A comparison of apical root resorption during orthodontic treatment in endodontically treated and vital teeth Steven W. Spurrier, DDS, MSD, Stanton H. Hall, DDS, MS, PhD,* Donald R. Joondeph, DDS, MS,** Peter A. Shapiro, DDS, MSD, and Richard A. Riedel, DDS, MSD*** Seattle, Wash.
The purpose of this study was to determine whether vital and endodontically treated incisors exhibit a similar severity of apical root resorption in response to orthodontic treatment. Forty-three patients who had one or more endodontically treated incisors before orthodontic treatment and who exhibited signs of apical root resorption after treatment were studied. In each patient the vital contralateral incisor served as a control. Vital incisors resorbed to a significantly greater degree than endodontically treated incisors (p -< 0.05). When patients were separated by gender, control teeth in males exhibited a statistically significant increase in resorption over control teeth in females. No significant differences were apparent between males and females when endodontically treated incisors were compared. (AM J ORTHOD DENTOFACORTHOP 1990;97:130-4.)
O n e of the most common complications associated with orthodontic treatment is the phenomenon known as apical root resorption. Numerous investigators have studied the relationship between apical root resorption and orthodontic movement in vital teeth. ,.29 Notwithstanding this concentrated effort, neither the cause nor the prognosis of apically resorbing teeth is fully understood. The general consensus is that apical root resorption of vital teeth occurs to some degree in nearly all orthodontic patients. There is inconclusive evidence regarding the frequency or extent of apical root resorption in endodontically treated teeth that are subject to orthodontic forces. Even though endodontically treated teeth respond to orthodontic forces in a manner similar to that of normal teeth, many orthodontists consider them to be more susceptible to apical root resorption. Wickwire et al. 3° reported that although endodontically treated teeth moved as readily as vital teeth, the endodontically treated teeth exhibited a greater frequency of root resorption than their vital controls. Conversely, other
From the School of Dentistry, University of Washington. This article is based on research submitted by the senior author in partial fulfillment of the requirements for the degree of Master of Science in Dentistry. This research was supported in part by the Orthodontic Memorial Fund. *Associate Professor, Department of Orthodontics. **Professor and Chairman, Department of Orthodontics. ***Professor Emeritus, Department of Orthodontics. 811110459
130
authors 3j'32 have reported no significant differences in the amount of root resorption. Although Mattison et al. 33 and Chivian 25 have proposed root canal therapy for the arrest of resorption occurring either internally or externally, neither of these studies looked specifically at the question of root resorption during orthodontic therapy. In view of the conflicting reports in the literature, the susceptibility of endodontically treated teeth to apical root resorption remains a controversial subject. The purpose of this study was to determine whether vital and endodontically treated incisors exhibit a similar severity of apical root resorption in response to orthodontic treatment.
MATERIALS AND METHODS Sample The subjects for this study were 43 patients (21 males and 22 females), who had one or more anterior teeth treated endodontically before orthodontic therapy. The sample was selected after a review of more than 12,000 patient records from five separate private orthodontic practices. The patients included in this study had completed multiband/bracket orthodontic therapy, with duration of active treatment exceeding 1 year. In order that a comparison of the amount and severity of root resorption could be made, each patient selected had some degree of resorption evident by the end of active treatment. All endodontic therapy had been com-
Voh,me97 Number 2
Apical resorption during treatment in endodontically treated and vital teeth
131
Fig. 1. Example of typical resorptive pattern.
pleted before band placement. The contralateral incisors had never had invasive pulp therapy, although the extent to which either tooth may have been traumatized was not known. Teeth with fractured or otherwise mutilated roots were not included in the study. In all cases radiographs were of good quality, showing the entire inciso-apical length of measured teeth with the apex clearly defined. Of the 43 patients selected, 72% (31) had Class II (22 Division 1, 9 Division 2) and 28% (12) had Class I occlusions.
