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Recent and Current Research in Pedodontics
REVIEW O F 1958 DENTAL RESEARCH . . . V O LU M E 58, M AY 1959 • 33
37. Rosenthal, S. L. A n evaluation o f Ka sde no l (C lo rpa c tln ). J .A .D .A . 56:692 M a y 1958. 38. Bennett, D. T. The con ta m ina tion o f anesthetic needles. J. D. Res. 37:144 Feb. 1958. 39. Bender, 1. B.; Pressman, R. S., and Tashm an, G . C o m p a ra tiv e effects of local and system ic a n tib io tic the ra p y In the prevention o f postextraction bacterem ia. J.A .D .A . 57:54 Ju ly 1958. 40. Ingle, J. I., a nd Z eidow , B, J. A n e valuation of m echanical instrum entation a n d the n e ga tive culture in e n d o d o n tic therapy. J .A .D .A . 57:471 O c t. 1958.
41. Streltfield, M . M., a n d Zînner, D. D. M ic r o b io lo g ic hazards o f local d e nta l anesthesia. II. Pilot study o f involuntary a sp ira tio n o f b acteria into h y p o d e rm ic needles a nd anesthetic c a rtrid g e s after Injection. J .A .D .A . 57:657 N o v . 1958. 42. G lasser, M . M . B a c te rio lo g ic control in e n do dontlcs. O r a l Surg., O ra l M e d . & O r a l Path. 11:1278 N o v . 1958. 43. Sim s, W . A p ilo t study of a se ro lo g ic facto r In pe riod on ta l disease. O ra l Surg., O r a l M e d . & O ra l Path. 11:721 Ju ly 1958.
R E G E N T A N D C U R R E N T R E S E A R C H IN P E D O D O N T IC S
N orm a n H . O l s e n * D .D .S ., M .S .D ., C h ica go
Considering that the specialty o f pedodontics encompassess all facets o f den tistry limited to a specific age, it is quite difficult to determine objectively the limitations or scope o f research activity that should be included in or excluded from a report o f this type to the members o f the profession. A sincere appreciation is extended to the department chairmen o f the various dental schools and others who have assisted the author’ s endeavors in this interesting task. Th e observation has been made that there is a need for greater research activity in pedodontics by some of the dental schools as most of the recent contributions to research are emanating from only a limited number o f sources. A serial study conducted at the dental clinic o f the University of M ilan, Italy ,1 on the development o f the masticatory apparatus in fetuses and newborn infants has disclosed a couple o f rather interest ing observations. Initially, in infants seven months o f age who had been fed artificially for a period o f three months there was no disturbance in the develop ment of the masticatory apparatus. Second, normal eruption o f the deciduous teeth in thqir correct position was ob served in the majority o f infants who had not been fed by breast or bottle, and who
were thus without the functional stimulus which has been claimed by some essential for normal development of the mastica tory apparatus. Another interesting study conducted abroad was on the prevalence of enamel hypoplasia among children who had suf fered from gastrointestinal disease at one time or another during the period from birth to two years o f age .2 Thirty-two of 141 children, 22.7 per cent, showed evi dence of enamel hypoplasia. Th e coinci dence between the assumed period o f the occurrence o f enamel hypoplasia and the known period of gastrointestinal disease was found in 81.2 per cent of the chil dren examined. In a control group o f 124 children, chosen at random, who had no known incidence of gastrointestinal dis turbance during this period, the incidence of enamel hypoplasia was 15.3 per cent. There are probably as many different theories on the etiology and correct mode of therapy on thumb and finger sucking as there are authors who express their views. However, it is felt that an excel lent report of a study o f 2,650 infants and children selected in consecutive order from a general pediatric practice was given in the M ay, 1958, issue of the J ou r nal o f P ed ia trics .3 O f the 2,650 patients utilized in the study, 1,208, or 45.6 per
34 • THE J O U R N A L O F THE A M E R IC A N DENTAL A S S O C IA T IO N
