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Relationship of the Teeth to the Mandibular Canal and the Maxillary Sinus*
RELATIONSHIP OF THE TEETH TO THE M ANDIB' ULAR CANAL AND THE MAXILLARY SIN U S* By THESLE T. JOB, M.S., Ph.D., and RALPH H. FOUSER, B.S., D.D.S., Chicago, Illinois
V
A R IO U S studies have been made from time to time which involved the relationship o f the teeth to the m axillary sinus and the mandibular canal. A . Hopewell-Smith,1 Frederick B. Noyes,2 J. Parsons Schaeffer,'1 and Hugh W . M acM illian4 are a fe w o f the authors who have made valuable con tributions on the macroscopic relation ship o f the teeth to surrounding structures. Contributions on the minute anatomy o f these relationships seem to be notably lacking. It is therefore the aim to present here the results o f a study o f ♦From the Department o f Anatom y, Chi cago College o f Dental Surgery, Dental Department o f Loyola University. ♦Read before the Section on Exodontia, Anesthesia and Roentgenology at the Seventh International Dental Congress, Philadelphia, Pa., Aug. 24, 1926. 1. Hopewell-Smith, A .: An Introduction to Dental Anatom y and Physiology, Philadel phia, Lea & Febiger, 19 13 . 2. Noyes, F. B .: A Textbook o f Dental Histology and Em bryology, Philadelphia, Lea & Febiger, 19 2 1.
3.
Schaeffer, J. P .: Nose, Paranasal Sinuses, Nasolacrimal Passageways and O lfac tory Organ in M an, Philadelphia, P. Blakiston’s Son & Co., 1920. 4. M acM illan, H. W .: Dent. Soc., M ay, 1926. Jour. A .D . A., June, 1927
B ull.
Chicago
the minute anatomy o f the structures between the teeth and the m axillary sinus and the mandibular canal. Serial sections have been made in all three planes at different ages o f the human maxilla and mandible. As the material selected was from specimens with no evident pathologic condition in the mouth, it represents what is be lieved to be the normal anatomy. The illustrative material o f this paper is selected to show the average conditions found in the specimens studied. It should be mentioned that we re cognize the great variability in the num ber o f teeth related to the m axillary sinus, and the variability o f the relation ship o f the third molar to the mandibu lar canal, but these facts do not enter into the realm o f this paper, since it is only the minute anatomy o f the inter vening structures where the teeth are intimately related to the m axillary sinus and the mandibular canal that here con cerns us. M A X IL L A
A minute examination o f the tissues related to the m axillary sinus reveals a compact, laminated layer o f bone form ing the floor o f the sinus. This bony layer is notably thinner than the lingual 1072
Job-Fouser— Relationship o f the Teeth to the Mandibular Canal
and buccal plates o f the alveolar process (Figs. 1 and 3 ) . Furthermore, it is not a solid layer o f bone but frequently perforated by the soft tissues (Figs. 1 -4 ).
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cellous bone. T he ratio o f bone to medullary space in this area is worthy o f special attention. Figures 2 and 4 illustrate this point. It is evident that the
Fig. 1.— Frontal section o f m axilla, showing lingual root o f the first molar and the surrounding structures.
These perforations are, in the main, microscopic, and have a tortuous course through the bone. However, not infrequently, macroscopic foram ina are seen. Immediately below the floor o f the m axillary sinus is a narrow zone o f can-
area o f the medullary spaces is equal to, i f not greater than, the area o f the cancellous bone. The cancellous bone in this zone attaches directly the plate o f bone in the floor o f the maxillary sinus with the lamina dura o f the apices o f the roots o f the teeth. Below this
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The Journal o f the American Dental Association
thin zone o f cancellous hone and lying between the roots o f the teeth'is a large m edullary space (Figs. 1, 3 and 5 ) . In the plane o f the upper one h a lf o f the roots o f the molars, this medullary space
roots come in direct contact with the buccal and lingual plates o f the alveolar process. The perforations in the lamina dura vary greatly in size and number as well
Fig. 2.— Higher magnification o f root-end region shown in Figure 1.