Table I. Age of patients and duration of orthodontic treatment
Materials
to the nearest 1.0 mm (equivalent to 0.1 mm on the radiograph). Radiographs were standardized by measurement of the greatest distance from incisal edge to cementoenamel junction on each patient's pretreatment and posttreatment radiographs. These two values were compared in each patient. Differences were calculated as a foreshortening/elongation factor when incisoapical tooth length was measured. This method allowed for intrapatient standardization. Pretreatment and posttreatment orthodontic study casts were examined to ensure incisal integrity throughout the active treatment period. Patients with obvious incisal-edge changes were excluded from the study. Measurements were made of the greatest incisoapical dimension on each endodontically treated incisor and its contralateral control. Measurements were made and recorded from radiographs taken both before and after orthodontic treatment. From these values, tables
For each of the 43 patients, periapical radiographs of the endodontically treated and contralateral vital teeth, taken both before and after orthodontic treatment, were used (Fig. 1). The integrity of the incisal edges of the measured incisors was ensured by examination of pretreatment and posttreatment study casts. All measurements were made with the use of a Kodak slide projector and a transparent metric ruler. Methods
Radiographs were measured at a magnification of 10X as described by Kokich and Artun. 34 Radiographs were projected through a Kodak slide projector and adjusted to produce a magnification of 10X. This was accomplished by projection of an image of known dimension and adjustment of the projector until the proper magnification was achieved. A transparent metric ruler was used to measure the projected radiographic images
I Age Pretreatment Posttreatment Duration
Mean(yr-mo) 13-11 16-0 2-1
I
Range(yr-mo) 8-11 to 26-0 l 1-3 to 28-5 l-0 to 3-6
132 Spurrier et al.
Am. J. Orthod.Dentofac.Orthop. February1990
Table !1. Comparative results
Endo T~T2 vs Control T~T2* (mm) Endo T~T2 vs Control TtT2* (%) Endo TI to T2 (mm) Control T t to T2 (mm) Endo T~ to "1"2(%) Control T~ to Tz (%) Separated by gender Endo T~ to T: (nun) Control T~ to "1"2(mm) Endo T t to "1"2(%) Control T t to T2 (%)
Mean
SD
SE
-0.77 -2.74 1.28 2.05 5.14 7.88
! .75 6.31 1.09 1.49 3.88 5.71
0.27 0.96 0.17 0.23 0.59 0.87
0.006 0.007 0.003 0.0008 0.008 0.0009
S S S S S S
0.16 I. 13 0.43 4.08
0.54 0.72 1.29 2.85
0.11 0.16 0.26 0.64
0.624 0.011 0.720 0.017
NS St NS St
I
pvalue
I
Significance
Pretreatment-Tt. Posttreatment-T,. *Indicates greater change. iMales exhibited greater change.
were constructed for both millimetric amounts of resorption and percentage of root loss.
Analysis of data For all data collected, the mean value, standard deviation, and range were calculated. To determine statistical significance across time, the Student t test for paired data was used. Statistical significance was defined as p --< 0.05.
Error analysis Ten randomly selected patient radiographs were measured on three separate occasions at 1-week intervals to determine intrarater reliability. Variance from original measurements ranged from 0.00 mm to 0.35 mm. The mean error was 0.32 mm for the measurement of the endodontically treated teeth and 0.18 mm for the control measurement. RESULTS Age and treatment time
The mean pretreatment age for patients in this study was 13 years 11 months. The mean posttreatment age was 16 years 0 months. Average treatment time was 2 years I month (Table I).
Comparison of total sample The mean, standard deviation, and statistical significance of the total sample are listed in Table II. A statistically significant difference was observed in the millimetric apical resorption of the endodontically treated teeth as compared to the vital controls. A greater degree of root shortening occurred in the control teeth (mean difference, - 0 . 7 7 mm). Statistically significant
differences also were noted in the percentages of apical root resorption when endodontically treated teeth and vital controls were compared. The patients' control teeth again were found to exhibit the greatest mean amount of resorption (mean difference, 2.74%) (Table II). Twenty-nine (67%) of the forty-three patients exhibited greater resorption of their control teeth than their endodontically treated antimeres. In fourteen patients (33%) the endodontically treated teeth resorbed to a greater extent (Table III). Both the endodontically treated teeth and the vital control teeth showed statistically significant levels of apical root resorption. This was true for both millimetric and percentage changes. The actual amounts of resorption and the levels of significance did vary, however (Table II).
