentine hypersensitivity is probably caused by a change in fluid flow in the dentinal tubules, which in turn excites the nerve endings located at the pulp-dentine border. Consequently, treatment success would depend on the prevention of fluid flow across the dentinal tubules (sodium fluoride, stannous fluoride, sodium monofluorophosphate, strontium chloride, sodium citrate, potassium oxalate, and resins/adhesives), or on the desensitization of the nerve endings located at the pulp-dentine border (potassium nitrate). Although a wide variety of treatment methods have been available, clinical data is characterized with ambiguity, warranting further research of the factors which could possibly be implicated in the occurrence of dentine hypersensitivity.

The effectiveness of a patient-applied tooth desensitizing gel. A pilot study

Potassium nitrate has been found to be an effective ingredient for reducing dentinal hypersensitivity. The purpose of this study was to evaluate the effectiveness of a patient-applied 10% potassium nitrate glycerine-based gel in decreasing dentinal sensitivity on cold on teeth with exposed dentin apical to the cemento-enamel junction, 12 patients, each having 3 hypersensitive teeth, were tested. The patients were divided into 3 treatment groups: group 1 was treated with a glycerine-based 10% potassium nitrate gel: group 2 was treated with a glycerine gel without potassium nitrate; and group 3 received no gel and no treatment (control). Following brushing and flossing, groups 1 and 2 applied the gel to the test teeth using custom-made soft acrylic trays, for a period of 5 min/day for 4 weeks. Patient responses to cold water stimuli of 20 degrees C, 10 degrees C and 0 degrees C, were measured at baseline (week 0), then at 1-, 2-, 3- and 4-week intervals. Group 1 patients showed a significant decrease in sensitivity to cold at week 2 only. The group 2 patients showed a significant decrease in sensitivity to cold after 3 and 4 weeks. A statistically significant decrease in sensitivity was noted between group 2 and group 3 patients at week 3. The most sustained decrease in sensitivity to cold was found on teeth treated with plain glycerine.

Evaporative water loss from human dentine in vitro

The rate of spontaneous evaporation of water from dentine was measured in extracted human teeth in vitro. Spontaneous water loss was the same with or without a smear layer. When air was blown on the dentine, the rate of evaporation increased significantly. After removal of the smear layer, the air blast-induced evaporative loss was twice as great as before its removal. Thus, with a smear layer present, evaporation is the major route by which fluid is lost from dentine rather than by filtration of dentinal fluid. After smear layer removal, fluid filtration sometimes may exceed the spontaneous rate of fluid evaporation.