Effect of stannous fluoride and tetracycline on periodontal repair after delayed tooth replantation in dogs
Knut A. Selvig\ Kjell Bjorvatn\ Gary C. Bogle^ and Ulf M. E. Wikesjo' 'School of Dentistry, University of Bergen, Bergen, Norway and ^School of Dentistry, Loma Linda University, Loma Linda, California, USA
Selvig KA, Bjorvatn K, Bogle GC, Wikesjo UME: Effect of stannous fluoride and tetracycline on periodontal repair after delayed tooth replantation in dogs. Scand f Dent Res 1992; 100: 200-3. Previous studies have indicated that inflammatory resorption and ankylosis, which are frequent sequela after delayed tooth replantation, can be greatly reduced by treating the root surface with 1% solutions of stannous fluoride and tetracycline. However, the SnF, conditioning leaves a long-standing inflammatory reaction in the periodontal ligament. To examine whether a more dilute SnF2 solution would reduce postoperative inflammation without jeopardizing any beneficial effects, anterior teeth in three young adult beagles were extracted and allowed to air-dry for 45 min. They were then immersed in 0.1% SnFj for 5 min, rinsed in saline, immersed in 1% doxycycline HCl for 5 min, rinsed, and replanted. Control teeth were air-dried and replanted without further treatment. Block biopsies were harvested after 4 wk of healing and processed for histometric analysis. In experimental teeth, 85% of the root surface area showed normal healing, compared to 33% in control teeth. Conversely, resorption and ankylosis were more frequent in controls than in experimental teeth. A persisting inflammatory reaction either adjacent to or at a distance from the root surface was seen in limited areas in both experimental and control teeth. Compared to preceding studies, the fmdings indicate that reducing the strength of the SnFj solution from 1% to 0.1% may result in less persistent inflammation, at the cost, however, of less complete prevention of inflammatory resorption and ankylosis.
Clinical observations and experimental studies in dogs and primates have indicated that teeth replanted shortly after traumatic or experimental avulsion may heal with complete restoration of the periodontal structures (1, 2). On the other hand, teeth that have been exarticulated over a longer period of time show an increased tendency toward ankylosis and resorption (3-7). Soaking bench-dried teeth in a solution of either sodium fluoride or stannous fluoride prior to replantation has been shown to reduce the frequency of ankylosis and resorption (8, 9). These findings, however, are not unequivocal. Other studies have reported that pretreatment of roots with either neutral or acidulated sodium fluoride does not reduce root resorption and ankylosis (10, 11). The lack of agreement in these early studies may indicate that not only the fluoride ion, but also the cation in-
Key vi/ords: fluorides; tetracyciine; tooth reimplantation; traumatology, dental Knut A. Seivig, Department of Dental Research, University of Bergen Schooi of Dentistry, Arstadveien 17, N-5009 Bergen, Norvi^ay Accepted for publication 23 August 1991
volved and the pH ofthe solution, should be taken into consideration. While treatment with stannous fluoride may prevent root resorption in a short-term experiment, it also seems to delay resolution of the inflammatory phase of healing in the gingiva and periodontal ligament (12). If the stannous fluoride treatment is followed by immersion of the root in doxycycline, however, this adverse reaction is greatly diminished (12, 13). In a previous study of healing following delayed replantation, root surfaces were treated with 1% stannous fluoride followed by 1% doxycychne hydrochloride (12). This resulted in a dramatic reduction in the amount of root resorption compared to no treatment or doxycycline alone. Significantly, ankylosis did not occur. However, the specimens showed a high frequency of inflammatory reaction