Comparison of sample by gender When the sample was subdivided by gender, no significant difference in the amount of resorption of the endodontically treated teeth was evident. Male patients exhibited a greater degree of change in the control teeth (p -< 0.02).
DISCUSSION This study found a statistically greater degree and frequency of mean apical root resorption in the vital control incisors when these teeth were compared with the contralateral endodontically treated incisors. This was true of both millimetric and percentage changes. Studies by Weiss 3z and Mattison 3~ reported no significant difference in the amount of root resorption between vital and nonvital teeth when both were subjected to
Volume97 Number2
Apical resorption during treatment in endodontically treated and vital teeth 133
T a b l e III. Millimeters o f root
I Patient
resorption
Endodontically treated
Control (vital) 0.3 3.3* 1.5' 0.0 0.4 6.2* 2.8* 0.9* 3.3* 2.4" 1.0 1.7" 5.1" 1.0 1.4 0.7* 1.4*
1
0.5*
2 3 4 5 6 7 8 9 I0 11 12 13 14 15 16 17
1.4 1.1 0.5* 0.7* 2.3 1.0 0.4 0.0 0.1 1.7" 0.4 0.8 1.9" 3.4* 0.6 0.4
18
1.5
2.7*
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
1.5* 0.2 0.5 0.3* 0.7 1.6 2.5* 3.6* 1.6 1.2 1.0 0.6 0.2 0.5 0.8 1.2 2.9* 2.0 0.1 1.4" 5.4* 1.2 2.8* 1.5 1.2
0.4 0.4* 2.5* 0.1 3.5* 2.2* 1.7 2.0 1.7" 1.8" 5.4* 4.2* 1.1" 1.8" 5.9* 3.0* 2.7 3.2* 0.3* 0.3 2.0 1.3" 2.2 2.1" 1.4*
*Indicates greatest change.
othodontic forces. However, Mattison's was an animal study carried out over a 4-month treatment period. This may have been too brief a time for significant differences to become apparent. W e i s s ' s sample consisted o f only eighteen patients who had completed orthodontic therapy. A sample o f this size is usually considered too small for statistical significance. Even though a statistically significant difference
was determined in the present study, it is the clinical significance that is the most critical. Root resorption is a clinical problem, and it is the clinical ramification o f this problem that is the most important to the everyday practice o f orthodontics. A mean difference o f 0.77 m m is virtually undetectable at the clinical level. Because o f this, a major finding of this study was the absence o f major differences between vital and endodontically treated incisors. With this knowledge, both vital and nonvital incisors can be treated with the same level o f confidence. However, in those patients who experience extreme levels of apical root resorption, the endodontically treated incisor Can be expected to maintain a greater degree of original root length. When separated by gender, control teeth exhibited a statistically significant difference. Male patients were found to have experienced the greatest mean amount o f resorption. Phillips 2~ found no difference in severity o f resorption between male and female patients. Newman, 2' however, found female patients to be more susceptible. It is o f interest that when endodontically treated incisors are compared, no statistical differences are apparent between male and female patients. The role of the dental pulp cannot be ignored when these results are considered. The results o f this study indicate that there is very little clinical difference in the amount or severity o f apical root resorption between vital and nonvital teeth. These findings in conjunction with earlier studies, suggest that endodontically treated incisors are of no greater liability to the orthodontist than are vital teeth. On a statistical level, however, endodontically treated incisors proved to be at decreased risk for apical root resorption. CONCLUSIONS 1. Endodontically treated incisors resorb with less frequency and severity than vital control teeth. 2. No significant difference in root resorption between male and female patients was detected in endodontically treated incisors. 3. Control teeth exhibited significantly more resorption in male patients than in female patents. 4. Even though statistical significance was noted, clinical differences are minimal when endodontically treated and vital incisors are compared. REFERENCES 1. Andreasen JO. Traumatic injuries of teeth. 2nd ed. Philadelphia: WB Saunders, 1981. 2. Bates S. Absorption. Br J Dent Sc L 1856;1:256. 3. Becks H. Root resorptions and their relation to pathologic bone formation. I,vr J ORTItOD1936;22:445-82.
"134
S p u r r i e r et al.
