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Studies on masticatory efficiency
STUDIES
ON MSSTICATORII. REVIEW
REIDAR
F.
EFFICIENCY”
OF LITERATVRF,
XOGNNAES,
N.
ROCHESTER,
P.
T
HE following work started from the observation that undigested corn particles appeared in the feces of rats fed a caries-producing diet containing 60 per cent coarse corn particles. Since these particles were almost the size of a rat molar, it seemed possible that a decreased masticatory efficiency might be partly responsible for the complex chain of events ending in destruction of the teeth. In surveying the literature, no studies were found on the masticatory efficiency of animals. However, some workers have shown an interest in the masticatory efficiency of humans and its significance. It is of interest, therefore, to review some of these studies before proceeding to rat experiments. The degree to which an individual masticates the food depends on many factors, such as the function of the masticator)- muscles, the number of chewOne cannot ing movements, number and condition of teeth, and biting strength. predict the masticator- efficiency by examination of one of these factors alone. If, for example, all the molars of the mandible have been lost, then the masticatory efficiency would be infinitely reduced in spite of the presence of four-fifths of the total number of teeth. Neither does the biting strength necessarily reflect the degree to which a person is able to, or chooses to, masticate the food. The following review has therefore been limited to actual studies of the degree of food distintcgration or partition durin, 0~mastication, and the significance of the teeth as part of the gastrointestinal tract, in promoting digestion and utilization of food. Lehmann (19OO)l and Gaudenz (1901),” two Swiss workers, appear to be among the first to make observations on mast,icatory efficiency. They tested the degree t,o which they masticated various types of food, beef, macaroni, potato, and raw apple, proceedin, v with the mastication until they noticed the desire to swallow. When feeling that the reflex of the deglutination was about to occur, the mouth was emptied and the particle size of the masticated food examined. Ilehman found that the food was either in solution or in particles less than 2 mm. in diameter. Extending the work, Gaudenz found that when biting off a piece of common food with the incisor teeth, the average size of the b&e which he felt suitable to carry on to mastication was about 5 em. in length, varying from 3.6 to 6.8 Gm. for various types of food, macaroni, egg, meat, Following cheese, vegetable, fruit, and bread. mastication with the molar teeth, he emptied the contents of his mouth on a sieve with 1 mm. openings. The particles left on top of the sieve were then separated into various sizes and those passing through the sieve were examined under the microscope. For studies of the particle size, he found that macaroni and egg white were best The suited, and noticed that many particles were as much as ‘i mm. in diameter. of
From Rochester, *This
The Division of Dental Rochester, N. Y. work was supported by
Research, a grant
School from 309
the
of
Medicine
Carnegie
and
Corporation
Dentistry, of New
University York.
Reidar F.
310
Xognnaes
coarsest particles observed had a maximum diameter of 12 mm. while the minimum part.icle size was .Ol mm. Van Oefele (1901-1905)” reported observations made on feces of patients who, because of reduced number of teeth, were unable to masticate their food properly. In cases where the molar teeth had been lost, he found that the feces contained undigested starch and believed this to be caused by insufficient mastication, with resulting lack in salivary secretion. But, as pointed out by later workers, his evidence was not quite satisfactory enough to permit any definite conclusions. In his popular book on the A.B.-Z. of nutrition Horace Fletcher” considers the mastication of food as one of the most important factors in digestion. This conclusion is based on his personal experiences as well as on the other observations which he reviews, including the philosophic writings of Campbell,t appearing in the Lalnicet the same year (1903). Hornborg (1904)” observed an increase in gastric secretion in a child with gastric fistula during mastication of agreeable foods. Cohnheim (1908) ’ compared the gastric digestion and evacuation time of the stomach following meals of finely and coarsely ground meat fed to dogs with duodenal fistula. The stomach responded by delayed gastric evacuation and increased protein digestion when receiving the coarse meat particles, while the finely ground meat was rapidly evacuated and thus less digested in the stomach. Similarly, Euler (1908) ,G by examining his own gastric content following ingestion of finely and coarsely ground meat, found that the finely ground meat reduced the gastric evacuation time. There are only a few and mostly contradictory observations on the importance of mastication for the absorption and utilization of food, while several workers have studied the mechanical breakdown of food by the teeth. Rosenfeld (1916)8 tested the feces of a person following insufficient and sufficient mastication. Hc claimed that poorly masticated food resulted in an increased loss of nitrogen, fat and ash in the feces, but his procedures have been subjected to criticism. In addition more cases ought to have been studied. Two German workers, Paulsen (1920)” and Clausen (1921)’ studied the mechanical breakdown of food by examination of the masticated bolus. Paulsen first masticated normally and subsequently disturbed the occlusion of the teeth by means of artificial high crowns placed upon the mandibular first molars. Clausen, on the other hand, masticated first with his natural teeth, of which ten were missing, and subsequently with a partial artificial denture, as substitute for the missing teeth. Both workers found a decreased partition of the food when the masticatory function was impaired, either by the high artificial crowns However, they also observed that this or by removal of the partial denture. insufficient mastication could be partly overcome by prolonging the time of Similar observations were reported by Schiitz (1922)lO who also chewing. emphasized the compensation for poor dentition provided by prolonged mastiFurthermore he suggested that the stomach probably has the ability cation. to adjust itself to the coarseness of the food. *“The A.B.-Z. t”Obnervations
of Our own Nutrition,” F. A. on Mastication.” Lancet. July
Stokes Co.. New 11. 18, 25, and
York. Aunust
1903. 8. 1903.
