The Efficacy of Casein Phosphoprotein-Calcium Phosphate Complex (CD-CP) [Dentacal^RTM] as a Mouth Moistener in Patients with Severe Xerostomia.
KD Hay and RP Morton (published in the New Zealand Dental Journal 99, No.2 46-48: June 2003)

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Abstract

Objectives

The purpose of this study was to evaluate casein derivatives coupled with calcium phosphate (CD-CP) (Dentacal^RTM, NSI Pty Limited., Hornsby, Australia) as a mouth moistener in a group of dental patients with severe xerostomia.

Design

The study was a subjective, patient self-evaluation questionnaire on the use of Dentacal compared with the moistening strategies that they usually used.

Setting

The study was hospital and community based.

Subjects/Materials, and Methods

Thirty eight patients with severe xerostomia were recruited from the larger group of 124 who had taken part in a clinical trial of the anti-caries efficacy of casein derivatives complexed with calcium phosphate (Hay and Thomson, 2002). Each patient used Dentacal for 14 days and the responses to it were compared with the responses to their other mouth moistening strategies.

Results

The outcome indicated that Dentacal, when used as an atomised spray in the mouth, provided good moistening and lubrication.

Conclusions

The material could provide benefits in both oral moistening and dental caries prevention in dentate people with xerostomia.

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Introduction

Patients who suffer from xerostomia, regardless of the cause, face two specific oral problems: the subjective and often extremely unpleasant effects of the dry mouth itself, and the greater risk of increased dental demineralisation and dental decay. While professional dental advisers of xerostomic patients need them to maintain immaculate oral health care regimens in order to minimise dental hard tissue destruction (Hay and Gear, 2002), it has also been shown that patients with dry mouth symptoms after radiotherapy for head and neck cancer are significantly more likely to be psychologically distressed than patients with little or no xerostomia (Bjordal and Kaasa, 1995). It has further been shown that, in people with Sjogren's disease, the presence of xerostomia has a marked effect on both pain in the mouth or throat and the physical functions of swallowing and appetite, although the severity of their xerostomia does not, perhaps surprisingly, appear to be an important determinant of psychological distress or overall quality of life (Hay et aI, 2001). In these two groups therefore, which constitute the majority of patients who experience it long-term, xerostomia can also be associated with significant functional and quality of life issues. In order to help overcome these problems most people, through trial and error, find methods to counter the effects of xerostomia, such as sipping water frequently, chewing gum, sucking sweets, and using artificial saliva. Some people use more than one method (Morton et al, ]997), if this helps to ameliorate the other associated subjective symptoms.

The findings of a recent study suggest that casein derivatives coupled with calcium phosphate (CD-CP) (NSI Pty Limited, Hornsby, Australia) is equivalent to sodium fluoride in its caries-preventive efficacy when used as a mouth) rinse in patients with severe xerostomia. During this trial it became clear from informal patient comments that the preparation could hold promise not only as a caries-preventive agent but also as a mouth moistener for such individuals, if used regularly throughout the day. Since the CD-CP formulation is non-toxic it would have a clear advantage over a fluoride-based preparation because it could be swallowed instead of spat out and, further, there would be no contra-indication to using it more than three times per day (Hay and Thomson, 2002).

The present study sought to evaluate the efficacy of CD-CP (DentacaIRTM, NSI Pty Limited, Hornsby, Australia) as a mouth moistener and to compare it with the usual mouth moistening strategies of a group of patients who had either Sjogren's disease or post-irradiation xerostomia.

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MATERIALS AND METHODS

Ethical approval for the study was obtained from the Auckland Ethics Committee.

A representative sample of 38 people with xerostomia, either as a result of Sjogren's disease or following radiotherapy to the major salivary structures, was recruited from the larger group of 124 who had taken part in the clinical trial of the anti-caries efficacy of casein derivatives complexed with calcium phosphate (Hay and Thomson, 2002). The patients were over 25 years of age, had more than 12 of their own standing teeth and had resting salivary flow rates of 0.1ml/minute or less. The Xerostomia Inventory [XI] score (Thomson et al, 1999) for each patient had been previously determined and was included in the database and analysis for the present study. An XI score of 20 has been shown to represent the mean score amongst a normal group, with higher scores indicating more adverse subjective responses to xerostomia (Thomson et al, 1999; Thomson and Williams, 2000).