4. Becks H. Orthodontic prognosis. AM J ORTItOD 1939;25:61024. 5. Becks H, Cowden RC. Root resorptions and their relations to pathologic bone formation. Part II. AM J ORTIIOD 1942;28:51326. 6. Carpol H. A qualitative roentgenographic evaluation of root length in hypothyroid patients. AM J ORTHOD 1961;47:586-95. 7. Copeland S. Root resorption in maxillary central incisors following active orthodontic treatment. AM J ORTHOD DENTOFAC OR~tOP 1986;89:51-5. 8. DeShields RW. A study of root resorption in treated Class 1I Division I malocclusions. Angle Orthod 1969;39:231-45. 9. Frantz D. Apical root resorption in the anterior open-bite malocclusion [Masters Thesis]. Seattle, Washington: University of Washington, 1965. I0. Gerstein H. Techniques in clinical endodontics. Philadelphia: WB Saunders, 1983. 11. Goldson L, Malmgren O. Orthodontic treatment of traumatized teeth. In: Andreasen JO. Traumatic injuries of the teeth. 2nd ed. Philadelphia: WB Saunders, 1981. 12. Hemley S. The incidence of root resorption of vital permanent teeth. J Dent Res 1941;20:133-41. 13. Henry JL, Weinmann JP. The pattern of resorption and repair of human cementum. J Am Dent Assoc 1951;43:270-90. 14. Ketcham AH. A preliminary report of an investigation of apical resorption of permanent teeth, lrzr J ORTHOD 1927;13:97-127. 15. Ketcham AH. A progress report of an investigation of apical root resorption of vital permanent teeth. INT J ORTIIOD 1929; 15:310-28. 16. Kronfeld R. The resorption of the roots of deciduous teeth. Dent Cosmos 1932;74:103. 17. Malmgren O, Goldson L, Hill C, et al. Root resorption after orthodontic treatment of traumatized teeth. AM J ORTHOD 1982; 82:487-91. 18. MarshallJA. Deficient diets and experimental malocclusion considered from the clinical aspect. IrzPJ ORTItOD 1932;18:438-49. 19. Marshall JA. The classification, etiology, diagnosis, prognosis, and treatment of radicular resorption of teeth. Ircr J ORTHOD 1934;20:731-49. 20. Massler M, Malone AJ. Root resorption in human permanent teeth. AM J ORTtfOD 1954;40:619-33.
Am. J. Orthod. Dentofac. Orthop. February 1990
21. NewmanW. Possible etiologic factorsinextemalrootresorption. AM J ORTttOD 1975;67:522-39. 22. Oppenheim A. Biologic orthodontic therapy and reality. Angle Orthod 1936;6:153-83. 23. Oppenheim A. Human tissue response to orthodontic intervention of short and long duration. AM J ORTItOD 1942;2:263-301. 24. Ottolengui R. The physiologic and pathologic resorption of tooth roots. Dent Items Interest 1914;36:355. 25. Chivian M. In: Cohen S. Bums DC, eds. Pathways of the pulp. 4th ed. St. Louis: CV Mosby, 1987. 26. Phillips JR. Apical root resorption under orthodontic therapy. Angle Orthod 1955;25:1-12. 27. Remington D. Master thesis. Seattle, Washington: University of Washington, 1982. 28. Rudolph CE. A comparative study in root resorption in permanent teeth. J Am Dent Assoc 1936;23:822. 29. Rudolph CE. An evaluationofroot resorption during orthodontic treatment. J Dent Res 1940;19:367-71. 30. Wickwire NA, McNeil MH, Norton LA, Duell RC. The effects of tooth movement upon endodontically treated teeth. Angle Orthbd 1974;44:235-42. 31. Mattison GD. Orthodontic root resorption of vital and endodontically treated teeth. J Endod 1984;10:354-8. 32. Weiss SD. Root resorption during orthodontic treatment in endodontieally treated and vital teeth [Master's Thesis]. Memphis, Tennessee: University of Tennessee Department of Orthodontics, 1969. 33. Mattison GD, Gholston LR, Boyd P. Orthodontic external root resorption--endodontie considerations. J Endod 1983;9:253-6. 34. Kokich VG, Artun ]. Long-term effect of root proximity on periodontal health after orthodontic treatment. AM J ORTHOD D~q'rOFAC ORTHOP 1987;91:125-30. Reprint requests to:
Dr. Stanton H. Hall Department of Orthodontics-SM46 University of Washington School of DentistrySeattle, WA 98195
The purpose of this study was to determine whether vital and endodontically treated incisors exhibit a similar severity of apical root resorption in response to orthodontic treatment. Forty-three patients who had one or more endodontically treated incisors before orthodontic treatment and who exhibited signs of apical root resorption after treatment were studied. In each patient the vital contralateral incisor served as a control. Vital incisors resorbed to a significantly greater degree than endodontically treated incisors (p -< 0.05). When patients were separated by gender, control teeth in males exhibited a statistically significant increase in resorption over control teeth in females. No significant differences were apparent between males and females when endodontically treated incisors were compared. (AM J ORTHOD DENTOFACORTHOP 1990;97:130-4.)