An improvement in the technique for measurement of the masticatorJ efficiency was made by Christiansen (1923) .I1 He allowed pat,ients to masticate a certain amount of hazel nuts or cocoanut for a certain length of time, i.e., fifty masticatory movements. Then the patient emptied the mouth and thoroughlv rinsed it, placing the contents on the top of superimposed sieves of decreasing mesh, i.e., 2, 11/z, l/z and l/s mm. opening. When the masticated food had been washed through the sieves, the fraction on the top of each sieve was dried and weighed, and the percentage distribution determined. In this manner he compared the masticatory efficiency of normal, slightly defective, severely defective, and artificial teeth. As a method for testing masticatory effieicncy, this work is given credit by Bluntschli and Winkler (1927) ,I2 since it permitted a more accurate dctermination of the mechanical breakdown of food during mastication. But thr significance of t,he teeth in regard to utilization of food needed further invest,igntion. This question was taken up by another Scandinavian worker, Reeker (1927) .lS Working at a hospital in Helsingfors, he arranged to st,udp a 32year-old woman over a period of four months. A complete history of the subjcct indicated normal health conditions except for WI’!- defective teeth. She received ordinary food which did not require any extra degree of mastication and was allowed to chew as long as she desired before swallowing. Analyses were made on the excrcta, first during a period at the start of t,he experiment, second after the defective teeth had been removed and the wounds healed, and third after insertion of artificial teeth. TTndcr these three cslwrimental conditions, no marked difference was found in the degree of utilization. TSeckcl believed this could be explained first by the fact that modern food does not require a high degree of mastication, and second because the remaining part of the gastrointestinal tract in healthy individuals probably can compensate for lark of food partition in the oral cavity. One may, however, wonder tvhet,her the results indicate that very defective teeth, edentulous jaws, and newly inserted artificial teeth are equally efficient in masticating common foods. Nevertheless, later workers have brought some support for Becker‘s conclusions. Thus, scppii (1929) )I4 working in the same cit,v, examined the absorption of ordinary foods following poor? normal, and prolonged mastication. In most cases hc folmd that the absorption was about t,hc same. Only in the case of bacon was the Celman utilization considerably promoted by prolonging the mastication. (1932) )I> working in ~Ioscow-, came to similar conclusions. Thus, he found that, it made lit,tle differmcct whether the subjects masticated with or without dcntnres, if thcp divided the food only with the incisor teeth, or if they did not masticate the food at all. He made the rcscrvation, however, that this is probabl- true only if the rest of the gastrointestinal tract is in a healthy condition. Unaware of the method of Christiansen, mentioned before, Gelman (1933) I’; worked owt a similar but somewhat simpler procedure for the purpose of moasuring masticator>- efficiency. He made his subjects masticate 5 cm. of almonds for fifty seconds, and after dq-ing the masticated bolus, he determined t,he weight of t,he particles which were small enough to pass a sieve with 2.4 mm. openings. The masticator>- efficiency could then bc designated as the percentage of 5 Gm. which passed the sieve, bein g 300 per cent if all of the original 5 Gm. were divided into particles of less than 2.4 mm. in diameter.