is spacious. O nly rarely are plates o f cancellous bone found bridging this space from buccal to lingual plate (Fig. 5 ). The lamina dura is truly a much perforated layer o f compact, laminated bone, with a narrow zone o f cancellous bone associated with it except where the
as in position. There is also a difference between the maxilla and mandible in this respect, there being a strong tendency fo r a greater number o f openings to be present on the interproximal surfaces o f the roots o f the maxilla, while, in the mandible, the greater number o f openings are toward the mandibular
Job-F ouser— Relationship o f the Teeth to the Mandibular Canal
canal. This fact appears to be deter mined by the source o f the largest blood supply. P R A C T I C A L C O N S ID E R A T IO N
The anatomic facts just pointed out have direct bearing on the treatment o f
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o f the alveolae o f the teeth to this layer o f bone, and the definite attachment o f the lamina dura to the floor o f the m axillary sinus. In abscesses, the cribri form nature o f the lamina dura and the floor o f the m axillary sinus becomes
Fig. 3.— F rontal section o f m axilla, showing slight tangential cut o f the first m olar and surrounding structures.
these tissues and on the pathologic manifestations that are frequently found in this area. In curettage o f this area, one should always remember the thinness o f the layer o f bone form ing the floor o f the m axillary sinus, the close proximity
important. The direct continuity o f the soft tissues lining the maxillary sinus with the peridental membrane and the large medullary spaces, which is a constant anatomic fact (Figs. 2 and 4 ) , permits easy metastasis.
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The Journal o f the American Dental Association
In interpreting radiograms, the ir regular character and cribriform nature o f the lamina dura should be consid ered. Not infrequently, enlarged open ings are found in the lamina dura so located as to give the impression in radiograms o f resorption areas, when,
maxilla. The compact bone, which comprises the buccal, labial and lingual plates, is thicker (Fig. 7 ) ; the haversian type o f bone predominates in the alveolar plates. Cancellous bone is o f the same general character as that found in the maxilla, although the smaller
Fig. 4.— Higher magnification o f root-end region o f m olar, showing rela tionship to the m axillary sinus and surrounding structures.
as a matter o f fact, they are normal structures (Figs. 2 and 5 ) . These facts hold true, though in a less intimate way, with those teeth not so closely related to the m axillary sinus (Fig. 6 ) . M A N D IB L E
The mandible presents a somewhat different structural picture, yet the histologic features o f the bone are o f a similar character to those found in the
medullary spaces appear to be more numerous. The w all o f the mandibular or in ferior dental canal is composed o f a thin layer o f compact, laminated bone that is extensively perforated, especially on the surface toward the apices o f the teeth. It is surrounded throughout its course by cancellous bone. The canal is closely associated with the lingual plate (Fig. 8)
Job-F ouser— Relationship o f the Teeth to the Mandibular Canal
and continues forw ard to the region o f the bicuspids, where it turns laterally to the mental foramen. This foramen terminates the canal proper, but the in cisive branches o f the inferior alveolar structures continue through the cancel-
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mandibular canal. The second and first molars are slightly more distant, as are the bicuspids. P R A C T I C A L C O N S ID E R A T IO N
The general character o f the bony structures is much the same as in the
Fig. 5.— Horizontal section o f the m axilla, showing character o f the bone near the root ends o f the m olar teeth and immediately below the floor o f the m axillary sinus.
lous portion o f the bone, between the bony plates, to be distributed to the cuspid and incisor teeth. The third molar, owing to its position at or near the angle o f the mandible, bears the closest relationship to the
maxilla, except that, in the mandible, we have the root ends o f the teeth closely related to the mandibular canal. In the surgical treatment o f chronic dento-alveolar abscess, frequently the operator injures the structures contained
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The Journal o f the American Dental Association
in the canal. T he character o f the bone and the close promixity o f the root ends to the canal make such injury possible (Fig. 8 ).
the pathologic changes that take place in these regions. In the correct interpretation o f pathologic changes, it is not only necessary to understand the tissue manifestations but it is also essential to know the normal anatomy and rela tionships o f the areas. It is o f the utmost importance that the
Fig. 7.-— Frontal section o f mandible in the region o f the mesial root o f the first molar.