cent, were thumb or finger suckers; the sex distribution was not statistically sig nificant. Seventy-five per cent o f the youngsters commenced sucking their finger during the first year. M ode o f feed ing, whether bottle or breast fed, did not seem to be o f any significance. However, the time period required for feeding did seem to be significant. T h e smallest per centage of those youngsters who sucked. their finger were in a group considered to be “ very slow feeders,” requiring 60 minutes or longer to eat. O f the “ fast feeders” (30 minutes or less to f e e d ), 45.8 per cent sucked their finger. In the group requiring 30 to 60 minutes to eat, 62.7 per cent had a finger habit. T h e average age at which all signs of finger sucking stopped was 3.8 years. Malocclusion oc curred in 7.9 per cent of the entire group included in the study. O f these children where malocclusion occurred, 55.4 per cent had sucked their finger at some time during their life. In the group o f 1,208 youngsters who were known thumb-suckers, 9.7 per cent developed malocclusion. Th ey also found no statistically significant relation between psychological problems and thumbsucking. It is quite interesting and significant to the members o f the profession when variations were observed from basic con cepts that have been accepted for years. Lynch ,4 in his study o f the occlusal sur face anatomy o f the human deciduous molar teeth, has presented data which are not representative o f that found in most text books o f dental anatomy. O f the variations he observed probably the most significant is the incidence o f sec ondary cusps: the mandibular first and second deciduous molars having three or four secondary cusps, the maxillary first molar having four or five secondary cusps, and the maxillary second molar with five or six cusps. A biometric study5 o f the effect o f pre mature loss o f deciduous teeth on the permanent dentition disclosed several in teresting points. A group of 41 children
who had lost 141 deciduous teeth, either by extraction or accident, comprised the source of information. It was concluded that there was less space lost by the ex traction o f the first deciduous molar than by extraction of the second deciduous molar. T h e highest rate o f space loss was observed in the upper permanent molars (between the second and third m olars). This is not in accordance with previous studies disclosing the greatest loss to oc cur in the mandibular second deciduous molar area. N o evidence was found to substantiate the theory that premature loss o f deciduous teeth produces displace ments of the midline or that it results in mesiopalatine rotation of the first per manent maxillary molars. It was interest ing to observe that the author concluded the rate of space loss was related not to the age o f the patient but to the number o f years elapsing after premature loss oc curred and the number of years likely to elapse before the bicuspids erupt. Th e contribution of Dorothy You ng 6 to the profession in providing a better understanding of ectopic eruption de serves more than a passing comment. O f 1,619 patients included in a study over a 14 year period, 52 patients exhibited 78 ectopic eruptions of the first permanent molar. T h e incidence o f this anomaly was much greater in the maxilla than in the mandible, and there appeared to be a higher incidence o f ectopic eruptions in the male sex. It was observed that 66 per cent of all ectopically erupting molars were in this locked position only temporarily and eventually jumped this locked position and erupted normally. Th e subject o f diet, and more specifi cally the correlation o f fermentable car bohydrates and their relation to dental caries, is a problem o f perennial interest. From a seven-day diet record o f 200 chil dren at the University o f Indiana ,7 the frequency o f eating was determined and the total sugar intake and the between meal sugar was calculated as to its car bohydrate equivalent in teaspoons of
REVIEW O F 1958 DENTAL RESEARCH . . . V O LU M E 58, M A Y 1959 • 35