Reich-
3 I%
F. Soynnaes
In summarizing, it may be said that the studies on masticatory efficiency just reviewed hare not been extensive enough, nor have they been sufficiently well controlled to allow any definite conclusions. The importance of mastication and fine partition of the food for salivary and gastric secretion, the digestion and the evacuation time of the stomach has been emphasized by some workers. But disagreement exists in observations on the utilization of food following mastication with dentitions of various degrees of efficiency. While some workers have shown that insufficient mastication is responsible for undigested food in the feces, the bulk of the evidence indicates t,hat the condition and number of t,hc teeth make no difference in the degree of food utilization, at least not so far as modern diets are concerned. However, such studies have been done on very few subjects, and since all were hman individuals without sufficient controls, individual variations have not been taken into account. Methods to measure the efficiency of the teeth in ma&eating food have been developed, but employed by only a few workers. With respect to the mechanical breakdown of the food during mastication, such work has tended to justify the maintenance of healthy teeth and replacement of lost t,eeth. But the importance of a complete dentition, natural or artificial, in promoting digestion and utilization of food, has not been adequately demonstrated. (To
BE COXTIr;r-FD.) REFERESCES
1. Lehmxm, K. R.: ibr die Zerkleinerung und Liisung der Speisen beim Kauen, Miincheu. med. Wchnsrhr. 47: 983, 1930. 2. Gautlenz, J. U.: Ueher die Zerkleinerung und Lijsung van Nahrungsmitteln beim Kauact, Arch. f. Hygiene 39: 230, 1901. 3. Van Oefele, F.: Mangelhaftcs Kauen und die Eigmwhaften de? Faeces, Deutsche Zahn. Wchnwhr., No. 32, 1901; No. 40, 41, 42, 1902 ; No. 17, 35, 36, 1904; No. 10, 12, 22, 1905. 4. Hornborg, A. F.: Beitrlge zur Kenntniss der Absonderungs-bedingungen des Magenshaftes beim Menschen, Scapd. Arch. f. Physiol. 15: 209, 1904. 3. Cohnheim, 0. : Die Physiologie der Vergauung und EmHhrung, Berlin, p. 22, 1907. 6. Euler, F.: Die Magenverdauung bei machineller Zerkleinerung des Fleisches, Deutwhe Zahu. Wchnschr., No. 7, 7908. 7. Rosenfeld, CT. : ZLhne und Verdauung, Reutschr Zahn. Wchnwhr., No. 34, 1916. 8. Paulsen : ic Ueber die Wirkung mangelhaftcr Kauf’ihigkeit auf die Verdauung, Dissertation, Kiel, 1920. 9. Clausen:* Die Rewertung drr Ziihne nach Kauenlreiten, gemessen durch Kauflache Druck untl Funktion. Dissertation. Kiel. 1921. 10. Schiitz, F. : Gebisk und Verda&g, its&r. f. Hyg. u. infektionskrankh. 45: 279, 1922. 11. Christiansen, E. G.: Einiee Untrrsuchungen iiber das KauvermBeen des natiirlirhen und kiinxtlichcn (:ebisses.c’~7rtlisclrr. f. Zxhn. 39: 1. 1923. I?. Bluntsrhli, H., and Winkler, tiR. : Kaubewegungen und Bissenbildung, Handbuch tlrr Sormalen und Patholog~schcu Physiologic. Vol. III, Verdauung und Verdauungsapparat, Julius Swinger, Berlin, p. 339. 1927. 1 ::. Becker, E:: Zur Ke\nt& ‘der Bede;tung ‘der ZBhne fur die Ausnutzung der Nahrungsnlittel im Verdauungs-apparat bei norm&r Secretion der Magendriisen, Stand. Arrlr. f. Physiol. 50: 283, 1927. 14. Se@, K.: Zur Kenntniss der Bcdeutung des Kauens fiir die Resorption, &and. Arch. f. Physiol. 57: 159, 1929. 15. Gelman, 8. E.: Die Bedeutung des Kauaktes-fur die Verdauung, Ztschr. f. Stomatol. 30: 957, 1932. 16. Gelman, S. E.: Die Kaufunktionsprobe, Ztschr. f. Stomatol. 31: 866 and 922, 1933. *Quoted
from
SePPB
(14).