Fig. 6.— Frontal section o f m axilla through the region o f the second bicuspid ( le ft) . C O N C L U S IO N
A thorough knowledge and proper consideration o f the anatomic structures o f the maxilla and mandible are o f basic importance. T he structures under con sideration bear a direct relationship to
operator have an accurate knowledge o f the normal as w ell as the pathologic anatomy o f these parts, as proper sur gical intervention, when necessary, is based upon the scientific knowledge o f the anatomic, physiologic and pathologic character o f the parts. W e hope that this contribution may help bring about a more accurate un derstanding o f these basic factors and a
Job-F ouser— Relationship of the Teeth to the Mandibular Canal
more accurate interpretation o f the pathologic changes occurring in these areas, and may result in more scientific surgical treatment.
1079
lamina dura has been considered as certain a barrier against the exit o f micro-organisms as that dense layer o f tissue between the dentin and the cementum. This research discloses that the lamina dura, instead o f being a bar-
Fig. 8.— Higher magnification o f root-end region shown in Figure 7. Note the lingual plate o f compact bone; the mandibular canal and contents, and the apical region. DISCU SSION
Alonzo No dine, London, England: This annihilates another o f those fallacies with which the dental profession is obsessed. The fact that the lamina dura is intact has been considered, fo r some time, as indisputable p ro o f that the tooth is not only free from infection but even safe and savable. The
rier, is a sieve. The numerous channels shown in the slides as extending through this structure are conclusive and convincing evi dence o f this fact. The infection within the tooth m ay be conveyed beyond the tooth into the circulation by means o f these channels and infect any tissue or organ fo r which they have an affinity.
V
A R IO U S studies have been made from time to time which involved the relationship o f the teeth to the m axillary sinus and the mandibular canal. A . Hopewell-Smith,1 Frederick B. Noyes,2 J. Parsons Schaeffer,'1 and Hugh W . M acM illian4 are a fe w o f the authors who have made valuable con tributions on the macroscopic relation ship o f the teeth to surrounding structures. Contributions on the minute anatomy o f these relationships seem to be notably lacking. It is therefore the aim to present here the results o f a study o f ♦From the Department o f Anatom y, Chi cago College o f Dental Surgery, Dental Department o f Loyola University. ♦Read before the Section on Exodontia, Anesthesia and Roentgenology at the Seventh International Dental Congress, Philadelphia, Pa., Aug. 24, 1926. 1. Hopewell-Smith, A .: An Introduction to Dental Anatom y and Physiology, Philadel phia, Lea & Febiger, 19 13 . 2. Noyes, F. B .: A Textbook o f Dental Histology and Em bryology, Philadelphia, Lea & Febiger, 19 2 1.
3.
Schaeffer, J. P .: Nose, Paranasal Sinuses, Nasolacrimal Passageways and O lfac tory Organ in M an, Philadelphia, P. Blakiston’s Son & Co., 1920. 4. M acM illan, H. W .: Dent. Soc., M ay, 1926. Jour. A .D . A., June, 1927
B ull.
