The desensitizing effect of calcium hydroxide and magnesium hydroxide on hypersensitive dentin

In-office treatment of dentinal hypersensitivity

Dentinal hypersensitivity is a common dental complaint, especially in periodontal patients. It is believed to be mediated by a hydrodynamic mechanism in which various stimuli result in increased fluid flow in dentinal tubules, thereby generating action potentials in associated nerve fibers. Although it is often perceived as mild discomfort by the patient, it can be severe. A variety of interventions has been used, although few have been subjected to rigorous study. This article surveys those in-office treatments that are available, and suggests directions for research so that clinicians may treat patients based on best evidence. Until such evidence is available, it seems prudent to employ therapies that are least likely to cause harm and are reversible.

Effect of a 3% Potassium Oxalate Topical Application on Dentinal Hypersensitivity After Subgingival Scaling and Root Planing

BACKGROUND

The present study aimed to verify the effect of a single application of 3% potassium oxalate gel compared to a placebo gel immediately after subgingival scaling and root planing (SRP) on dentinal hypersensitivity (DH).

METHODS

Fifteen patients undergoing periodontal treatment volunteered for this randomized controlled clinical trial. They presented with periodontitis on homologous contralateral canines and premolars, with complaints of dentinal hypersensitivity before periodontal therapy. Immediately after SRP under local anesthesia, the test and placebo agents were randomly applied on the cemento-enamel junction. Evaluation of DH reduction after treatment was self-reported, with assessment made by the patient's indication of how painful each treated. tooth was on a visual analog scale (VAS) at baseline, and 7, 14, and 21 days post-treatment. The results were analyzed by DH percent reduction for each observational moment in relation to baseline, for test and control teeth separately. Mean percent reductions for each group were compared by paired sample t test, with an alpha level of 0.05.

RESULTS

On day 7, percent reduction for the test and control groups was 29.4% and 13.4%, respectively. On day 14 it was 64.6% and 20.5%, and on day 21 it was 81% and 34.7%, respectively. Significant differences between treatments were observed at 14 and 21 days.

CONCLUSION

It may be concluded that subgingival scaling and root planing followed by a single application of a 3% potassium oxalate gel resulted in a significantly higher reduction of dentinal hypersensitivity at 14 and 21 days, when compared to the placebo.

Comparison of using calcium hydroxide or a dentine primer for reducing dentinal pain following crown preparation: a randomized clinical trial with an observation time up to 30 months1

The purpose of this study was to evaluate effect of a calcium hydroxide suspension [Ca(OH)2] or glutaraldehyde based dentine primer (GDP) to reduce tooth sensitivity after full crown preparation. Thirty-six patients were treated with Ca(OH)(2) on one tooth and with GDP on another. Patients completed a questionnaire regarding sensitivity during crown preparation, when the not-anaesthetized abutments were irritated [cotton pellet (20 degrees C)]. The teeth were tested before (T(0)) and after using the desensitizer (T(1)), again after 7 days (T(2)), 6 months (T(3)) and 30 months (T(4)). The results were registered on a visual analogue scale [0 (no pain)-100 (severe pain)]. The changes of tooth sensitivity between different testing times were analysed. The median and the (interquartile range) for the different time intervals for Ca(OH)(2) were DeltaT(0)-T(1): 5 (6-17), DeltaT(0)-T(2): 17 (14-32), and for GDP, DeltaT(0)-T(1): 9 (7-18) DeltaT(0)-T(2): 18 (16-33), the decreases in sensitivity were lower for DeltaT(0)-T(1) than for DeltaT(0)-T(2) for both desensitizers (P < 0.001). There was no statistical difference (P > 0.05) between the agents (DeltaT(0)-T(1), DeltaT(0)-T(2), DeltaT(3)-T(4)). Both substances might be useful in reducing tooth sensitivity after crown preparation, but no differences in the efficacy were found when comparing the materials.