sugar. Th e average total sugar intake was 164 teaspoons, whereas the average be tween meal sugar was 55 teaspoons. A slight negative relationship was obtained between the total sugar intake and the milk intake, indicating that as the milk intake tends to increase the sugar tends to decrease, and vice versa. A multiple correlation between D M F S and the total sugar and total milk intake showed a negative correlation coefficient. There is a great deal o f basic research in progress at the Isotope Laboratory at Hines Hospital,8'13 under the guidance o f M aury Massler. T h e utilization of radioisotopes has opened a new avenue in conducting clinical research that w ill con tribute immeasurably to an understanding of dental materials. Perhaps one o f the current projects o f most interest to the specialty o f pedodontics would be the in vestigations showing the marginal defects in amalgam fillings as revealed by radio iodine .14 This study suggests that perhaps it might be possible to produce a better restoration if the amalgam was placed into the tooth cavity in one homogeneous mass rather than the present practice of placing it in layers. Pulpal therapy for the deciduous and young permanent dentition continues to be one of the principal areas o f research activity in pedodontics. Th e affect of formocresol on the dental pulp and the use o f this agent in pulpotomy procedures is currently being investigated .15,16 It will be interesting to see what the clinical and histological data w ill demonstrate as to the effectiveness of this agent in pulpal therapy. Massler and Berman 17 amputated the pulps in 122 maxillary first molars in 61 male hooded rats. T h e medicaments used were calcium hydroxide and zinc oxide and eugenol; each medicament being placed in 61 teeth. Th e animals were sacrificed at intervals o f 7, 14, 21 and 28 days after the operation. T h e ob servations made were that the differences
in the pulpal reactions under calcium hydroxide and zinc oxide and eugenol could be observed at seven days after am putation, but by 21 days the histologic picture was approximately the same. It was concluded that calcium hydroxide was most essential to pulpal healing and bridging. However, calcium hydroxide caused a more rapid necrosis and degen eration of the superficial layer o f pulp tissue and a more rapid appearance of the primary calcific bridge. It has been felt that there is occasion ally an indication for a nonvital pulpot omy procedure, that is, in a very young child, a patient who will not accept local anesthesia or where the tooth is so badly broken down that asepsis cannot be main tained. T o substantiate the validity o f this procedure, W on g 18 studied the effects o f paraformaldehyde preparations on the periapical tissues in pulpotomy proce dures on nonvital teeth. Thirty-four teeth from four rhesus monkeys, aged 18 to 30 months, were included in the study. T h e average length o f time prior to sacrificing the animals after pulpotomy was per formed was 37 to 48 days for the per manent teeth, and 9 to 84 days for the deciduous teeth. Some of the more per tinent observations made were, initially, that the pulpal tissue o f both deciduous and permanent teeth have a similar re action when they come in direct contact with the paraform paste. This was a definite inflammatory reaction, round cell infiltration, hemorrhage, mucoid and hyaline degeneration, reticular atrophy and fibrosis. Second, new bone growing into the root canal through the apical foramen was observed only in treated permanent teeth. This phenomenon was not observed in treated deciduous teeth. Third, the rate o f root resorption of de ciduous teeth and rate o f root formation in the permanent teeth were not adversely affected. Finally, there was no internal resorption observed in any o f the treated deciduous or permanent teeth.
37. Rosenthal, S. L. A n evaluation o f Ka sde no l (C lo rpa c tln ). J .A .D .A . 56:692 M a y 1958. 38. Bennett, D. T. The con ta m ina tion o f anesthetic needles. J. D. Res. 37:144 Feb. 1958. 39. Bender, 1. B.; Pressman, R. S., and Tashm an, G . C o m p a ra tiv e effects of local and system ic a n tib io tic the ra p y In the prevention o f postextraction bacterem ia. J.A .D .A . 57:54 Ju ly 1958. 40. Ingle, J. I., a nd Z eidow , B, J. A n e valuation of m echanical instrum entation a n d the n e ga tive culture in e n d o d o n tic therapy. J .A .D .A . 57:471 O c t. 1958.
41. Streltfield, M . M., a n d Zînner, D. D. M ic r o b io lo g ic hazards o f local d e nta l anesthesia. II. Pilot study o f involuntary a sp ira tio n o f b acteria into h y p o d e rm ic needles a nd anesthetic c a rtrid g e s after Injection. J .A .D .A . 57:657 N o v . 1958. 42. G lasser, M . M . B a c te rio lo g ic control in e n do dontlcs. O r a l Surg., O ra l M e d . & O r a l Path. 11:1278 N o v . 1958. 43. Sim s, W . A p ilo t study of a se ro lo g ic facto r In pe riod on ta l disease. O ra l Surg., O r a l M e d . & O ra l Path. 11:721 Ju ly 1958.