At the initial interview, patients completed a questionnaire about their current mouth moistening strategies. They were also given the same questionnaire with a request to complete it a second time within the next few days and to return the documentation for validation of response consistency and reliability. The patients were then each given a 50ml atomiser spray bottle and a 1 litre container of Dentacal (3.6 percent by weight casein phosphoprotein-calcium phosphate complex), with instructions to decant the Dentacal into the atomiser bottle as required and to use this for mouth moistening instead of their usual strategy. Fourteen days later the patients were recalled, and completed a further questionnaire, using questions similar to the earlier questionnaire but evaluating the efficacy of Dentacal as the mouth moistener. The amount of material used was measured and the patients were invited to record any additional comments.

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RESULTS

Of the 38 patients recruited, 37 completed the study. The one patient who withdrew did so in the belief that the Dentacal had caused an exacerbation of pre-existing erosive lichen planus.

Test-retest analysis of the initial questionnaire showed that the questions were reliable. The percentage agreement for each question was more than 90 percent for half of the items and more than 75 percent for the others. Spearman (non-parametric) coefficients of correlation in the test-retest analysis of each question were between 0.60 and 0.82 and each was statistically significant.

The most popular usual mouth moistener was sipping water, favoured by 28 patients, 14 (50 percent) of whom also chewed gum regularly as a supplementary strategy and 5 (18 percent) of whom also used artificial saliva (Table 1). These results were comparable to the study by Morton et aI, 1997. The amount of water used was found to correlate with the XI score (correlation coefficient rho = 0.43, P = 0.012) and, similarly, there was a trend for those who used more Dentacal to be among the higher water users.

Other first-preferred strategies were: chewing gum (six patients, five of whom also sipped water frequently and two of whom also used artificial saliva); artificial saliva (two patients, both of whom also sipped water frequently). One patient used no moistener, preferring to "put up with the dryness".

In those patients who stated that chewing gum was their first preference, its efficacy rating was higher than that of water (the most popular option), but not significantly so. Interestingly, the XI score for this group ranged from 24-36 showing that the degree of "dryness" was not necessarily a factor in choosing a moistening strategy.

Thirty two patients (86 percent) said that Dentacal, as used in the study in an atomiser bottle, was more convenient to use than the way they used their usual mouth moistener. Of the 5 who thought otherwise, one patient, who had a high XI score of 36, stated that additional water was required as the atomiser did not provide enough material conveniently. The other four patients had lower XI scores ranging between 19 and 28.

Thirty out of 36 subjects (83 percent) who responded to the question as to how Dentacal compared with their usual methods of moistening the mouth felt that Dentacal was at least the Same (10, or 28 percent) or better (20, or 55 percent) (Table ll).

Table Ill shows that the mean "usefulness" rating of Dentacal was about 6 (median score, 7), on a scale of 0-10. This lay between the average scores for the most useful and the second best ("less useful") strategies normally used by the study group.

There was no statistical correlation between the XI score and the effectiveness-rating of Dentacal compared to the usual mouth moisteners or, indeed, whether using Dentacal was preferred to the usual moistening strategies. Nor were the degree of dysphagia, difficulty with speaking, sore mouth or throat, or taste-disturbance correlated with whether Dentacal was considered more effective than or preferable to their usual mouth moistener. The cause of xerostomia did not correlate with the perceived duration of effect of Dentacal (Table IV).

The majority of patients (71 percent) used up to 25ml of Dentacal per day, with 27 percent using up to 50ml (Table V). This was a large reduction on the daily volume of water (average 1200ml/day/patient) normally used for moistening purposes. However, Dentacal using the atomiser as the sole strategy did not adequately moisten the throat or mouth in 14 of 23 patients who had an XI score greater than 26 (range 26-45). Nevertheless, six patients specifically reported that the Dentacal enabled them to sleep for longer periods without being woken by the xerostomia, compared to their usual strategy.

To the question "Dentacal has been shown to significantly reduce dental decay when used as a mouth rinse 3 times per day. Would you therefore use it in preference to your usual mouth moistener?", thirty four patients (92 percent) affirmed that they would do so. Three respondents would not preferentially use Dentacal; giving-the following as their reasons: a drying sensation, a slightly burning sensation in the throat, the development of a stale taste.

None of the respondents indicated that Dentacal was not refreshing.