A split-mouth placebo-controlled study to determine the effect of amorphous calcium phosphate in the treatment of dentine hypersensitivity

Many treatments for dentine hypersensitivity are formulated to directly or indirectly occlude the open dentinal tubules associated with the condition. Combining solutions of calcium chloride and potassium phosphate can result in the precipitation of amorphous calcium phosphate. Such a system applied to exposed dentine could occlude dentinal tubules and reduce sensitivity. The aims of this study using a placebo control were to assess the therapeutic value of amorphous calcium phosphate in dentine hypersensitivity and provide further information on the apparently natural improvement in the condition frequently observed in clinical trials. 38 subjects with dentine hypersensitivity affecting 1 tooth in each left and right sides of the jaws were recruited into this split mouth, randomised, double-blind study. At baseline, sensitivity was scored by the subjects on a 0-10 visual apologue scale after tactile, cool and cold water and evaporative stimulation of the test teeth. Active and control, water, solutions were then applied by a 2nd clinician. After 24 h, subjects returned for rescoring. On days 7 and 14, subjects were again rescored and the treatments reapplied. Further follow-up appointments for rescoring were on days 21, 28, 56 and 84. Plaque scores also were recorded from test teeth at each visit. Overall sensitivity decreased considerably and to a similar degree in test and control teeth with no consistent significant treatment difference. Plaque scores also decreased through the study period. It is concluded that either the amorphous calcium phosphate was without therapeutic effect or the activity was masked by the placebo response in the control teeth.

HIPERSENSIBILIDADE DENTINÁRIA: DIAGNÓSTICO E TRATAMENTO

A hipersensibilidade é a sensibilidade exagerada da dentina quando exposta ao meio bucal, que se torna permeável à ação de estímulos agressivos. O diagnóstico é feito através da anamnese e da inspeção clínica minuciosa. O tratamento pode ser feito pelo profissional ou pelo próprio paciente sob orientação, dependendo do caso. Ela ocorre comumente no final da terceira década, sendo ligeiramente mais freqüente nas mulheres do que nos homens.

Dentine hypersensitivity and the placebo response. A comparison of the effect of strontium acetate, potassium nitrate and fluoride toothpastes

A considerable number of varied agents are apparently effective in the treatment of dentine hypersensitivity. In particular, the literature supports the efficacy of strontium, potassium and fluoride containing toothpastes. This study was a double-blind, randomised, parallel group comparison of three products, namely strontium- and potassium-based desensitising toothpastes both containing fluoride, and a conventional fluoride toothpaste. A total of 131 subjects entered a 4-week wash-in phase using the conventional fluoride toothpaste, of whom 120 entered a 6-week treatment phase. Sensitive teeth were evaluated at wash-in baseline, treatment baseline and after 2 and 6 weeks use of the treatment pastes. Dentine hypersensitivity was assessed with tactile and cold air stimuli together with an overall subjective assessment. Analysis of the findings was performed using non-parametric statistical methods. Of the original 120 subjects, 112 completed the trial. All 3 toothpaste groups showed reductions in sensitivity over the 6 weeks; however, no significant differences were found between the three products at any given time. Interestingly, there was no significant change in sensitivity between wash-in baseline and treatment baseline for the cold air stimulus with the fluoride-only-based paste. However, for the group using the same fluoride toothpaste, there was significant improvement between wash-in baseline and week 6, and treatment baseline and week 6 for this stimulus, suggesting a substantial placebo effect occurred. There is a need for further investigation of a wash-in period and examination of the placebo effect when evaluating dentine hypersensitivity trials.

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.

Calcium hydroxide in restorative dentistry

This paper reviews the various calcium hydroxide preparations available for use in restorative dentistry and their constituents. The significance of individual constituents in relation to the properties of such materials and their mode of therapeutic action with respect to the dentine pulpal response and antibacterial activity is discussed. Applications of calcium hydroxide in restorative dentistry are also reviewed.

Decreasing intradental nerve activity in the cat with potassium and divalent cations

Nerve activity was recorded from deep dentinal cavities in the canine teeth to assess the possible influence of potassium and divalent cations in decreasing this activity in hypersensitive teeth. The decreased activity after the topical application of 0.756 mol/l KCl to the cavity was primarily due to the cation. KCl elicited a biphasic response from intradental nerves, an initial transient excitatory response followed by a prolonged inhibitory period. During the inhibitory period 3 mol/l NaCl, an effective excitatory stimulus, failed to evoke intradental nerve activity. However, with time the response to 3 mol/l NaCl eventually recovered to its previous control level. Close, intra-arterial injection of KCl showed the same biphasic response and time-course of intradental nerve activity as with topical application. Therefore, whether KCl was applied topically or injected its effectiveness in altering the nerve activity was similar. Pretreatment of the dentinal cavity with CaCl2, MgCl2 or SrCl2 greatly reduced the response of intradental nerves to KCl. Therefore these divalent cations seem to have a depressant action on pulpal nerve fibres. The mechanism of action of KCl seems to be an alteration of K+ concentration immediately surrounding the intradental nerves which presumably depolarizes the nerve fibre membrane and elicits an initial firing of action potentials. Because of the persisting high levels of extracellular potassium a sustained depolarized state occurs that results in an inactivation of the action potential. Divalent cations appear to depress the excitability of the nerve cell membrane without altering membrane potential. Such ionic agents could be used in conjunction with KCl as a possible treatment for hypersensitive teeth.

