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The tilted posterior tooth. Part I: Etiology, syndrome, and prevention
The tilted posterior tooth. Part I: Etiology, syndrome, and prevention Noah Stern, D. M. D., M. S. D.,* Abraham Revah, D. M. D.,* * and Adrian Becker, B. D. S., L. D. S., D. D.O. *** Hebrew University-Hadassah
Faculty of Dental Medicine, Jerusalem, Israel
1 he tilted posterior tooth represents a clinical problem which frequently confronts the dentist. The most common offender is the lower second molar. Although always mesially inclined, the degree of tilt is variable and often has a lingual component. However, this does not exclusively dictate either the severity of the problem nor its treatment.
ETIOLOGY The normal position of the teeth in the posterior segments of the dentition shows a slight mesial angulation in both the maxillae and in the mandible. It follows, therefore, that when the occlusal stroke imparts a vertical force along the long axes of the opposing teeth, a smaller mesial component is also present. This force is absorbed by the approximating teeth through the medium of the contact areas and is known as the anterior component of force. ’ The tilte4 molar results from loss of arch integrity at a site immediately mesial to it.’ Missing teeth. The loss of an interproximal contact, caused by the loss of a tooth, prevents the anterior component of force from functioning. The first mandibular molar is probably the most common tooth to be lost, thus rendering the second molar the most commonly tilted tooth (Fig. 1). Frequently, a similar tooth may be missing on the same side in both jaws, complicating the clinical picture (Fig. 2). Loss of tooth tissue. Loss of a normal contact area may be caused by proximal caries, a process which, if continued, will cause a considerable loss of calcified
dental tissue. Mesial movement of the posterior tooth into the carious cavity will occur as the unchecked response to the anterior component of force (Fig. 3). Ectopic eruption. Ectopic eruption of a second premolar is usually due to the early loss of its deciduous predecessor. When this occurs, the first permanent molar tilts mesially before the second premolar erupts into the arch. The premolar then has insufficient space in the arch and erupts ectopitally, usually on the lingual (Fig. 4). Occasionally, the second premolar erupts ectopitally while the deciduous second molar is retained beyond its normal time of exfoliation. ‘The extraction of the deciduous second molar leaves a space in the arch for which the first molar and the ectopically erupted second premoiar compete. The ectopicaiiy placed second premolar is distant from the arch and, although the tongue pressure tends to move this tooth toward the available space, the first molar will tilt mesially at a greater rate due to the unchecked anterior component of force and the eruptive force of the second molar. Thus the second premolar remains ectopically placed because of the mes.ial movement of the first molar and, in some cases, the distal movement of the first premolar. Intercuspation. The molar will not always tilt mesially following the loss of arch integ:rity mesial to it. Where there is adequate intercuspation, mesial movement will be minimal and may not occur at all. A naturally spaced dentition is unaffected by tooth loss, since this kind of dentition has stabilized itself without contact areas.
CLINICAL Supported in part by a grant from the joint Research Fund of the Hebrew University-Hadassah Faculty of Dental Medicine. *Associate Professor, Department of Oral Rehabilitation. **Lecturer, Department of Oral Rehabilitation. ***Clinical Senior Lecturer, Department of Orthodontics.
404
OCTOBER
1981
VOLUME
46
NUMBER
4
SYNDROME
Tilting of the molar. Mesial tilting of the second permanent molar is the most widely recognized sequel to loss of contact (Fig. 5). Should teeth which normally occlude with a tilted molar be missing,
0022-3913/81/100404
.t O4$OO.4O/OD 1981 The C. V. MoJby Co.