O n e of the most common complications associated with orthodontic treatment is the phenomenon known as apical root resorption. Numerous investigators have studied the relationship between apical root resorption and orthodontic movement in vital teeth. ,.29 Notwithstanding this concentrated effort, neither the cause nor the prognosis of apically resorbing teeth is fully understood. The general consensus is that apical root resorption of vital teeth occurs to some degree in nearly all orthodontic patients. There is inconclusive evidence regarding the frequency or extent of apical root resorption in endodontically treated teeth that are subject to orthodontic forces. Even though endodontically treated teeth respond to orthodontic forces in a manner similar to that of normal teeth, many orthodontists consider them to be more susceptible to apical root resorption. Wickwire et al. 3° reported that although endodontically treated teeth moved as readily as vital teeth, the endodontically treated teeth exhibited a greater frequency of root resorption than their vital controls. Conversely, other
From the School of Dentistry, University of Washington. This article is based on research submitted by the senior author in partial fulfillment of the requirements for the degree of Master of Science in Dentistry. This research was supported in part by the Orthodontic Memorial Fund. *Associate Professor, Department of Orthodontics. **Professor and Chairman, Department of Orthodontics. ***Professor Emeritus, Department of Orthodontics. 811110459
130
authors 3j'32 have reported no significant differences in the amount of root resorption. Although Mattison et al. 33 and Chivian 25 have proposed root canal therapy for the arrest of resorption occurring either internally or externally, neither of these studies looked specifically at the question of root resorption during orthodontic therapy. In view of the conflicting reports in the literature, the susceptibility of endodontically treated teeth to apical root resorption remains a controversial subject. The purpose of this study was to determine whether vital and endodontically treated incisors exhibit a similar severity of apical root resorption in response to orthodontic treatment.
MATERIALS AND METHODS Sample The subjects for this study were 43 patients (21 males and 22 females), who had one or more anterior teeth treated endodontically before orthodontic therapy. The sample was selected after a review of more than 12,000 patient records from five separate private orthodontic practices. The patients included in this study had completed multiband/bracket orthodontic therapy, with duration of active treatment exceeding 1 year. In order that a comparison of the amount and severity of root resorption could be made, each patient selected had some degree of resorption evident by the end of active treatment. All endodontic therapy had been com-
Voh,me97 Number 2
Apical resorption during treatment in endodontically treated and vital teeth
131
Fig. 1. Example of typical resorptive pattern.
pleted before band placement. The contralateral incisors had never had invasive pulp therapy, although the extent to which either tooth may have been traumatized was not known. Teeth with fractured or otherwise mutilated roots were not included in the study. In all cases radiographs were of good quality, showing the entire inciso-apical length of measured teeth with the apex clearly defined. Of the 43 patients selected, 72% (31) had Class II (22 Division 1, 9 Division 2) and 28% (12) had Class I occlusions.