2 and tetracyeline in tooth replantation in the periodontal ligament in the absence of resorption. The long-standing inflammatory reaction is presumably an effect of the stannous fluoride rather than of the tetracyeline treatment. In the present study, therefore, the concentration of the stannous fluoride solution was reduced from 1.0% to 0.1% in an attempt to reduce the inflammatory reaction. Material and methods Animals - The maxillary first and second incisors (II and 12) and mandibular first, second, and third incisors (II, 12, and 13) in three young adult beagle dogs were available for experimentation. In one of the dogs, three teeth fractured during extraction and were excluded from the study. The roots of these teeth, as well as the unoperated maxillary third incisors, remained in the jaws and were present in the histologic sections. Since previous studies (8, 9, 12) have shown a consistent healing result following delayed tooth replantation and, thus, may be regarded as the basis for this experimental study, only one quadrant in each animal was designated as a control, while three quadrants were used for the experimental procedure. The distribution of the experimental and control teeth is shown in Table 1. Experimental procedures ~ General anesthesia was accomplished by intravenous administration of pentobarbital sodium. The designated teeth were carefully extracted with forceps or elevators. The teeth were rinsed in saline, wiped dry, placed on filter paper, and left to dry on the bench for 45 min. The experimental teeth were then immersed in a 0.1% aqueous solution of SnF, for 5 min, rinsed briefly in sterile saline, immersed in 1% doxycycline HCI for 5 min, rinsed in saline, and replanted. Root surface instrumentation was not carried out. Control teeth were bench-dried for 45 min and then replanted without any root surface conditioning. The teeth were reseated in the alveolus, using gentle finger pressure. No fixation was used. Each animal received a single dose of penicillin + dihydrostreptomycin (Combiotic, Pfizer, Inc., NY) intramuscularly immediately after surgery. The dogs were fed a standard laboratory diet of soft consistency for 4 wk and were then sacrificed by intrave-
Table 1
'
Distribution of experimental teeth by animal and treatment procedure D 1 D2 D 3 12*11* 11 12 12 11 11 12 12 11 P 13 12 11 11 12 13 13*I2*I1* 11 12 13 13*12* 12 13 * Controls.
201
nous administration of sodium pentobarbital. A healing period of 4 wk was chosen to coincide with that of the preceding study (12). Previous experience with this model has indicated that, within this time period, pulpal necrosis, if occurring, will not have affected the healing response in the periapical region. The experimental protocol was approved by the institutional committee for animal experimentation. Specimen preparation - Anterior portions of the maxilla and mandible were removed, divided into right and left halves, fixed in 10% buffered formalin, demineralized in 5% formic acid, and embedded in paraffin wax. Horizontal sections were made at 7 iim through the incisor roots. Owing to the nonparallelism of the long axes of the iticisors, the resulting sections did not strictly represent transverse sections of all teeth in each block. The difference in angulation of the sections, however, was not considered to influence significantly the evaluation of the experimental results. Sections were stained with hematoxylin-eosin. Histometric analysis - Histologic evaluation of healing was carried out for each tooth separately. One section per 0.5 mm of root length was selected for histometric analysis. In each section, healing was examined at 12 points along the root surface, separated by an angle of 30° through the center of the tooth (14-16). At each measuring point, the presence of surface resorption, infiammatory resorption, ankylosis (replacement resorption), and inflammatory reaction without resorption was recorded. Each healing result was further categorized as active, arrested, or repaired, as appropriate (17). The absence of such sequela was recorded as uncomplicated healing. Eor each tooth, the proportion of the root surface showing the different healing results was calculated and expressed as a percentage. Statistical analysis included calculation of the means and standard deviations for experimental and control teeth. Whenever appropriate, the significance level of observed differences was evaluated by the Wilcoxon two-sample rank-sum test. Results
•
Clinically, all teeth healed uneventfully. No teeth were lost in the postoperative period. The histologic and histometric evaluation in experimental and control teeth is shown in Table 2. Downgrowth of junctional epithelium along the root surface was negligible. Uncomplicated healing predominated in the experimental teeth while the control teeth showed significantly more surface resorption and ankylosis. Generally, all teeth in each group showed a consistent healing pattern itidependent of tooth posi-
202
Selvig et al.