TILTED POSTERIOR
TOOTH
Fig. 1. Mesial and lingual migration molar after loss of first molar.
of lower second
Fig. 3. Proximal caries in molar has allowed tilting occur.
to
Fig. 2. First molars are missing in both jaws, and second molars are severely tilted mesially. Mandibular molar has elevated plane of occlusion and poor gingival tone. supraversion of the tilted tooth will also occur. Supraversion of the teeth is accompanied by growth of the alveolar process and, should it occur in the upper molar region, it usually incurs an extension of the maxillary sinus. Supraversion of teeth in the posterior region, together with the supporting bone, may present a clinical problem which persists after extraction. It may require surgical reshaping of the residual ridge for successful complete or removable partial dentures.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
Fig. 4. Early extraction of deciduous tooth led to tilting of adjacent teeth and lingual ectopic eruption of premolar. Tilting of the premolar. The premolar usually tilts distally, which has been explained in several ways. While contraction of scar tissue in the extraction wound may bring about distal movement,” evidence has been produced more recently that shows the strong influence of transseptal fibers of the periodontal ligament in moving teeth both mesially and
405
STERN, REVAH, AND BECKER
Fig. 5. Bite-wing radiograph shows loss of first mandibular molar and complete clinical syndrome of tilted second molar, with supraversion of upper molar. distally.’ It is quite feasible to propose that the transseptal fibers that become reestablished across an extraction wound contract as they mature into fully developed, coiled fibers. In this way, they produce a distal tilt of the premolar which is limited by the opposing transseptal fibers on the mesial aspect of that tooth.” The distal inclined plane of the maxillary canine occludes with the mesial inclined plane of the mandibular first premolar, exerting a distal force on the lower tooth.’ Distal tilting does not seem to occur in the following circumstances: (1) in a Class II malocclusion where the contact exists between upper and lower canines and (2) when the tongue may be inserted into an extraction space, particularly where more than one tooth has been removed. This has the effect of limiting the distal movement (Fig. 6). Space loss. Tilting of a molar and premolar toward each other gradually reduces the space previously occupied by the extracted tooth. Consequently, it is impossible to restore the space with a pontic of normal size. Furthermore, since the teeth tilt toward each other, the loss of parallelism is rapid and extreme (equivalent to the sum of the angles of tilt of the two teeth), increasing the practical difficulties in making a prosthesis. Transfer of forces. Two thirds of the fibers of the periodontal ligament are oblique.’ This facilitates the absorption of vertical occlusal forces. A tilted tooth cannot withstand these pressures in an equally efficient way, since occlusal forces are not transferred through the vertical axis of the tooth. Changes in occlusal plane. A tilted molar alters the plane of occlusion. The angle of the occlusal surface of the tooth relative to the condylar guidance will cause cuspal interference. If the lower molar is
406
Fig. 6. Tongue habitually fills extraction space, limiting distal movement of premolar. Note indentations of teeth on lateral surface of tongue. tilted, the angulation of the occlusal surface acts in the same way as a plane of occlusion which has been elevated, even though its occlusal level may not have been altered (Fig. 2). In other words, an elevated plane of occlusion makes the angulation of the occlusal surface more parallel to the direction of the condylar guidance. If the condylar guidance angle and the inclination of the occlusal surface of the tooth are exactly parallel, even a cuspless tooth will cause interference. Lingual tilting of the molar, which often occurs concomitantly wjth the mesial tilting, may also cause increased cuspal effectiveness and a potential for nonworking interference.” Infrabony pocket. A change occurs in the imaginary horizontal line which connects the cementoenamel junction of a tilted molar with that of the adjacent teeth. The level of bone in that region will alter accordingly to produce an angular crest.” As a result of the tilt, it becomes likely that an infrabony pocket will develop. Alveolar crest height. Mesial tilting reduces the distance between the alveolar crest and the cementoenamel junction mesially. The conservation of the normal width of this distance, called the biologic width, is necessary for the maintenance of gingival health.‘O, I1 The connective tissue attachment in this area serves to maintain the functional integrity of the underlying structures by its resistance to mechanical stresses. Reduction of the distance between the alveolar crest and the cementoenamel junction results in compression of the gingival fiber a#paratus. This usually results in lack of gingival tonus and a pseudopocket, which is susceptible to periodontal disease (Fig. 2).”
OCTOBER
1981
VOLUME
46
NUMBER
4
TILTED POSTERIOR
TOOTH
Supraversion of the opposing tooth. The upper first molar may erupt into the space of the extracted lower tooth. This results in loss of proximal contacts which may be reestablished more apically on an upper first molar in supraversion by mesial movement of the second molar or by mesial movement and tilting of both the first and second molars. This leads to further changes in the occlusal plane and in interarch relations, including the possibility of premature occlusal contacts. Should the interproximal contacts not reestablish, the spaces will increase with more supraversion, leading to food impaction and periodontal disease. In addition, in the event of poor gingival health adjacent to the extruded teeth, loss of the buccal bony plate may occur.