ON MSSTICATORII. REVIEW
REIDAR
F.
EFFICIENCY”
OF LITERATVRF,
XOGNNAES,
N.
ROCHESTER,
P.
T
HE following work started from the observation that undigested corn particles appeared in the feces of rats fed a caries-producing diet containing 60 per cent coarse corn particles. Since these particles were almost the size of a rat molar, it seemed possible that a decreased masticatory efficiency might be partly responsible for the complex chain of events ending in destruction of the teeth. In surveying the literature, no studies were found on the masticatory efficiency of animals. However, some workers have shown an interest in the masticatory efficiency of humans and its significance. It is of interest, therefore, to review some of these studies before proceeding to rat experiments. The degree to which an individual masticates the food depends on many factors, such as the function of the masticator)- muscles, the number of chewOne cannot ing movements, number and condition of teeth, and biting strength. predict the masticator- efficiency by examination of one of these factors alone. If, for example, all the molars of the mandible have been lost, then the masticatory efficiency would be infinitely reduced in spite of the presence of four-fifths of the total number of teeth. Neither does the biting strength necessarily reflect the degree to which a person is able to, or chooses to, masticate the food. The following review has therefore been limited to actual studies of the degree of food distintcgration or partition durin, 0~mastication, and the significance of the teeth as part of the gastrointestinal tract, in promoting digestion and utilization of food. Lehmann (19OO)l and Gaudenz (1901),” two Swiss workers, appear to be among the first to make observations on mast,icatory efficiency. They tested the degree t,o which they masticated various types of food, beef, macaroni, potato, and raw apple, proceedin, v with the mastication until they noticed the desire to swallow. When feeling that the reflex of the deglutination was about to occur, the mouth was emptied and the particle size of the masticated food examined. Ilehman found that the food was either in solution or in particles less than 2 mm. in diameter. Extending the work, Gaudenz found that when biting off a piece of common food with the incisor teeth, the average size of the b&e which he felt suitable to carry on to mastication was about 5 em. in length, varying from 3.6 to 6.8 Gm. for various types of food, macaroni, egg, meat, Following cheese, vegetable, fruit, and bread. mastication with the molar teeth, he emptied the contents of his mouth on a sieve with 1 mm. openings. The particles left on top of the sieve were then separated into various sizes and those passing through the sieve were examined under the microscope. For studies of the particle size, he found that macaroni and egg white were best The suited, and noticed that many particles were as much as ‘i mm. in diameter. of
From Rochester, *This
The Division of Dental Rochester, N. Y. work was supported by
Research, a grant
School from 309
the
of
Medicine
Carnegie
and
Corporation
Dentistry, of New
University York.
Reidar F.
310
Xognnaes
coarsest particles observed had a maximum diameter of 12 mm. while the minimum part.icle size was .Ol mm. Van Oefele (1901-1905)” reported observations made on feces of patients who, because of reduced number of teeth, were unable to masticate their food properly. In cases where the molar teeth had been lost, he found that the feces contained undigested starch and believed this to be caused by insufficient mastication, with resulting lack in salivary secretion. But, as pointed out by later workers, his evidence was not quite satisfactory enough to permit any definite conclusions. In his popular book on the A.B.-Z. of nutrition Horace Fletcher” considers the mastication of food as one of the most important factors in digestion. This conclusion is based on his personal experiences as well as on the other observations which he reviews, including the philosophic writings of Campbell,t appearing in the Lalnicet the same year (1903). Hornborg (1904)” observed an increase in gastric secretion in a child with gastric fistula during mastication of agreeable foods. Cohnheim (1908) ’ compared the gastric digestion and evacuation time of the stomach following meals of finely and coarsely ground meat fed to dogs with duodenal fistula. The stomach responded by delayed gastric evacuation and increased protein digestion when receiving the coarse meat particles, while the finely ground meat was rapidly evacuated and thus less digested in the stomach. Similarly, Euler (1908) ,G by examining his own gastric content following ingestion of finely and coarsely ground meat, found that the finely ground meat reduced the gastric evacuation time. There are only a few and mostly contradictory observations on the importance of mastication for the absorption and utilization of food, while several workers have studied the mechanical breakdown of food by the teeth. Rosenfeld (1916)8 tested the feces of a person following insufficient and sufficient mastication. Hc claimed that poorly masticated food resulted in an increased loss of nitrogen, fat and ash in the feces, but his procedures have been subjected to criticism. In addition more cases ought to have been studied. Two German workers, Paulsen (1920)” and Clausen (1921)’ studied the mechanical breakdown of food by examination of the masticated bolus. Paulsen first masticated normally and subsequently disturbed the occlusion of the teeth by means of artificial high crowns placed upon the mandibular first molars. Clausen, on the other hand, masticated first with his natural teeth, of which ten were missing, and subsequently with a partial artificial denture, as substitute for the missing teeth. Both workers found a decreased partition of the food when the masticatory function was impaired, either by the high artificial crowns However, they also observed that this or by removal of the partial denture. insufficient mastication could be partly overcome by prolonging the time of Similar observations were reported by Schiitz (1922)lO who also chewing. emphasized the compensation for poor dentition provided by prolonged mastiFurthermore he suggested that the stomach probably has the ability cation. to adjust itself to the coarseness of the food. *“The A.B.-Z. t”Obnervations
of Our own Nutrition,” F. A. on Mastication.” Lancet. July
Stokes Co.. New 11. 18, 25, and
York. Aunust
1903. 8. 1903.