Table 2 Histometric results. Tissue reaction bv treatment group in percent of available surface area (mean + SD) No. of Normal Inflammation Surface Inflammatory teeth Group healitig resorption without resorptioti resorption Ankylosis Control 7 32.6 + 3.8 29.2 + 20.5 0.5+1.4 37.2 + 21.4 0.5±0.6 Experimental 20 85.0 + 7.2 10.6±7.9 0.7+1.4 0.2 + 0.5 4.1+6.3 a* 0.001 0.05 n.s. n.s. 0.001 Wilcoxon two-sample rank-sum test.
tion or dog, as indicated by the relatively small standard deviations. An exception was the variable amount of surface resorption and ankylosis seen in the control teeth. This result was due to a high frequency of ankylosis (range 58-69% of the root surf'ace) and a limited amount of surface resorption (5-8%) in the control teeth in Dogs 1 and 2, while in Dog 3, the control teeth showed less ankylosis (15-23%) and more surface resorption (38-50%). At sites adjacent to overt ankylosis, it was sometimes difficult to differentiate between root surface
facing periodontal ligament and root surface facing a bone marrow space. This was probably the greatest single source of analytic error and may have resulted in some sites in ankylosis-affected teeth being recorded as showing uncomplicated healing or surface resorption which, in fact, were part of an ankylotic process. Further analysis showed that surface resorption defects, in the experimental as well as the control teeth, were mostly arrested or showed a variable amount of repair. Superficial resorption defects which appeared active were seen in 8 of 20 experimental teeth and in 4 of 7 control teeth and accounted for 0.5-2.8% of the root surface area in these teeth. Infiammatory resorption occurred in two experimental and three control teeth. These lesions, which were located either in the cervical region or near the apex, were filled with a cell-rich infiltrate and showed absence of repair. Persisting infiammatory reaction in the absence of resorption occurred in three experimental teeth (all in one animal) and one control tooth, either close to the root surface or more peripherally in the zone where reunion ofthe attachment apparatus presumably had taken place following replantation (Fig. 1)Ankylosis was recorded in 10 of 20 experimental teeth and in all 7 control teeth. The root surface area involved was significantly greater in the affected control teeth than in experimental teeth. Discussion
Fig. 1. Persisting inflammatory reaction 4 wk after delayed tooth replantation. Root surface was conditioned with 0.1% SnFi and \"Ai doxycycline HCl prior to replantation. A, diffuse inflammation which includes entire width of periodontal ligament. B, perivascular localization of inflammatory cells in peripheral portion of periodontal ligament. A, x 50; B, x 120.
The results once more confirmed the commonly reported finding that healing after replantation of avulsed teeth which have been dislocated for 45 min or more generally is complicated by ankylosis and root resorption (3-7). Approximately twothirds of the root surface area in the bench-dried control teeth showed such sequela 4 wk after replantation. However, this study also confirmed previous findings (9, 12, 18) that such unfavorable healing reactions can be significantly reduced, if not completely prevented, by suitable root surface conditioning. The biologic effects of SnF, and of tetracyclines on the root surface and adjacent soft tissues have been considered previously (12). This
2 and tetracycline in tooth replantation study confirms the conclusion that these substances may have a synergistic effect on the process of repair in replanted teeth. Most significantly, the amount of persisting inflammatory reaction in the gingiva and periodontal ligament adjacent to the root surface of the replanted teeth was negligible, and strikingly less than observed in the preceding study (12). Although biologic differences between the two sets of experimental animals and other variations between the studies cannot be ruled out, it appears that this difference is primarily a consequence of reducing the concentration of the SnFj solution from 1.0% to 0.1%. Inflammatory resorption was not a common finding and, when present, occurred in the cervical region or near the root apex. It is likely that several of these lesions had been induced by the specific damage to the root surface and adjacent soft tissue incurred during tooth extraction. This is supported by observations in the fractured, non-extracted teeth which also showed extensive inflammatory resorption cervically. While surface resorption is considered an inconsequential sequel of healing, ankylosis has been assumed to be progressive and, therefore, of greater prognostic concern. Thus, the number of ankylosis-free teeth may be of greater interest than the exact percentage of root surface area involved at any arbitrarily selected time point. On this basis, the 0.1% SnFj solution was considerably less effective than 1.0% SnF, in preventing ankylosis, as 10 of 20 teeth were affected, compared to no ankylosis in the preceding study (12). This was a short-term experiment. Interpretation of the results in terms of long-term survival rate of the replanted teeth or extrapolation to a clinical situation seems precarious. However, this and preceding experimental studies have repeatedly shown that root surface conditioning with SnF, followed by tetracycline may significantly improve the histologic healing result after delayed replantation. The question of whether complete, uncomplicated healing can be achieved by the selection of optimal root surface conditioning agents, concentrations, and application periods needs further investigation.