PREVENTION
REFERENCES 1.
2. 3. 4. 5.
6.
7. 8.
In general, repair of the alveolus and gingiva after extraction occurs in 6 to 8 weeks. The missing tooth should be replaced as soon as possible by a fixed or removable partial denture. If a permanent replacement cannot be made upon repair of the socket, a space maintainer should be placed until such time as the permanent restoration can be made. This temporary restoration may take many forms. A modified form of an A splint is one popular choice.‘” However, orthodontic bands indirectly adapted on a plaster cast and incorporating soldered elements to maintain the space, are an excellent alternative. The acid-etch technique may also be used to attach an acrylic resin pontic or the clinical crown of the originally extracted tooth to the adjacent teeth.‘“. I5 This technique has been successfully used in situations that require a temporary solution for 1 or 2 years, particularly in the anterior region.‘” The function of the space maintainer or prosthesis is not only to prevent tilting and space reduction but also to prevent supraversion of the opposing teeth. Therefore, any device must correctly conform with the occlusal scheme.
SUMMARY
9. 10.
11.
12.
13. 14.
15.
16.
Yalisove, I., and Deitz, J. B.: Telescopic Prosthesis Therapy, ed 1. Philadelphia, 1977, George F. Stric:kly Co., pp 104107. Amsterdam, M.: Periodontal prosthesis-Twenty-five years in retrospect. Alpha Omegan, Dec. 1974, p 13. Begg, P. R.: Begg Orthodontic Theory and Technique. Philadelphia 1965, W. B. Saunders Co., p 60. Moss, J. P., and Picton, D. C. A.: The migration of teeth in adult monkeys. Tram Eur Orthod Sot 48:443, 1972. Murphy, W. H.: Oxytetracycline microfluorescent comparison of orthodontic retraction into recent healed extraction sites. Am J Orthod 58:215, 1970. Amsterdam, M.: Lecture notes on “Form and function of the masticatory system” to graduate students in periodontics and periodontal prosthesis. University of Pennsylvania, School of Dental Medicine, 197611977. Goldman, H. M., and Cohen, D. W.: Periodontal Therapy, ed 5. St. Louis, 1973, The C. V. Mosby Co., p 40. Abrams, L.: Lecture notes on “Occlusal adjustment of the natural dentition by selective grinding” to the graduate students in periodontics and periodontal prosthesis. University of Pennsylvania, School of Dental Medicine, 1976/ 1977. Ritchey, B., and Orban, B.: The crest of the interdental alveolar septa. J Periodont 24:75, 1953. Ingber, S. J., Rose, L. F., and Coslet, J G.: The biologic width-A concept in periodontics and restorative dentistry. Alpha Omegan 10:62, 1977. Stern, N., and Becker, A.: Forced eruption-Biological and clinical considerations. In press, J Or;11 Rehabil 7:395, 1980. Coslet, J. G., Vanarsdall, R., and Weisgold, A.: Diagnosis and classification of delayed passive eruption of the dentogingival junction in the adult. Alpha Omegan I&24, 1977. Goldman, H. M., and Cohen, D. W.: Periodontal Therapy, ed 5. St. Louis, 1973, The C. V. Mosby (Co., pp 533-536. Kohavi, D., Stern, N., and Grajower, R.: A temporary space maintainer using acrylic resin teeth and a composite resin. J PROSTHET DENT 37:522, 1977. Becker, A., Stern, N., and Seizer, Z. Utilization of a dilacerated incisal tooth as its own space maintainer. J Dent 4:263, 1976. Revah, A., Rehany, A., Zalkind, M., and Stern, N.: A two-year clinical study of the durability of acrylic resin pontics attached to natural teeth using the acid-etched technique. Unpublished data.