Chicago
the minute anatomy o f the structures between the teeth and the m axillary sinus and the mandibular canal. Serial sections have been made in all three planes at different ages o f the human maxilla and mandible. As the material selected was from specimens with no evident pathologic condition in the mouth, it represents what is be lieved to be the normal anatomy. The illustrative material o f this paper is selected to show the average conditions found in the specimens studied. It should be mentioned that we re cognize the great variability in the num ber o f teeth related to the m axillary sinus, and the variability o f the relation ship o f the third molar to the mandibu lar canal, but these facts do not enter into the realm o f this paper, since it is only the minute anatomy o f the inter vening structures where the teeth are intimately related to the m axillary sinus and the mandibular canal that here con cerns us. M A X IL L A
A minute examination o f the tissues related to the m axillary sinus reveals a compact, laminated layer o f bone form ing the floor o f the sinus. This bony layer is notably thinner than the lingual 1072
Job-Fouser— Relationship o f the Teeth to the Mandibular Canal
and buccal plates o f the alveolar process (Figs. 1 and 3 ) . Furthermore, it is not a solid layer o f bone but frequently perforated by the soft tissues (Figs. 1 -4 ).
1073
cellous bone. T he ratio o f bone to medullary space in this area is worthy o f special attention. Figures 2 and 4 illustrate this point. It is evident that the
Fig. 1.— Frontal section o f m axilla, showing lingual root o f the first molar and the surrounding structures.
These perforations are, in the main, microscopic, and have a tortuous course through the bone. However, not infrequently, macroscopic foram ina are seen. Immediately below the floor o f the m axillary sinus is a narrow zone o f can-
area o f the medullary spaces is equal to, i f not greater than, the area o f the cancellous bone. The cancellous bone in this zone attaches directly the plate o f bone in the floor o f the maxillary sinus with the lamina dura o f the apices o f the roots o f the teeth. Below this
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The Journal o f the American Dental Association
thin zone o f cancellous hone and lying between the roots o f the teeth'is a large m edullary space (Figs. 1, 3 and 5 ) . In the plane o f the upper one h a lf o f the roots o f the molars, this medullary space
roots come in direct contact with the buccal and lingual plates o f the alveolar process. The perforations in the lamina dura vary greatly in size and number as well
Fig. 2.— Higher magnification o f root-end region shown in Figure 1.
is spacious. O nly rarely are plates o f cancellous bone found bridging this space from buccal to lingual plate (Fig. 5 ). The lamina dura is truly a much perforated layer o f compact, laminated bone, with a narrow zone o f cancellous bone associated with it except where the
as in position. There is also a difference between the maxilla and mandible in this respect, there being a strong tendency fo r a greater number o f openings to be present on the interproximal surfaces o f the roots o f the maxilla, while, in the mandible, the greater number o f openings are toward the mandibular
Job-F ouser— Relationship o f the Teeth to the Mandibular Canal
canal. This fact appears to be deter mined by the source o f the largest blood supply. P R A C T I C A L C O N S ID E R A T IO N
The anatomic facts just pointed out have direct bearing on the treatment o f
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o f the alveolae o f the teeth to this layer o f bone, and the definite attachment o f the lamina dura to the floor o f the m axillary sinus. In abscesses, the cribri form nature o f the lamina dura and the floor o f the m axillary sinus becomes
Fig. 3.— F rontal section o f m axilla, showing slight tangential cut o f the first m olar and surrounding structures.
these tissues and on the pathologic manifestations that are frequently found in this area. In curettage o f this area, one should always remember the thinness o f the layer o f bone form ing the floor o f the m axillary sinus, the close proximity
important. The direct continuity o f the soft tissues lining the maxillary sinus with the peridental membrane and the large medullary spaces, which is a constant anatomic fact (Figs. 2 and 4 ) , permits easy metastasis.