References 1. ANDREASEN J O , HJORTING-HANSEN
KoRNELiussEN for excellent histotechnical assistance.
E . Replantadon
of
teeth. I. Radiographic and clinical study of 110 human teeth replanted after accidental loss. Acta Odontol Scand 1966; 24: 263-84. 2. ANDREASEN JO. Etiology and pathogenesis of traumatic dental injuries. A clinical study of 1,298 cases. Scand J Dent Res 1970; 78: 329^2. 3. LoE H, WAERHAUG J. Experimental replantation of teeth in dogs and monkeys. Arch Oral Biol 1961; 3: 176-84. 4. BARBAKOW F H , CLEATON-JONES PE. Experimental replan-
tation of root-canal-filled and untreated teeth in the vervet monkey. / Etidod 1977; 3: 89-93. 5. SoDER PO, OTTESKOG P, ANDREASEN JO, MODEER T Effect
6. 7.
8. 9.
of drying on viability of periodontal membrane. Scand J Dent Res \911- 85: 164-8. ANDREASEN JO. Periodontal healing after replantation and autotransplantadon of incisors in monkeys. Int J Oral Surg 1981; 10: 54-61. ANDREASEN JO. Effect of extra-alveolar period and storage media upon periodontal and pulpal healing after replantation of mature permanent incisors in monkeys. //)/ J Oral Surg 1981; 10:43-53. ScHULMAN LB, KALIS P, GOLDHABER P. Eluoride inhibition of tooth-replant root resorption in cebus monkeys. J Oral Ther Pharmacol 1968; 4: 331 (only). BJORVATN K, MASSLER M . Effect of fluorides on root resorption in replanted rat molars. Acta Odontol Scand 1971; 29: 17-30.
10. BARBAKOW FH, AUSTIN JC, CLEATON-JONES PE. Histologic
response of replanted teeth pretreated with acidulated sodium nuoride. Oral Surg Oral Med Oral Pathol 1978; 45: 621-8. 11. MAHAJAN S K , SIDHU SS. Effect of fluoride on root resorption of autogenous dental replants. Clinical study. Aust £)e«r/1981; 26: 42-5. 12. BJORVATN K, SELVIG K A , KLINGE B. Effect of tetracycline
and SnF- on root resorption in replanted incisors in dogs. Scatid J Dent Res 1989; 97: 477-82. 13. SELVIG KA, BJORVATN K , CLAFFEY N . Effect of stannous
14.
15.
16.
17. 18.
Acknowledgments - To Ms. RITA ERIKSEN and Ms. EVA N .
203
fluoride and tetracycline on repair after delayed replantation of root-planed teeth in dogs. Acta Odontol Scatid 1990; 48: 107-12. ANDREASEN JO. A time-related study of periodontal healing and root resorption activity after replantation of mature permanent incisors in monkeys. Swed Dent J 1980; 4: 101-10. ANDREASEN JO. Analysis of pathogenesis and topography of replacement root resorption (ankylosis) after replantation of mature permanent incisors in monkeys. Swed Dent J 1980; 4: 321-40. ANDREASEN JO, KRISTERSON L. The effect of limited drying or removal of the periodontal ligament. Periodontal healing after replantation of mature permanent incisors in monkeys. Acta Odontol Scand 1981; 39: 1-13. ANDREASEN JO. The effect of splinting upon periodontal healing after replantation of permanent incisors in monkeys. Acta Odontol Scand 1975; 33: 313-23. BJORVATN K, WEISS MB. Effect of topical application of fluoride, cortisone and tetracycline on reimplanted rat molars. Fasett (Bergen) 1971; 1: 27-31.