R E G E N T A N D C U R R E N T R E S E A R C H IN P E D O D O N T IC S
N orm a n H . O l s e n * D .D .S ., M .S .D ., C h ica go
Considering that the specialty o f pedodontics encompassess all facets o f den tistry limited to a specific age, it is quite difficult to determine objectively the limitations or scope o f research activity that should be included in or excluded from a report o f this type to the members o f the profession. A sincere appreciation is extended to the department chairmen o f the various dental schools and others who have assisted the author’ s endeavors in this interesting task. Th e observation has been made that there is a need for greater research activity in pedodontics by some of the dental schools as most of the recent contributions to research are emanating from only a limited number o f sources. A serial study conducted at the dental clinic o f the University of M ilan, Italy ,1 on the development o f the masticatory apparatus in fetuses and newborn infants has disclosed a couple o f rather interest ing observations. Initially, in infants seven months o f age who had been fed artificially for a period o f three months there was no disturbance in the develop ment of the masticatory apparatus. Second, normal eruption o f the deciduous teeth in thqir correct position was ob served in the majority o f infants who had not been fed by breast or bottle, and who
were thus without the functional stimulus which has been claimed by some essential for normal development of the mastica tory apparatus. Another interesting study conducted abroad was on the prevalence of enamel hypoplasia among children who had suf fered from gastrointestinal disease at one time or another during the period from birth to two years o f age .2 Thirty-two of 141 children, 22.7 per cent, showed evi dence of enamel hypoplasia. Th e coinci dence between the assumed period o f the occurrence o f enamel hypoplasia and the known period of gastrointestinal disease was found in 81.2 per cent of the chil dren examined. In a control group o f 124 children, chosen at random, who had no known incidence of gastrointestinal dis turbance during this period, the incidence of enamel hypoplasia was 15.3 per cent. There are probably as many different theories on the etiology and correct mode of therapy on thumb and finger sucking as there are authors who express their views. However, it is felt that an excel lent report of a study o f 2,650 infants and children selected in consecutive order from a general pediatric practice was given in the M ay, 1958, issue of the J ou r nal o f P ed ia trics .3 O f the 2,650 patients utilized in the study, 1,208, or 45.6 per
34 • THE J O U R N A L O F THE A M E R IC A N DENTAL A S S O C IA T IO N
cent, were thumb or finger suckers; the sex distribution was not statistically sig nificant. Seventy-five per cent o f the youngsters commenced sucking their finger during the first year. M ode o f feed ing, whether bottle or breast fed, did not seem to be o f any significance. However, the time period required for feeding did seem to be significant. T h e smallest per centage of those youngsters who sucked. their finger were in a group considered to be “ very slow feeders,” requiring 60 minutes or longer to eat. O f the “ fast feeders” (30 minutes or less to f e e d ), 45.8 per cent sucked their finger. In the group requiring 30 to 60 minutes to eat, 62.7 per cent had a finger habit. T h e average age at which all signs of finger sucking stopped was 3.8 years. Malocclusion oc curred in 7.9 per cent of the entire group included in the study. O f these children where malocclusion occurred, 55.4 per cent had sucked their finger at some time during their life. In the group o f 1,208 youngsters who were known thumb-suckers, 9.7 per cent developed malocclusion. Th ey also found no statistically significant relation between psychological problems and thumbsucking. It is quite interesting and significant to the members o f the profession when variations were observed from basic con cepts that have been accepted for years. Lynch ,4 in his study o f the occlusal sur face anatomy o f the human deciduous molar teeth, has presented data which are not representative o f that found in most text books o f dental anatomy. O f the variations he observed probably the most significant is the incidence o f sec ondary cusps: the mandibular first and second deciduous molars having three or four secondary cusps, the maxillary first molar having four or five secondary cusps, and the maxillary second molar with five or six cusps. A biometric study5 o f the effect o f pre mature loss o f deciduous teeth on the permanent dentition disclosed several in teresting points. A group of 41 children