Table I. Age of patients and duration of orthodontic treatment
Materials
to the nearest 1.0 mm (equivalent to 0.1 mm on the radiograph). Radiographs were standardized by measurement of the greatest distance from incisal edge to cementoenamel junction on each patient's pretreatment and posttreatment radiographs. These two values were compared in each patient. Differences were calculated as a foreshortening/elongation factor when incisoapical tooth length was measured. This method allowed for intrapatient standardization. Pretreatment and posttreatment orthodontic study casts were examined to ensure incisal integrity throughout the active treatment period. Patients with obvious incisal-edge changes were excluded from the study. Measurements were made of the greatest incisoapical dimension on each endodontically treated incisor and its contralateral control. Measurements were made and recorded from radiographs taken both before and after orthodontic treatment. From these values, tables
For each of the 43 patients, periapical radiographs of the endodontically treated and contralateral vital teeth, taken both before and after orthodontic treatment, were used (Fig. 1). The integrity of the incisal edges of the measured incisors was ensured by examination of pretreatment and posttreatment study casts. All measurements were made with the use of a Kodak slide projector and a transparent metric ruler. Methods
Radiographs were measured at a magnification of 10X as described by Kokich and Artun. 34 Radiographs were projected through a Kodak slide projector and adjusted to produce a magnification of 10X. This was accomplished by projection of an image of known dimension and adjustment of the projector until the proper magnification was achieved. A transparent metric ruler was used to measure the projected radiographic images
I Age Pretreatment Posttreatment Duration
Mean(yr-mo) 13-11 16-0 2-1
I
Range(yr-mo) 8-11 to 26-0 l 1-3 to 28-5 l-0 to 3-6
132 Spurrier et al.
Am. J. Orthod.Dentofac.Orthop. February1990
Table !1. Comparative results
Endo T~T2 vs Control T~T2* (mm) Endo T~T2 vs Control TtT2* (%) Endo TI to T2 (mm) Control T t to T2 (mm) Endo T~ to "1"2(%) Control T~ to Tz (%) Separated by gender Endo T~ to T: (nun) Control T~ to "1"2(mm) Endo T t to "1"2(%) Control T t to T2 (%)
Mean
SD
SE
-0.77 -2.74 1.28 2.05 5.14 7.88
! .75 6.31 1.09 1.49 3.88 5.71
0.27 0.96 0.17 0.23 0.59 0.87
0.006 0.007 0.003 0.0008 0.008 0.0009
S S S S S S
0.16 I. 13 0.43 4.08
0.54 0.72 1.29 2.85
0.11 0.16 0.26 0.64
0.624 0.011 0.720 0.017
NS St NS St
I
pvalue
I
Significance
Pretreatment-Tt. Posttreatment-T,. *Indicates greater change. iMales exhibited greater change.
were constructed for both millimetric amounts of resorption and percentage of root loss.
Analysis of data For all data collected, the mean value, standard deviation, and range were calculated. To determine statistical significance across time, the Student t test for paired data was used. Statistical significance was defined as p --< 0.05.
Error analysis Ten randomly selected patient radiographs were measured on three separate occasions at 1-week intervals to determine intrarater reliability. Variance from original measurements ranged from 0.00 mm to 0.35 mm. The mean error was 0.32 mm for the measurement of the endodontically treated teeth and 0.18 mm for the control measurement. RESULTS Age and treatment time
The mean pretreatment age for patients in this study was 13 years 11 months. The mean posttreatment age was 16 years 0 months. Average treatment time was 2 years I month (Table I).
Comparison of total sample The mean, standard deviation, and statistical significance of the total sample are listed in Table II. A statistically significant difference was observed in the millimetric apical resorption of the endodontically treated teeth as compared to the vital controls. A greater degree of root shortening occurred in the control teeth (mean difference, - 0 . 7 7 mm). Statistically significant
differences also were noted in the percentages of apical root resorption when endodontically treated teeth and vital controls were compared. The patients' control teeth again were found to exhibit the greatest mean amount of resorption (mean difference, 2.74%) (Table II). Twenty-nine (67%) of the forty-three patients exhibited greater resorption of their control teeth than their endodontically treated antimeres. In fourteen patients (33%) the endodontically treated teeth resorbed to a greater extent (Table III). Both the endodontically treated teeth and the vital control teeth showed statistically significant levels of apical root resorption. This was true for both millimetric and percentage changes. The actual amounts of resorption and the levels of significance did vary, however (Table II).
Comparison of sample by gender When the sample was subdivided by gender, no significant difference in the amount of resorption of the endodontically treated teeth was evident. Male patients exhibited a greater degree of change in the control teeth (p -< 0.02).