Knut A. Selvig\ Kjell Bjorvatn\ Gary C. Bogle^ and Ulf M. E. Wikesjo' 'School of Dentistry, University of Bergen, Bergen, Norway and ^School of Dentistry, Loma Linda University, Loma Linda, California, USA
Selvig KA, Bjorvatn K, Bogle GC, Wikesjo UME: Effect of stannous fluoride and tetracycline on periodontal repair after delayed tooth replantation in dogs. Scand f Dent Res 1992; 100: 200-3. Previous studies have indicated that inflammatory resorption and ankylosis, which are frequent sequela after delayed tooth replantation, can be greatly reduced by treating the root surface with 1% solutions of stannous fluoride and tetracycline. However, the SnF, conditioning leaves a long-standing inflammatory reaction in the periodontal ligament. To examine whether a more dilute SnF2 solution would reduce postoperative inflammation without jeopardizing any beneficial effects, anterior teeth in three young adult beagles were extracted and allowed to air-dry for 45 min. They were then immersed in 0.1% SnFj for 5 min, rinsed in saline, immersed in 1% doxycycline HCl for 5 min, rinsed, and replanted. Control teeth were air-dried and replanted without further treatment. Block biopsies were harvested after 4 wk of healing and processed for histometric analysis. In experimental teeth, 85% of the root surface area showed normal healing, compared to 33% in control teeth. Conversely, resorption and ankylosis were more frequent in controls than in experimental teeth. A persisting inflammatory reaction either adjacent to or at a distance from the root surface was seen in limited areas in both experimental and control teeth. Compared to preceding studies, the fmdings indicate that reducing the strength of the SnFj solution from 1% to 0.1% may result in less persistent inflammation, at the cost, however, of less complete prevention of inflammatory resorption and ankylosis.
Clinical observations and experimental studies in dogs and primates have indicated that teeth replanted shortly after traumatic or experimental avulsion may heal with complete restoration of the periodontal structures (1, 2). On the other hand, teeth that have been exarticulated over a longer period of time show an increased tendency toward ankylosis and resorption (3-7). Soaking bench-dried teeth in a solution of either sodium fluoride or stannous fluoride prior to replantation has been shown to reduce the frequency of ankylosis and resorption (8, 9). These findings, however, are not unequivocal. Other studies have reported that pretreatment of roots with either neutral or acidulated sodium fluoride does not reduce root resorption and ankylosis (10, 11). The lack of agreement in these early studies may indicate that not only the fluoride ion, but also the cation in-
Key vi/ords: fluorides; tetracyciine; tooth reimplantation; traumatology, dental Knut A. Seivig, Department of Dental Research, University of Bergen Schooi of Dentistry, Arstadveien 17, N-5009 Bergen, Norvi^ay Accepted for publication 23 August 1991
volved and the pH ofthe solution, should be taken into consideration. While treatment with stannous fluoride may prevent root resorption in a short-term experiment, it also seems to delay resolution of the inflammatory phase of healing in the gingiva and periodontal ligament (12). If the stannous fluoride treatment is followed by immersion of the root in doxycycline, however, this adverse reaction is greatly diminished (12, 13). In a previous study of healing following delayed replantation, root surfaces were treated with 1% stannous fluoride followed by 1% doxycychne hydrochloride (12). This resulted in a dramatic reduction in the amount of root resorption compared to no treatment or doxycycline alone. Significantly, ankylosis did not occur. However, the specimens showed a high frequency of inflammatory reaction
2 and tetracyeline in tooth replantation in the periodontal ligament in the absence of resorption. The long-standing inflammatory reaction is presumably an effect of the stannous fluoride rather than of the tetracyeline treatment. In the present study, therefore, the concentration of the stannous fluoride solution was reduced from 1.0% to 0.1% in an attempt to reduce the inflammatory reaction. Material and methods Animals - The maxillary first and second incisors (II and 12) and mandibular first, second, and third incisors (II, 12, and 13) in three young adult beagle dogs were available for experimentation. In one of the dogs, three teeth fractured during extraction and were excluded from the study. The roots of these teeth, as well as the unoperated maxillary third