Reprint requeststo: DR. NOAH STERN HEBREW UNIVERSITY-HADASSAH FACWLTY OF DENTAL MEDICINE P.O. Box 1172
The extraction of a tooth may have far-reaching ramifications on adjacent teeth, opposing teeth, occlusal scheme, and the periodontium. The best treatment is prevention.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
407
Faculty of Dental Medicine, Jerusalem, Israel
1 he tilted posterior tooth represents a clinical problem which frequently confronts the dentist. The most common offender is the lower second molar. Although always mesially inclined, the degree of tilt is variable and often has a lingual component. However, this does not exclusively dictate either the severity of the problem nor its treatment.
ETIOLOGY The normal position of the teeth in the posterior segments of the dentition shows a slight mesial angulation in both the maxillae and in the mandible. It follows, therefore, that when the occlusal stroke imparts a vertical force along the long axes of the opposing teeth, a smaller mesial component is also present. This force is absorbed by the approximating teeth through the medium of the contact areas and is known as the anterior component of force. ’ The tilte4 molar results from loss of arch integrity at a site immediately mesial to it.’ Missing teeth. The loss of an interproximal contact, caused by the loss of a tooth, prevents the anterior component of force from functioning. The first mandibular molar is probably the most common tooth to be lost, thus rendering the second molar the most commonly tilted tooth (Fig. 1). Frequently, a similar tooth may be missing on the same side in both jaws, complicating the clinical picture (Fig. 2). Loss of tooth tissue. Loss of a normal contact area may be caused by proximal caries, a process which, if continued, will cause a considerable loss of calcified
dental tissue. Mesial movement of the posterior tooth into the carious cavity will occur as the unchecked response to the anterior component of force (Fig. 3). Ectopic eruption. Ectopic eruption of a second premolar is usually due to the early loss of its deciduous predecessor. When this occurs, the first permanent molar tilts mesially before the second premolar erupts into the arch. The premolar then has insufficient space in the arch and erupts ectopitally, usually on the lingual (Fig. 4). Occasionally, the second premolar erupts ectopitally while the deciduous second molar is retained beyond its normal time of exfoliation. ‘The extraction of the deciduous second molar leaves a space in the arch for which the first molar and the ectopically erupted second premoiar compete. The ectopicaiiy placed second premolar is distant from the arch and, although the tongue pressure tends to move this tooth toward the available space, the first molar will tilt mesially at a greater rate due to the unchecked anterior component of force and the eruptive force of the second molar. Thus the second premolar remains ectopically placed because of the mes.ial movement of the first molar and, in some cases, the distal movement of the first premolar. Intercuspation. The molar will not always tilt mesially following the loss of arch integ:rity mesial to it. Where there is adequate intercuspation, mesial movement will be minimal and may not occur at all. A naturally spaced dentition is unaffected by tooth loss, since this kind of dentition has stabilized itself without contact areas.
CLINICAL Supported in part by a grant from the joint Research Fund of the Hebrew University-Hadassah Faculty of Dental Medicine. *Associate Professor, Department of Oral Rehabilitation. **Lecturer, Department of Oral Rehabilitation. ***Clinical Senior Lecturer, Department of Orthodontics.
404
OCTOBER
1981
VOLUME
46
NUMBER
4
SYNDROME
Tilting of the molar. Mesial tilting of the second permanent molar is the most widely recognized sequel to loss of contact (Fig. 5). Should teeth which normally occlude with a tilted molar be missing,
0022-3913/81/100404
.t O4$OO.4O/OD 1981 The C. V. MoJby Co.
TILTED POSTERIOR
TOOTH
Fig. 1. Mesial and lingual migration molar after loss of first molar.
of lower second
Fig. 3. Proximal caries in molar has allowed tilting occur.