DISCUSSION This study found a statistically greater degree and frequency of mean apical root resorption in the vital control incisors when these teeth were compared with the contralateral endodontically treated incisors. This was true of both millimetric and percentage changes. Studies by Weiss 3z and Mattison 3~ reported no significant difference in the amount of root resorption between vital and nonvital teeth when both were subjected to
Volume97 Number2
Apical resorption during treatment in endodontically treated and vital teeth 133
T a b l e III. Millimeters o f root
I Patient
resorption
Endodontically treated
Control (vital) 0.3 3.3* 1.5' 0.0 0.4 6.2* 2.8* 0.9* 3.3* 2.4" 1.0 1.7" 5.1" 1.0 1.4 0.7* 1.4*
1
0.5*
2 3 4 5 6 7 8 9 I0 11 12 13 14 15 16 17
1.4 1.1 0.5* 0.7* 2.3 1.0 0.4 0.0 0.1 1.7" 0.4 0.8 1.9" 3.4* 0.6 0.4
18
1.5
2.7*
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
1.5* 0.2 0.5 0.3* 0.7 1.6 2.5* 3.6* 1.6 1.2 1.0 0.6 0.2 0.5 0.8 1.2 2.9* 2.0 0.1 1.4" 5.4* 1.2 2.8* 1.5 1.2
0.4 0.4* 2.5* 0.1 3.5* 2.2* 1.7 2.0 1.7" 1.8" 5.4* 4.2* 1.1" 1.8" 5.9* 3.0* 2.7 3.2* 0.3* 0.3 2.0 1.3" 2.2 2.1" 1.4*
*Indicates greatest change.
othodontic forces. However, Mattison's was an animal study carried out over a 4-month treatment period. This may have been too brief a time for significant differences to become apparent. W e i s s ' s sample consisted o f only eighteen patients who had completed orthodontic therapy. A sample o f this size is usually considered too small for statistical significance. Even though a statistically significant difference
was determined in the present study, it is the clinical significance that is the most critical. Root resorption is a clinical problem, and it is the clinical ramification o f this problem that is the most important to the everyday practice o f orthodontics. A mean difference o f 0.77 m m is virtually undetectable at the clinical level. Because o f this, a major finding of this study was the absence o f major differences between vital and endodontically treated incisors. With this knowledge, both vital and nonvital incisors can be treated with the same level o f confidence. However, in those patients who experience extreme levels of apical root resorption, the endodontically treated incisor Can be expected to maintain a greater degree of original root length. When separated by gender, control teeth exhibited a statistically significant difference. Male patients were found to have experienced the greatest mean amount o f resorption. Phillips 2~ found no difference in severity o f resorption between male and female patients. Newman, 2' however, found female patients to be more susceptible. It is o f interest that when endodontically treated incisors are compared, no statistical differences are apparent between male and female patients. The role of the dental pulp cannot be ignored when these results are considered. The results o f this study indicate that there is very little clinical difference in the amount or severity o f apical root resorption between vital and nonvital teeth. These findings in conjunction with earlier studies, suggest that endodontically treated incisors are of no greater liability to the orthodontist than are vital teeth. On a statistical level, however, endodontically treated incisors proved to be at decreased risk for apical root resorption. CONCLUSIONS 1. Endodontically treated incisors resorb with less frequency and severity than vital control teeth. 2. No significant difference in root resorption between male and female patients was detected in endodontically treated incisors. 3. Control teeth exhibited significantly more resorption in male patients than in female patents. 4. Even though statistical significance was noted, clinical differences are minimal when endodontically treated and vital incisors are compared. REFERENCES 1. Andreasen JO. Traumatic injuries of teeth. 2nd ed. Philadelphia: WB Saunders, 1981. 2. Bates S. Absorption. Br J Dent Sc L 1856;1:256. 3. Becks H. Root resorptions and their relation to pathologic bone formation. I,vr J ORTItOD1936;22:445-82.
"134
S p u r r i e r et al.