Effect of a desensitizing dentifrice on dentinal hypersensitivity

The objective of this study was to assess the effectiveness of a dentifrice with 2% dibasic sodium citrate in poloxamer 407 in decreasing dentinal hypersensitivity. The test toothpaste was compared with a control toothpaste containing 0.76% sodium monofluorophosphate in a 6-week double-blind clinical trial. A total of 75 hypersensitive teeth were examined in the test group, while 100 hypersensitive teeth were in the control group. Changes in hypersensitivity levels were monitored after 6 weeks, using thermal, chemical and mechanical stimuli. At the end of 6 weeks, the test dentifrice was not significantly more effective than the control in decreasing dentinal hypersensitivity. Of the stimuli used, cold was the most effective in eliciting a hypersensitive response, followed by chemical stimulation and air. Heat and toothbrushing caused the least discomfort.

Cyanoacrylate--a new treatment for hypersensitive dentin and cementum

Hypersensitivity that causes chronic pain and discomfort in exposed cementum and dentin, and the various therapeutic agents and treatment regimens that have been tried to alleviate this condition are considered. The desensitizing effects of cyanoacrylate compared with 33% sodium fluoride paste were evaluated for 6 weeks.

Hypersensitive teeth. Part II: Treatment

If the hydrodynamic theory for pain transmission were accepted, occlusion of the patent dentinal tubules would appear to be essential for treatment efficacy. There are many compounds with seemingly varied chemical forms that have been shown to be effective. Their exact mode of action however, is not clearly defined because well-designed, nonbiased, and controlled comparison studies between agents are lacking. The various toothpastes may have ingredients that actually occlude patent tubules or they may cause secondary desensitization by irrational or abrasive action. In any pain study, the nature of the placebo effect and other psychogenic factors play a significant role. Fluoride preparation with and without iontophoresis has been shown to alter tubule structure and form microprecipitates. The natural desensitization process, although slow, is nature's protection, allowing dentinal sclerosis of secondary dentin formation. Although the resin-adhesive systems, especially the new light-cured dentin bonding agents, appear immediately to be effective, the effect on the pulp remains unknown. Perhaps a combination of iontophoresis with sodium fluoride and light-cured dentin bonding material may yield protection and desensitization at a high level of predictability. With the population trends toward a more geriatric society, further research, knowledge, and understanding of dentinal hypersensitivity is of paramount importance. The expected increase in longevity of the dentition suggests that dentin exposure and sensitivity will increase as a clinical problem. There is a clear time-age relationship involved in gingival recession, erosion and attrition of the teeth, and the need for periodontal surgical therapy. For total comprehensive care, patient comfort is important and should be provided along with sound periodontal health and ideal restorative function.

Controlled trial of the action of a toothpaste containing nicomethanol hydrofluoride in the treatment of dentine hypersensitivity

A double-blind clinical trial was performed on 76 patients with dentine hypersensitivity. For four weeks the patients used either a toothpaste containing nicomethanol hydrofluoride or one containing potassium nitrate and sodium monofluorophosphate. After one, two and four weeks the pain responses of the teeth to three types of stimuli were assessed. In normal conditions of oral hygiene, the nicomethanol hydrofluoride toothpaste was found at least as effective as the potassium nitrate/sodium monofluorophosphate preparation.

The effects of calcium hydroxide on dentin permeability

Calcium hydroxide paste was applied to human dentin in vitro to determine its effects on dentin permeability. Discs of dentin were acid-etched on both sides to permit determination of their maximum permeability. Smear layers were then applied to the enamel sides of the discs, thereby reducing dentin permeability 99%. Topical application of Ca(OH)2 paste to the smear layer reduced dentin permeability further, to levels 48% below that of untreated smear layers. When the Ca(OH)2-treated smear layers were exposed to 6% citric acid for two min, dentin permeability returned to the initial acid-etched value, demonstrating that Ca(OH)2 offers little protection to acid challenge. Treatment of acid-etched dentin with Ca(OH)2 produced a similar reduction in dentin permeability, which was restored to normal following acid challenge. Thus, Ca(OH)2 is effective at reducing the permeability of both the smear layer and of acid-etched dentin, in vitro.