to
Fig. 2. First molars are missing in both jaws, and second molars are severely tilted mesially. Mandibular molar has elevated plane of occlusion and poor gingival tone. supraversion of the tilted tooth will also occur. Supraversion of the teeth is accompanied by growth of the alveolar process and, should it occur in the upper molar region, it usually incurs an extension of the maxillary sinus. Supraversion of teeth in the posterior region, together with the supporting bone, may present a clinical problem which persists after extraction. It may require surgical reshaping of the residual ridge for successful complete or removable partial dentures.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
Fig. 4. Early extraction of deciduous tooth led to tilting of adjacent teeth and lingual ectopic eruption of premolar. Tilting of the premolar. The premolar usually tilts distally, which has been explained in several ways. While contraction of scar tissue in the extraction wound may bring about distal movement,” evidence has been produced more recently that shows the strong influence of transseptal fibers of the periodontal ligament in moving teeth both mesially and
405
STERN, REVAH, AND BECKER
Fig. 5. Bite-wing radiograph shows loss of first mandibular molar and complete clinical syndrome of tilted second molar, with supraversion of upper molar. distally.’ It is quite feasible to propose that the transseptal fibers that become reestablished across an extraction wound contract as they mature into fully developed, coiled fibers. In this way, they produce a distal tilt of the premolar which is limited by the opposing transseptal fibers on the mesial aspect of that tooth.” The distal inclined plane of the maxillary canine occludes with the mesial inclined plane of the mandibular first premolar, exerting a distal force on the lower tooth.’ Distal tilting does not seem to occur in the following circumstances: (1) in a Class II malocclusion where the contact exists between upper and lower canines and (2) when the tongue may be inserted into an extraction space, particularly where more than one tooth has been removed. This has the effect of limiting the distal movement (Fig. 6). Space loss. Tilting of a molar and premolar toward each other gradually reduces the space previously occupied by the extracted tooth. Consequently, it is impossible to restore the space with a pontic of normal size. Furthermore, since the teeth tilt toward each other, the loss of parallelism is rapid and extreme (equivalent to the sum of the angles of tilt of the two teeth), increasing the practical difficulties in making a prosthesis. Transfer of forces. Two thirds of the fibers of the periodontal ligament are oblique.’ This facilitates the absorption of vertical occlusal forces. A tilted tooth cannot withstand these pressures in an equally efficient way, since occlusal forces are not transferred through the vertical axis of the tooth. Changes in occlusal plane. A tilted molar alters the plane of occlusion. The angle of the occlusal surface of the tooth relative to the condylar guidance will cause cuspal interference. If the lower molar is
406
Fig. 6. Tongue habitually fills extraction space, limiting distal movement of premolar. Note indentations of teeth on lateral surface of tongue. tilted, the angulation of the occlusal surface acts in the same way as a plane of occlusion which has been elevated, even though its occlusal level may not have been altered (Fig. 2). In other words, an elevated plane of occlusion makes the angulation of the occlusal surface more parallel to the direction of the condylar guidance. If the condylar guidance angle and the inclination of the occlusal surface of the tooth are exactly parallel, even a cuspless tooth will cause interference. Lingual tilting of the molar, which often occurs concomitantly wjth the mesial tilting, may also cause increased cuspal effectiveness and a potential for nonworking interference.” Infrabony pocket. A change occurs in the imaginary horizontal line which connects the cementoenamel junction of a tilted molar with that of the adjacent teeth. The level of bone in that region will alter accordingly to produce an angular crest.” As a result of the tilt, it becomes likely that an infrabony pocket will develop. Alveolar crest height. Mesial tilting reduces the distance between the alveolar crest and the cementoenamel junction mesially. The conservation of the normal width of this distance, called the biologic width, is necessary for the maintenance of gingival health.‘O, I1 The connective tissue attachment in this area serves to maintain the functional integrity of the underlying structures by its resistance to mechanical stresses. Reduction of the distance between the alveolar crest and the cementoenamel junction results in compression of the gingival fiber a#paratus. This usually results in lack of gingival tonus and a pseudopocket, which is susceptible to periodontal disease (Fig. 2).”
OCTOBER
1981
VOLUME
46
NUMBER
4
TILTED POSTERIOR
TOOTH
Supraversion of the opposing tooth. The upper first molar may erupt into the space of the extracted lower tooth. This results in loss of proximal contacts which may be reestablished more apically on an upper first molar in supraversion by mesial movement of the second molar or by mesial movement and tilting of both the first and second molars. This leads to further changes in the occlusal plane and in interarch relations, including the possibility of premature occlusal contacts. Should the interproximal contacts not reestablish, the spaces will increase with more supraversion, leading to food impaction and periodontal disease. In addition, in the event of poor gingival health adjacent to the extruded teeth, loss of the buccal bony plate may occur.
