A determination of the sensitivity of the dental pulp of primary maxillary anterior teeth to electrical stimuli in children with unilateral and bilateral clefts.

A study was conducted to determine differences in pulpal sensitivity of the maxillary primary anterior teeth in groups of children with unilateral clefts of the lip, alveolar process and palate, bilateral clefts of the lip process, and children without clefts. Thirty-nine children between the ages of 4 and 5 years with a total of 216 maxillary primary anterior teeth were tested using a pulp tester. The results indicated that maxillary primary anterior teeth distal to the cleft site are unaffected and demonstrate pulpal responses similar to the control group, while maxillary primary anterior teeth mesial to the cleft site are affected and demonstrate significantly less response to pulp testing compared to the control group. The results of this study are important for the clinician in establishing a proper diagnosis and treatment plan for children with clefts. The determination of the vitality of the dental pulp is a diagnostic adjunct in establishing the appropriate treatment for teeth in the primary dentition. A diagnosis is made based upon the integration of information derived from a history, clinical and radiographic examinations, and special diagnostic aids such as electric pulp testing. Neural impulse transmission has yet to be explained fully. Scott (1965), Yamada (1969), and Matthews (1970) attributed neural impulse transmission to the presence of dental receptors. The role of acetylcholinesterase in neural conduction has been investigated by Rapp et al. (1964). Other factors cited as being related to neural impulse transmission have been the hydrodynamic movement of tubular contents (Kramer 1955; Brannstrom 1963; Mumford and Newton 1964; Brannstrom and Astrom 1972) and the role of polypeptides as neural modulators in the pulp (Kroeger 1968). Electric pulp testers have been of value in suggesting the degree of sensitivity as an aid in determining the vitality of the dental pulp. Several variables, however, have been associated with electric pulp testing. These variables have been: (1) the use of unreliable or inaccurate instruments (Matthews and Searle 1974; Cooley and Robinson 1980); (2) unusual responses of individual teeth (Mumford 1959); (3) type of electrode media (Martin 1969); and (4) individual differences in clinical testing technique (Cooley and Robinson 1980). Reynolds (1966) used a standard electric pulp tester and electric thermal tooth stimulator to determine whether thermal testing could be of more specific diagnostic value. The teeth tested were examined radiographically, clinically, and later histologically. Thermal stimulus with the thermoelectric stimulator did not distinguish among normal, inflamed, or necrotic pulp as determined by the histologic findings. The electric vitalometer however demonstrated an accuracy of 100% in diagnosing vitality and nonvitality, but could not distinguish the specific state of vitality. The normal nerve distribution to the maxillary anterior teeth is derived directly from the filaments arising from the anterior superior alveolar nerve or from the superior dental plexus. The nasopalatine nerve may supplement innervation in the maxillary anterior region (Fischer 1933; Phillips and Maxmen 1941; Cook 1949; Olsen et al. 1955; Woodburne 1978; Basmajian 1980). Congenital orofacial clefts have been shown to alter the distribution of the nerves to the teeth adjacent to the cleft site (King 1954; Bohn 1963; McKinstry 1984). McKinstry found an elevated threshold of response to electrical stimuli of the permanent maxillary anterior teeth in patients with complete unilateral and bilateral Pediatric Dentistry: September, 1988 Volume 10, Number 3 215 clefts of the lip, alveolar process, and palate. The significance of this altered distribution in relationship to pulpal responsiveness of the primary teeth in children with clefts has yet to be determined. Performance of dental procedures such as the administration of local anesthesia, intracoronal restorations, crown preparations, and pulpal therapy requires a knowledge of the pulpal status of the teeth adjacent to unilateral and bilateral clefts. The purpose of this study was to determine whether differences existed in pulpal sensitivity to electrical stimuli: (1) between the primary maxillary anterior teeth among children with unilateral and bilateral complete clefts of the lip, alveolar process, and palate compared to those of noncleft children; (2) between central and lateral incisors of children with unilateral and bilateral complete clefts; and (3) between teeth the cleft side in unilateral complete clefts compared to those on the noncleft side and between teeth on the right side in bilateral complete clefts compared to those on the left side. Methods and Materials The final sample consisted of 39 children from the Cleft Palate Center and the Department of Pediatric Dentistry at the University of Pittsburgh. The criteria for inclusion were: .