who had lost 141 deciduous teeth, either by extraction or accident, comprised the source of information. It was concluded that there was less space lost by the ex traction o f the first deciduous molar than by extraction of the second deciduous molar. T h e highest rate o f space loss was observed in the upper permanent molars (between the second and third m olars). This is not in accordance with previous studies disclosing the greatest loss to oc cur in the mandibular second deciduous molar area. N o evidence was found to substantiate the theory that premature loss o f deciduous teeth produces displace ments of the midline or that it results in mesiopalatine rotation of the first per manent maxillary molars. It was interest ing to observe that the author concluded the rate of space loss was related not to the age o f the patient but to the number o f years elapsing after premature loss oc curred and the number of years likely to elapse before the bicuspids erupt. Th e contribution of Dorothy You ng 6 to the profession in providing a better understanding of ectopic eruption de serves more than a passing comment. O f 1,619 patients included in a study over a 14 year period, 52 patients exhibited 78 ectopic eruptions of the first permanent molar. T h e incidence o f this anomaly was much greater in the maxilla than in the mandible, and there appeared to be a higher incidence o f ectopic eruptions in the male sex. It was observed that 66 per cent of all ectopically erupting molars were in this locked position only temporarily and eventually jumped this locked position and erupted normally. Th e subject o f diet, and more specifi cally the correlation o f fermentable car bohydrates and their relation to dental caries, is a problem o f perennial interest. From a seven-day diet record o f 200 chil dren at the University o f Indiana ,7 the frequency o f eating was determined and the total sugar intake and the between meal sugar was calculated as to its car bohydrate equivalent in teaspoons of
REVIEW O F 1958 DENTAL RESEARCH . . . V O LU M E 58, M A Y 1959 • 35
sugar. Th e average total sugar intake was 164 teaspoons, whereas the average be tween meal sugar was 55 teaspoons. A slight negative relationship was obtained between the total sugar intake and the milk intake, indicating that as the milk intake tends to increase the sugar tends to decrease, and vice versa. A multiple correlation between D M F S and the total sugar and total milk intake showed a negative correlation coefficient. There is a great deal o f basic research in progress at the Isotope Laboratory at Hines Hospital,8'13 under the guidance o f M aury Massler. T h e utilization of radioisotopes has opened a new avenue in conducting clinical research that w ill con tribute immeasurably to an understanding of dental materials. Perhaps one o f the current projects o f most interest to the specialty o f pedodontics would be the in vestigations showing the marginal defects in amalgam fillings as revealed by radio iodine .14 This study suggests that perhaps it might be possible to produce a better restoration if the amalgam was placed into the tooth cavity in one homogeneous mass rather than the present practice of placing it in layers. Pulpal therapy for the deciduous and young permanent dentition continues to be one of the principal areas o f research activity in pedodontics. Th e affect of formocresol on the dental pulp and the use o f this agent in pulpotomy procedures is currently being investigated .15,16 It will be interesting to see what the clinical and histological data w ill demonstrate as to the effectiveness of this agent in pulpal therapy. Massler and Berman 17 amputated the pulps in 122 maxillary first molars in 61 male hooded rats. T h e medicaments used were calcium hydroxide and zinc oxide and eugenol; each medicament being placed in 61 teeth. Th e animals were sacrificed at intervals o f 7, 14, 21 and 28 days after the operation. T h e ob servations made were that the differences
in the pulpal reactions under calcium hydroxide and zinc oxide and eugenol could be observed at seven days after am putation, but by 21 days the histologic picture was approximately the same. It was concluded that calcium hydroxide was most essential to pulpal healing and bridging. However, calcium hydroxide caused a more rapid necrosis and degen eration of the superficial layer o f pulp tissue and a more rapid appearance of the primary calcific bridge. It has been felt that there is occasion ally an indication for a nonvital pulpot omy procedure, that is, in a very young child, a patient who will not accept local anesthesia or where the tooth is so badly broken down that asepsis cannot be main tained. T o substantiate the validity o f this procedure, W on g 18 studied the effects o f paraformaldehyde preparations on the periapical tissues in pulpotomy proce dures on nonvital teeth. Thirty-four teeth from four rhesus monkeys, aged 18 to 30 months, were included in the study. T h e average length o f time prior to sacrificing the animals after pulpotomy was per formed was 37 to 48 days for the per manent teeth, and 9 to 84 days for the deciduous teeth. Some of the more per tinent observations made were, initially, that the pulpal tissue o f both deciduous and permanent teeth have a similar re action when they come in direct contact with the paraform paste. This was a definite inflammatory reaction, round cell infiltration, hemorrhage, mucoid and hyaline degeneration, reticular atrophy and fibrosis. Second, new bone growing into the root canal through the apical foramen was observed only in treated permanent teeth. This phenomenon was not observed in treated deciduous teeth. Third, the rate o f root resorption of de ciduous teeth and rate o f root formation in the permanent teeth were not adversely affected. Finally, there was no internal resorption observed in any o f the treated deciduous or permanent teeth.