PREVENTION
REFERENCES 1.
2. 3. 4. 5.
6.
7. 8.
In general, repair of the alveolus and gingiva after extraction occurs in 6 to 8 weeks. The missing tooth should be replaced as soon as possible by a fixed or removable partial denture. If a permanent replacement cannot be made upon repair of the socket, a space maintainer should be placed until such time as the permanent restoration can be made. This temporary restoration may take many forms. A modified form of an A splint is one popular choice.‘” However, orthodontic bands indirectly adapted on a plaster cast and incorporating soldered elements to maintain the space, are an excellent alternative. The acid-etch technique may also be used to attach an acrylic resin pontic or the clinical crown of the originally extracted tooth to the adjacent teeth.‘“. I5 This technique has been successfully used in situations that require a temporary solution for 1 or 2 years, particularly in the anterior region.‘” The function of the space maintainer or prosthesis is not only to prevent tilting and space reduction but also to prevent supraversion of the opposing teeth. Therefore, any device must correctly conform with the occlusal scheme.
SUMMARY
9. 10.
11.
12.
13. 14.
15.
16.
Yalisove, I., and Deitz, J. B.: Telescopic Prosthesis Therapy, ed 1. Philadelphia, 1977, George F. Stric:kly Co., pp 104107. Amsterdam, M.: Periodontal prosthesis-Twenty-five years in retrospect. Alpha Omegan, Dec. 1974, p 13. Begg, P. R.: Begg Orthodontic Theory and Technique. Philadelphia 1965, W. B. Saunders Co., p 60. Moss, J. P., and Picton, D. C. A.: The migration of teeth in adult monkeys. Tram Eur Orthod Sot 48:443, 1972. Murphy, W. H.: Oxytetracycline microfluorescent comparison of orthodontic retraction into recent healed extraction sites. Am J Orthod 58:215, 1970. Amsterdam, M.: Lecture notes on “Form and function of the masticatory system” to graduate students in periodontics and periodontal prosthesis. University of Pennsylvania, School of Dental Medicine, 197611977. Goldman, H. M., and Cohen, D. W.: Periodontal Therapy, ed 5. St. Louis, 1973, The C. V. Mosby Co., p 40. Abrams, L.: Lecture notes on “Occlusal adjustment of the natural dentition by selective grinding” to the graduate students in periodontics and periodontal prosthesis. University of Pennsylvania, School of Dental Medicine, 1976/ 1977. Ritchey, B., and Orban, B.: The crest of the interdental alveolar septa. J Periodont 24:75, 1953. Ingber, S. J., Rose, L. F., and Coslet, J G.: The biologic width-A concept in periodontics and restorative dentistry. Alpha Omegan 10:62, 1977. Stern, N., and Becker, A.: Forced eruption-Biological and clinical considerations. In press, J Or;11 Rehabil 7:395, 1980. Coslet, J. G., Vanarsdall, R., and Weisgold, A.: Diagnosis and classification of delayed passive eruption of the dentogingival junction in the adult. Alpha Omegan I&24, 1977. Goldman, H. M., and Cohen, D. W.: Periodontal Therapy, ed 5. St. Louis, 1973, The C. V. Mosby (Co., pp 533-536. Kohavi, D., Stern, N., and Grajower, R.: A temporary space maintainer using acrylic resin teeth and a composite resin. J PROSTHET DENT 37:522, 1977. Becker, A., Stern, N., and Seizer, Z. Utilization of a dilacerated incisal tooth as its own space maintainer. J Dent 4:263, 1976. Revah, A., Rehany, A., Zalkind, M., and Stern, N.: A two-year clinical study of the durability of acrylic resin pontics attached to natural teeth using the acid-etched technique. Unpublished data.
Reprint requeststo: DR. NOAH STERN HEBREW UNIVERSITY-HADASSAH FACWLTY OF DENTAL MEDICINE P.O. Box 1172
The extraction of a tooth may have far-reaching ramifications on adjacent teeth, opposing teeth, occlusal scheme, and the periodontium. The best treatment is prevention.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
407