1076
The Journal o f the American Dental Association
In interpreting radiograms, the ir regular character and cribriform nature o f the lamina dura should be consid ered. Not infrequently, enlarged open ings are found in the lamina dura so located as to give the impression in radiograms o f resorption areas, when,
maxilla. The compact bone, which comprises the buccal, labial and lingual plates, is thicker (Fig. 7 ) ; the haversian type o f bone predominates in the alveolar plates. Cancellous bone is o f the same general character as that found in the maxilla, although the smaller
Fig. 4.— Higher magnification o f root-end region o f m olar, showing rela tionship to the m axillary sinus and surrounding structures.
as a matter o f fact, they are normal structures (Figs. 2 and 5 ) . These facts hold true, though in a less intimate way, with those teeth not so closely related to the m axillary sinus (Fig. 6 ) . M A N D IB L E
The mandible presents a somewhat different structural picture, yet the histologic features o f the bone are o f a similar character to those found in the
medullary spaces appear to be more numerous. The w all o f the mandibular or in ferior dental canal is composed o f a thin layer o f compact, laminated bone that is extensively perforated, especially on the surface toward the apices o f the teeth. It is surrounded throughout its course by cancellous bone. The canal is closely associated with the lingual plate (Fig. 8)
Job-F ouser— Relationship o f the Teeth to the Mandibular Canal
and continues forw ard to the region o f the bicuspids, where it turns laterally to the mental foramen. This foramen terminates the canal proper, but the in cisive branches o f the inferior alveolar structures continue through the cancel-
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mandibular canal. The second and first molars are slightly more distant, as are the bicuspids. P R A C T I C A L C O N S ID E R A T IO N
The general character o f the bony structures is much the same as in the
Fig. 5.— Horizontal section o f the m axilla, showing character o f the bone near the root ends o f the m olar teeth and immediately below the floor o f the m axillary sinus.
lous portion o f the bone, between the bony plates, to be distributed to the cuspid and incisor teeth. The third molar, owing to its position at or near the angle o f the mandible, bears the closest relationship to the
maxilla, except that, in the mandible, we have the root ends o f the teeth closely related to the mandibular canal. In the surgical treatment o f chronic dento-alveolar abscess, frequently the operator injures the structures contained
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The Journal o f the American Dental Association
in the canal. T he character o f the bone and the close promixity o f the root ends to the canal make such injury possible (Fig. 8 ).
the pathologic changes that take place in these regions. In the correct interpretation o f pathologic changes, it is not only necessary to understand the tissue manifestations but it is also essential to know the normal anatomy and rela tionships o f the areas. It is o f the utmost importance that the
Fig. 7.-— Frontal section o f mandible in the region o f the mesial root o f the first molar.
Fig. 6.— Frontal section o f m axilla through the region o f the second bicuspid ( le ft) . C O N C L U S IO N
A thorough knowledge and proper consideration o f the anatomic structures o f the maxilla and mandible are o f basic importance. T he structures under con sideration bear a direct relationship to
operator have an accurate knowledge o f the normal as w ell as the pathologic anatomy o f these parts, as proper sur gical intervention, when necessary, is based upon the scientific knowledge o f the anatomic, physiologic and pathologic character o f the parts. W e hope that this contribution may help bring about a more accurate un derstanding o f these basic factors and a
Job-F ouser— Relationship of the Teeth to the Mandibular Canal
more accurate interpretation o f the pathologic changes occurring in these areas, and may result in more scientific surgical treatment.
1079
lamina dura has been considered as certain a barrier against the exit o f micro-organisms as that dense layer o f tissue between the dentin and the cementum. This research discloses that the lamina dura, instead o f being a bar-
Fig. 8.— Higher magnification o f root-end region shown in Figure 7. Note the lingual plate o f compact bone; the mandibular canal and contents, and the apical region. DISCU SSION
Alonzo No dine, London, England: This annihilates another o f those fallacies with which the dental profession is obsessed. The fact that the lamina dura is intact has been considered, fo r some time, as indisputable p ro o f that the tooth is not only free from infection but even safe and savable. The
rier, is a sieve. The numerous channels shown in the slides as extending through this structure are conclusive and convincing evi dence o f this fact. The infection within the tooth m ay be conveyed beyond the tooth into the circulation by means o f these channels and infect any tissue or organ fo r which they have an affinity.