Dentinal sensation and hypersensitivity. A review of mechanisms and treatment alternatives

Dentinal hypersensitivity has long been a dilemma of both dentists and patients. With teeth being maintained longer, there has been an increased demand placed upon the dentist to manage the sensitivity of cervically exposed dentin. There has been much written on this subject. The purpose of this review is to summarize the current concepts thought to be responsible in dentinal sensation, and to review and critique the various treatment modalities for dentinal hypersensitivity.

Dentine hypersensitivity--a review. Clinical and in vitro evaluation of treatment agents

A large number of compounds have been employed in the management of dentine hypersensitivity. The symptomatic nature of the condition and its variability poses many problems to any evaluation of effect. Several semi-quantitative methods of response have been used; however, at this time it is uncertain what advantages they hold over the patients' subjective assessment of improvement. A review of the clinical studies reveals that a positive result for every agent tested to date may be found. Nevertheless considerable placebo responses have been obtained and equivocal results are occasionally reported. The fluorides and metal salts, particularly of strontium, have been most studied when used either in solution or delivered in toothpaste formulations. For these compounds the literature contains considerable information concerning the reaction with dental hard tissues which can be extrapolated into hypotheses for the modes of action in relieving dentine hypersensitivity. Moreover, some in vitro studies provide useful information concerning the effects of certain compounds on dentine, and are consistent with the clinical data. Unfortunately, contradictory findings and anomalies between clinical and in vitro effects still prevent the development of a sound clinical basis for the treatment of the condition. Moreover, there is a need to recognise those factors which predispose to dentine exposure, if the prevention of the occurrence or re-occurrence of hypersensitivity is to be achieved.

The effectiveness of an electro-ionizing toothbrush in the control of dentinal hypersensitivity

The object of the investigation was to test the value of the 3M Brand Electro-Ionizing Toothbrush in the treatment of dentinal hypersensitivity. Eighty-eight volunteers were divided into three groups, each using different methods: (I) stannous fluoride dentifrice and 3M brush without a battery; (II) stannous fluoride dentifrice and 3M brush with a 1 1/2 volt battery; and (III) strontium chloride dentifrice and 3M brush without a battery. The volunteers brushed their teeth for 3 minutes twice a day for 12 weeks using one of the three test agents. The subjects were tested at weeks 0, 2, 4, 8 and 12 by means of a cold water spray quantitated by a temperature probe. All three groups experienced improvement and by week 12 Groups II and III displayed much less sensitivity than did Group I. At the end of the 12 weeks the subjects were questioned as to benefit of treatment. The questionnaire revealed that stannous fluoride with the ionizing brush provided significantly greater relief than did the stannous fluoride alone.

The effects of desensitizing agents on the hydraulic conductance of human dentin in vitro

The hydrodynamic theory of dentin sensitivity states that a stimulus applied at the orifice of exposed dentinal tubules causes movement of tubular fluid which stimulates nerve receptors. The fluid should obey principles of fluid movement through capillary tubes. Any decrease in the functional radius of the dentinal tubules should greatly reduce the rate of fluid flow, thus reducing dentinal sensitivity. The purpose of this study was to evaluate the ability of agents that have been used previously for clinical dentin desensitization to reduce the rate of fluid flow through dentin in vitro. Dentin discs prepared from extracted human third molars were treated with 50% citric acid to remove debris from tubular orifices. After placing the discs in a split chamber device, the rate at which buffer solution could filter across the dentin under 240 cm of water pressure was measured. The occlusal side of the disc was then treated with an agent thought to desensitize dentin to determine if it reduced fluid flow rate. Discs that had more than a 50% reduction in flow rate were examined by scanning electron microscopy to determine if those agents that decreased fluid flow also partially occluded tubular orifices. This in vitro model provided a useful quantitative method for screening a host of preparations that have been used in the past to decrease dentin sensitivity.