An improvement in the technique for measurement of the masticatorJ efficiency was made by Christiansen (1923) .I1 He allowed pat,ients to masticate a certain amount of hazel nuts or cocoanut for a certain length of time, i.e., fifty masticatory movements. Then the patient emptied the mouth and thoroughlv rinsed it, placing the contents on the top of superimposed sieves of decreasing mesh, i.e., 2, 11/z, l/z and l/s mm. opening. When the masticated food had been washed through the sieves, the fraction on the top of each sieve was dried and weighed, and the percentage distribution determined. In this manner he compared the masticatory efficiency of normal, slightly defective, severely defective, and artificial teeth. As a method for testing masticatory effieicncy, this work is given credit by Bluntschli and Winkler (1927) ,I2 since it permitted a more accurate dctermination of the mechanical breakdown of food during mastication. But thr significance of t,he teeth in regard to utilization of food needed further invest,igntion. This question was taken up by another Scandinavian worker, Reeker (1927) .lS Working at a hospital in Helsingfors, he arranged to st,udp a 32year-old woman over a period of four months. A complete history of the subjcct indicated normal health conditions except for WI’!- defective teeth. She received ordinary food which did not require any extra degree of mastication and was allowed to chew as long as she desired before swallowing. Analyses were made on the excrcta, first during a period at the start of t,he experiment, second after the defective teeth had been removed and the wounds healed, and third after insertion of artificial teeth. TTndcr these three cslwrimental conditions, no marked difference was found in the degree of utilization. TSeckcl believed this could be explained first by the fact that modern food does not require a high degree of mastication, and second because the remaining part of the gastrointestinal tract in healthy individuals probably can compensate for lark of food partition in the oral cavity. One may, however, wonder tvhet,her the results indicate that very defective teeth, edentulous jaws, and newly inserted artificial teeth are equally efficient in masticating common foods. Nevertheless, later workers have brought some support for Becker‘s conclusions. Thus, scppii (1929) )I4 working in the same cit,v, examined the absorption of ordinary foods following poor? normal, and prolonged mastication. In most cases hc folmd that the absorption was about t,hc same. Only in the case of bacon was the Celman utilization considerably promoted by prolonging the mastication. (1932) )I> working in ~Ioscow-, came to similar conclusions. Thus, he found that, it made lit,tle differmcct whether the subjects masticated with or without dcntnres, if thcp divided the food only with the incisor teeth, or if they did not masticate the food at all. He made the rcscrvation, however, that this is probabl- true only if the rest of the gastrointestinal tract is in a healthy condition. Unaware of the method of Christiansen, mentioned before, Gelman (1933) I’; worked owt a similar but somewhat simpler procedure for the purpose of moasuring masticator>- efficiency. He made his subjects masticate 5 cm. of almonds for fifty seconds, and after dq-ing the masticated bolus, he determined t,he weight of t,he particles which were small enough to pass a sieve with 2.4 mm. openings. The masticator>- efficiency could then bc designated as the percentage of 5 Gm. which passed the sieve, bein g 300 per cent if all of the original 5 Gm. were divided into particles of less than 2.4 mm. in diameter.