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DISCUSSION

The present study has shown that Dentacal was evaluated favourably by the majority of people who used it in the manner described and that the flavour was acceptable, with many patients admitting that it was refreshing.

A small proportion of subjects with extreme xerostomia felt that although the method using the "atomiser" dealt satisfactorily with dryness in the mouth, there was a need also to sip additional water because of throat dryness. They agreed that this difficulty could probably be overcome by using a "pump" dispenser which would deliver a larger volume of material per stroke.

Normally, most people with symptomatic xerostomia resort to frequently sipping water to overcome the problem of constant mucosal dryness in the oro-pharynx because it is cheap and there area variety of convenient self-sealing containers available that can be easily carried by the patient. However, even though water can keep the oral cavity wet, it is a poor lubricant, and many patients confirm that, paradoxically, it has a drying sensation when used as a moistener. Most patients indirectly indicated that Dentacal provided good lubrication in that an application of Dentacal lasted longer than their usual moistener before having to be repeated. Indeed, patients frequently complain bitterly about nocturnal xerostomia that may wake them every hour or two during the night and require the use of regular I moisteners. Comments indicated that the use of Dentacal I enabled longer periods of undisturbed sleep.

Although for many patients Dentacal was perceived to be providing better lubracation than their usual strategy, its qualities may be able to be improved further by the addition of other muco-simulatory materials. Whatever the developments in this area, our results here and previously (Morton et aI, 1997) would suggest that most patients will continue to use more than one strategy to maintain oral comfort.

There are several commercial products which attempt to mimic the function and constituents of natural saliva, for example, Luborant (Antigen/Baxter, Auckland, NZ); Salube (Orion Laboratories, Welshpool, Western Australia); Oral Balance (Laclede, Rancho Dominguez, California, USA), but patients often report that the material has a greasy texture, or a poor flavour or is too expensive, and few persist with these products. Where there is some salivary function, sugar-free chewing gums can be useful mechanical sialogogues. The parasympathomimetic sialogogue pilocarpine can also be helpful although the side effects of nausea, sweating and diarrhoea may be unacceptable. In dentate patients with xerostomia there is the additional and serious problem of increased dental caries, and none of these other products aim to attempt to remineralise the dentition in the xerostomia situation.

The outcome of this and the previous study (Hay and Thomson, 2002) using CD-CP therefore confirms that the material has both anti-caries efficacy and satisfactory mouth moistening properties when used regularly in dentate xerostomic patients. Such Potential benefits need to be explored, now that acceptability of this type of product has been established.

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ACKNOWLEDGEMENTS

NSI Pty Limited are thanked for providing the materials used in this study.

Nether of the authors has any commercial links with NSI Ply Limited, nor any personal financial interest in the outcome of this research.

REFERENCES

Bjordal K and Kaasa S (1995). Psychological distress in head and neck cancer patients 7-11 years after curative treatment. British Journal of Cancer 71: 592-597.

Hay KD, Morton RP, and Wall CR (2001). Quality of life and nutritional studies inpatients with xerostomia. New Zealand Dental Journal 97: 128.131.

Hay KD, and Thomson WM (2002). A clinical trial of the anti-canes efficacy of casein derivatives complexed with calcium phosphate. Oral Surgery, Oral Medicine, Oral Pathology, Oral RadIology, and Endodontics 93: 271-275.

Hay KD and Gear KJ (2002). Xerostomia and you. New Zealand Dental Journal 98: 46-51.

Morton RP, Hay KD. and North R (1997). Xerostomia. Symptoms, sequelae and management. Patient Management 26/7: 11-13.

Thomson WM. Chalmers JM, Spencer AJ, and Williams SM (1999). The Xerostomia Inventory: a multi-item approach to measuring dry mouth. Community Dental Health 16: 12-17.

Thomson .WM and Williams SM (2000). Further testing of the Xerostomia Inventory. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics 89: 46-50.

KD HAY, BDS, FDSRCS, MDSc
Oral Health Unit,
Green Lane Hospital,
Green Lane,
Auckland,
New Zealand

RP MORTON, MBBS, MSc, FRACS
Dept of Otolaryngology,
Green Lane Hospital,
Green Lane,
Auckland,
New Zealand

Corresponding author: David Hay
(E-maiI: dhay@ahsl.co.nz)

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