Clinical evaluation of a new treatment for dentinal hypersensitivity

The effectiveness of potassium nitrate (5%, delivered in a low abrasive toothpaste vehicle) as a daily home treatment of dentinal hypersensitivity was evaluated in a 4-week, double-blind, parallel, comparative study of 27 subjects with the condition. Hypersensitivity levels in affected teeth were assessed by two quantifying methods--electrical stimulus and cold air stimulus--and by a subjective recall procedure. The results from these three methods of assessment indicate that potassium nitrate desensitizes hypersensitive teeth to a significant degree. The therapeutic response (decline in dentinal hypersensitivity) to potassium nitrate was evident within 1 week and increased continuously for the length of the study period. Sensitivity threshold of teeth adjudged to be normally sensitive were not altered by treatment with potassium nitrate, nor did the agent exert any discernable effects on oral tissues.

Reactions of the dental pulp to microbial provocation of calcium hydroxide treated dentin

The purpose of the present study was to determine whether treatment of dentin with calcium hydroxide reduces pulp irritation caused by microbial products. The experiment was carried out in three young monkeys. Cavities were prepared on the buccal tooth surface deep into dentin of 62 teeth. Calcium hydroxyde mixed with distilled water was placed in one group of cavities. A set of control cavities received treatment with saline soaked filter-paper discs. The calcium hydroxide dressing and the saline discs were separated from the oral cavity for a period of 14 or 60 d by a Teflon disc and a layer of zinc oxide-eugenol cement. At the end of these periods the content of each cavity was removed and substituted by lyophilized material from cultivated plaque bacteria. After 3 d of exposure the monkeys were killed and the teeth subjected to histologic treatment. Assessments made in the light microscope revealed that pulps subjacent to calcium hydroxide-treated dentin in the majority of cases showed no or only slight infiltrates of inflammatory cells. In controls, 13 out of 22 pulps showed severe inflammatory cell infiltrates or total pulp tissue necrosis. It was concluded that treatment of dentin with calcium hydroxide may reduce the possibility for bacterial components to cause pulp tissue damage.

A new desensitizing dentifrice: preliminary report

Dentin sensitivity is one of the most painful, ubiquitous, and least satisfactorily treated chronic problems of the teeth. The purpose of this clinical trial was to test the sensitivity-reducing effectiveness of five dentifrices over a six-week period. For the study, 176 adults, ages 18 to 63, exhibiting a total of 486 hypersensitive surfaces, were randomly allocated to five experimental groups to use one of the following: a strontium chloride dentifrice, a 0.4% stannous fluoride gel, a pluronic F-127-sodium citrate gel, a pluronic F-127 gel, or a control dentifrice. No specific instructions were provided as to the frequency or method of toothbrushing; thus, the participants brushed their teeth in their usual manner. The analysis of the data was limited to 168 persons who complied with study procedures. Chi-square analysis examined the statistical differences between the four test agents and the control formulation. The desensitizing effect of the pluronic plus sodium citrate gel was highly significant, and the plain pluronic F-127 preparation was effective to a lesser degree. Patients using the strontium chloride or stannous-fluoride-containing dentifrices did not exhibit a significant improvement over the control group. This study demonstrated that a pluronic polyol gel containing sodium citrate is highly effective in controlling tooth hypersensitivity.

The effect of calcium hydroxide and fluorides on human dentine

With the aid of scanning electron microscopy and microradiography, 45 teeth including 20 contralateral tooth pairs were studied to assess the effect on human dentine of (1) a 1 minute treatment with 3% NaF, (2) a dressing of Ca(OH)2 and (3) a dressing of Ca(OH)2 and CaPO3F after follow-up periods of 2-8 weeks. After NaF treatment the SEM revealed no sign of obliteration of the dentinal tubules, and on microradiograms no indication of increased density could be registered compared to an untreated control area. Under the calcium dressing the SEM revealed in 13 cases out of 20 (5 cases of 11 intrapair comparisons) a varying degree of constriction of the dentinal tubules. Constrictions varied from one tubule to another and ceased approximately 0.1 mm in the dentine. On the microradiograms no significant difference could be registered between untreated dentine and dentine treated with the calcium dressings. Dressings of Ca(OH)2 a combination of Ca(OH)2 and CaPO3F for 2 months, or a 1 minute treatment with a cavity cleaner containing 3% NaF can thus not be considered to result in a reliable obliteration of the dentinal tubules.