Reich-
3 I%
F. Soynnaes
In summarizing, it may be said that the studies on masticatory efficiency just reviewed hare not been extensive enough, nor have they been sufficiently well controlled to allow any definite conclusions. The importance of mastication and fine partition of the food for salivary and gastric secretion, the digestion and the evacuation time of the stomach has been emphasized by some workers. But disagreement exists in observations on the utilization of food following mastication with dentitions of various degrees of efficiency. While some workers have shown that insufficient mastication is responsible for undigested food in the feces, the bulk of the evidence indicates t,hat the condition and number of t,hc teeth make no difference in the degree of food utilization, at least not so far as modern diets are concerned. However, such studies have been done on very few subjects, and since all were hman individuals without sufficient controls, individual variations have not been taken into account. Methods to measure the efficiency of the teeth in ma&eating food have been developed, but employed by only a few workers. With respect to the mechanical breakdown of the food during mastication, such work has tended to justify the maintenance of healthy teeth and replacement of lost t,eeth. But the importance of a complete dentition, natural or artificial, in promoting digestion and utilization of food, has not been adequately demonstrated. (To
BE COXTIr;r-FD.) REFERESCES
1. Lehmxm, K. R.: ibr die Zerkleinerung und Liisung der Speisen beim Kauen, Miincheu. med. Wchnsrhr. 47: 983, 1930. 2. Gautlenz, J. U.: Ueher die Zerkleinerung und Lijsung van Nahrungsmitteln beim Kauact, Arch. f. Hygiene 39: 230, 1901. 3. Van Oefele, F.: Mangelhaftcs Kauen und die Eigmwhaften de? Faeces, Deutsche Zahn. Wchnwhr., No. 32, 1901; No. 40, 41, 42, 1902 ; No. 17, 35, 36, 1904; No. 10, 12, 22, 1905. 4. Hornborg, A. F.: Beitrlge zur Kenntniss der Absonderungs-bedingungen des Magenshaftes beim Menschen, Scapd. Arch. f. Physiol. 15: 209, 1904. 3. Cohnheim, 0. : Die Physiologie der Vergauung und EmHhrung, Berlin, p. 22, 1907. 6. Euler, F.: Die Magenverdauung bei machineller Zerkleinerung des Fleisches, Deutwhe Zahu. Wchnschr., No. 7, 7908. 7. Rosenfeld, CT. : ZLhne und Verdauung, Reutschr Zahn. Wchnwhr., No. 34, 1916. 8. Paulsen : ic Ueber die Wirkung mangelhaftcr Kauf’ihigkeit auf die Verdauung, Dissertation, Kiel, 1920. 9. Clausen:* Die Rewertung drr Ziihne nach Kauenlreiten, gemessen durch Kauflache Druck untl Funktion. Dissertation. Kiel. 1921. 10. Schiitz, F. : Gebisk und Verda&g, its&r. f. Hyg. u. infektionskrankh. 45: 279, 1922. 11. Christiansen, E. G.: Einiee Untrrsuchungen iiber das KauvermBeen des natiirlirhen und kiinxtlichcn (:ebisses.c’~7rtlisclrr. f. Zxhn. 39: 1. 1923. I?. Bluntsrhli, H., and Winkler, tiR. : Kaubewegungen und Bissenbildung, Handbuch tlrr Sormalen und Patholog~schcu Physiologic. Vol. III, Verdauung und Verdauungsapparat, Julius Swinger, Berlin, p. 339. 1927. 1 ::. Becker, E:: Zur Ke\nt& ‘der Bede;tung ‘der ZBhne fur die Ausnutzung der Nahrungsnlittel im Verdauungs-apparat bei norm&r Secretion der Magendriisen, Stand. Arrlr. f. Physiol. 50: 283, 1927. 14. Se@, K.: Zur Kenntniss der Bcdeutung des Kauens fiir die Resorption, &and. Arch. f. Physiol. 57: 159, 1929. 15. Gelman, 8. E.: Die Bedeutung des Kauaktes-fur die Verdauung, Ztschr. f. Stomatol. 30: 957, 1932. 16. Gelman, S. E.: Die Kaufunktionsprobe, Ztschr. f. Stomatol. 31: 866 and 922, 1933. *Quoted
from
SePPB
(14).