(1) the presence of sound and healthy primary maxillary anterior teeth (e.g., teeth free of caries, restorations, absence of mobility, abrasion, attrition or discoloration, and with no history of trauma); (2) absence of mental retardation; and (3) age ranging from 4 to 5 years so as to maintain appreciably similar root conditions related to the degree of root resorption (Knott and O’Meara 1967; Johnsen et al. 1979). The subjects were divided into 3 groups. Two experimental groups were established -one consisting of 15 children with unilateral clefts of the lip, alveolar process, and palate, and the other consisting of 10 children with bilateral clefts of the lip, alveolar process, and palate. The control group consisted of 14 noncleft children matched by age to the 2 experimental groups. Electric pulp tests were performed on 216 primary anterior teeth using a pulp tester (Model 2001 -Analytic Technology; Missoula, MT). To calibrate the instrument, the voltage and current output of the instrument were determined by the use of a voltmeter and Heathkit ® resistor. The determination was made by connecting the lead from the probe tester to the voltmeter. A second lead was connected from the resistor to the tip of the pulp tester. The voltage reading was read on the voltmeter and the resistance was calculated. The resistance was adjusted to 100,000 ohms. This resistance was reported by Jones (1969) to correspond closely the resistance of human enamel. The measurement of voltage and current at 100,000 ohms resistance was measured against the 50,000 ohms level to determine the consistency of the current output of the pulp tester. The sweep rate of the pulp tester was adjusted to the #6 setting to produce a moderate increase in intensity of electrical current with the minimum current output of about 150~tA. The teeth to be tested were isolated using cotton rolls and dried thoroughly using a compressed air syringe. The electrode tip of the pulp tester was dipped into a small amount of petroleum jelly to serve as an interface media between the tooth and the pulp tester. The amount of interface media utilized was a thin coating within the confines of the electrode tip. The electrode tip was applied flat onto the middle one-third of the crowns of the teeth tested in order to standardize the contact area and to maintain a uniform stimulus area throughout the study. The teeth were tested in a random order using the Latin Square method. Three responses were registered for each tooth tested. Lower readings of the pulp test responses were interpreted as a higher sensitivity to electrical stimuli and higher readings as lower sensitivity to electrical stimuli. A no-response reading was assigned when the digital display of the pulp tester demonstrated a value of >80. Prior to the actual experiment, a pilot study was conducted using the previously calibrated pulp tester to determine whether any differences in responses existed between the 4and 5-year-old children. Eight noncleft children, four aged 4 years and four aged 5 years, were utilized. The results indicated that there was sufficient variance among the 3 readings for each tooth on the 8 subjects, to suggest that the best method of data collection was to employ the mean value of the 3 readings. Also, no statistically significant differences were found in the pulp test responses between the 4and 5-year-old children; therefore, the 2 age groups were pooled for the actual study. The children were told that they were going to play a game to see what score they were going to receive as soon as their tooth tingled or began to feel warm. The tell-show-do method was used to introduce the pulp tester by showing the digital display as the light of the probe tip turned on upon touching the operator’s finger. The children were instructed to raise a hand at the first sensation of warmth or tingling in the tooth. The response level, as indicated on the digital display, was recorded for each tooth tested for the 3 study groups. To ensure that the child experienced a sensation from the electric pulp tester, a false positive test as described by Johnsen et al. (1979) was utilized. If the child responded during the false positive test, the entire procedure was started over. Children responding to a second 216 PULP TESTING IN UNILATERAL AND BILATERAL CLEFT CHILDREN: Abad Santos et al. false positive test were excluded from the study. This test was performed on each child for each tooth tested. As a result of congenitally missing teeth in the children with clefts, each tooth was considered as a dependent variable due to the variable number of teeth in each individual patient. To test whether there was a difference in pulpal sensitivity to electrical stimuli of the maxillary anterior teeth of children with unilateral or bilateral clefts and without clefts, an extension of the median test was performed. The null hypothesis that the 3 groups are from populations with the same median will be rejected if the calculated value is greater than the tabled critical value at the appropriate df(2) and the predetermined level of significance (.05). All of the statistical analyses utilized in the current study were based on that of Marascuilo and McSweeney (1977). The median test was utilized to determine whether there was a difference between central and lateral incisor pulpal sensitivity to electrical stimuli between children with unilateral clefts and those with bilateral clefts. To determine whether any pulpal sensitivity differences existed between contralateral pairs of maxillary anterior teeth among children with unilateral clefts, bilateral clefts, and those without clefts, the sign test was performed.