4. Becks H. Orthodontic prognosis. AM J ORTItOD 1939;25:61024. 5. Becks H, Cowden RC. Root resorptions and their relations to pathologic bone formation. Part II. AM J ORTIIOD 1942;28:51326. 6. Carpol H. A qualitative roentgenographic evaluation of root length in hypothyroid patients. AM J ORTHOD 1961;47:586-95. 7. Copeland S. Root resorption in maxillary central incisors following active orthodontic treatment. AM J ORTHOD DENTOFAC OR~tOP 1986;89:51-5. 8. DeShields RW. A study of root resorption in treated Class 1I Division I malocclusions. Angle Orthod 1969;39:231-45. 9. Frantz D. Apical root resorption in the anterior open-bite malocclusion [Masters Thesis]. Seattle, Washington: University of Washington, 1965. I0. Gerstein H. Techniques in clinical endodontics. Philadelphia: WB Saunders, 1983. 11. Goldson L, Malmgren O. Orthodontic treatment of traumatized teeth. In: Andreasen JO. Traumatic injuries of the teeth. 2nd ed. Philadelphia: WB Saunders, 1981. 12. Hemley S. The incidence of root resorption of vital permanent teeth. J Dent Res 1941;20:133-41. 13. Henry JL, Weinmann JP. The pattern of resorption and repair of human cementum. J Am Dent Assoc 1951;43:270-90. 14. Ketcham AH. A preliminary report of an investigation of apical resorption of permanent teeth, lrzr J ORTHOD 1927;13:97-127. 15. Ketcham AH. A progress report of an investigation of apical root resorption of vital permanent teeth. INT J ORTIIOD 1929; 15:310-28. 16. Kronfeld R. The resorption of the roots of deciduous teeth. Dent Cosmos 1932;74:103. 17. Malmgren O, Goldson L, Hill C, et al. Root resorption after orthodontic treatment of traumatized teeth. AM J ORTHOD 1982; 82:487-91. 18. MarshallJA. Deficient diets and experimental malocclusion considered from the clinical aspect. IrzPJ ORTItOD 1932;18:438-49. 19. Marshall JA. The classification, etiology, diagnosis, prognosis, and treatment of radicular resorption of teeth. Ircr J ORTHOD 1934;20:731-49. 20. Massler M, Malone AJ. Root resorption in human permanent teeth. AM J ORTtfOD 1954;40:619-33.
Am. J. Orthod. Dentofac. Orthop. February 1990
21. NewmanW. Possible etiologic factorsinextemalrootresorption. AM J ORTttOD 1975;67:522-39. 22. Oppenheim A. Biologic orthodontic therapy and reality. Angle Orthod 1936;6:153-83. 23. Oppenheim A. Human tissue response to orthodontic intervention of short and long duration. AM J ORTItOD 1942;2:263-301. 24. Ottolengui R. The physiologic and pathologic resorption of tooth roots. Dent Items Interest 1914;36:355. 25. Chivian M. In: Cohen S. Bums DC, eds. Pathways of the pulp. 4th ed. St. Louis: CV Mosby, 1987. 26. Phillips JR. Apical root resorption under orthodontic therapy. Angle Orthod 1955;25:1-12. 27. Remington D. Master thesis. Seattle, Washington: University of Washington, 1982. 28. Rudolph CE. A comparative study in root resorption in permanent teeth. J Am Dent Assoc 1936;23:822. 29. Rudolph CE. An evaluationofroot resorption during orthodontic treatment. J Dent Res 1940;19:367-71. 30. Wickwire NA, McNeil MH, Norton LA, Duell RC. The effects of tooth movement upon endodontically treated teeth. Angle Orthbd 1974;44:235-42. 31. Mattison GD. Orthodontic root resorption of vital and endodontically treated teeth. J Endod 1984;10:354-8. 32. Weiss SD. Root resorption during orthodontic treatment in endodontieally treated and vital teeth [Master's Thesis]. Memphis, Tennessee: University of Tennessee Department of Orthodontics, 1969. 33. Mattison GD, Gholston LR, Boyd P. Orthodontic external root resorption--endodontie considerations. J Endod 1983;9:253-6. 34. Kokich VG, Artun ]. Long-term effect of root proximity on periodontal health after orthodontic treatment. AM J ORTHOD D~q'rOFAC ORTHOP 1987;91:125-30. Reprint requests to:
Dr. Stanton H. Hall Department of Orthodontics-SM46 University of Washington School of DentistrySeattle, WA 98195