incisors, remained in the jaws and were present in the histologic sections. Since previous studies (8, 9, 12) have shown a consistent healing result following delayed tooth replantation and, thus, may be regarded as the basis for this experimental study, only one quadrant in each animal was designated as a control, while three quadrants were used for the experimental procedure. The distribution of the experimental and control teeth is shown in Table 1. Experimental procedures ~ General anesthesia was accomplished by intravenous administration of pentobarbital sodium. The designated teeth were carefully extracted with forceps or elevators. The teeth were rinsed in saline, wiped dry, placed on filter paper, and left to dry on the bench for 45 min. The experimental teeth were then immersed in a 0.1% aqueous solution of SnF, for 5 min, rinsed briefly in sterile saline, immersed in 1% doxycycline HCI for 5 min, rinsed in saline, and replanted. Root surface instrumentation was not carried out. Control teeth were bench-dried for 45 min and then replanted without any root surface conditioning. The teeth were reseated in the alveolus, using gentle finger pressure. No fixation was used. Each animal received a single dose of penicillin + dihydrostreptomycin (Combiotic, Pfizer, Inc., NY) intramuscularly immediately after surgery. The dogs were fed a standard laboratory diet of soft consistency for 4 wk and were then sacrificed by intrave-
Table 1
'
Distribution of experimental teeth by animal and treatment procedure D 1 D2 D 3 12*11* 11 12 12 11 11 12 12 11 P 13 12 11 11 12 13 13*I2*I1* 11 12 13 13*12* 12 13 * Controls.
201
nous administration of sodium pentobarbital. A healing period of 4 wk was chosen to coincide with that of the preceding study (12). Previous experience with this model has indicated that, within this time period, pulpal necrosis, if occurring, will not have affected the healing response in the periapical region. The experimental protocol was approved by the institutional committee for animal experimentation. Specimen preparation - Anterior portions of the maxilla and mandible were removed, divided into right and left halves, fixed in 10% buffered formalin, demineralized in 5% formic acid, and embedded in paraffin wax. Horizontal sections were made at 7 iim through the incisor roots. Owing to the nonparallelism of the long axes of the iticisors, the resulting sections did not strictly represent transverse sections of all teeth in each block. The difference in angulation of the sections, however, was not considered to influence significantly the evaluation of the experimental results. Sections were stained with hematoxylin-eosin. Histometric analysis - Histologic evaluation of healing was carried out for each tooth separately. One section per 0.5 mm of root length was selected for histometric analysis. In each section, healing was examined at 12 points along the root surface, separated by an angle of 30° through the center of the tooth (14-16). At each measuring point, the presence of surface resorption, infiammatory resorption, ankylosis (replacement resorption), and inflammatory reaction without resorption was recorded. Each healing result was further categorized as active, arrested, or repaired, as appropriate (17). The absence of such sequela was recorded as uncomplicated healing. Eor each tooth, the proportion of the root surface showing the different healing results was calculated and expressed as a percentage. Statistical analysis included calculation of the means and standard deviations for experimental and control teeth. Whenever appropriate, the significance level of observed differences was evaluated by the Wilcoxon two-sample rank-sum test. Results
•
Clinically, all teeth healed uneventfully. No teeth were lost in the postoperative period. The histologic and histometric evaluation in experimental and control teeth is shown in Table 2. Downgrowth of junctional epithelium along the root surface was negligible. Uncomplicated healing predominated in the experimental teeth while the control teeth showed significantly more surface resorption and ankylosis. Generally, all teeth in each group showed a consistent healing pattern itidependent of tooth posi-
202
Selvig et al.
Table 2 Histometric results. Tissue reaction bv treatment group in percent of available surface area (mean + SD) No. of Normal Inflammation Surface Inflammatory teeth Group healitig resorption without resorptioti resorption Ankylosis Control 7 32.6 + 3.8 29.2 + 20.5 0.5+1.4 37.2 + 21.4 0.5±0.6 Experimental 20 85.0 + 7.2 10.6±7.9 0.7+1.4 0.2 + 0.5 4.1+6.3 a* 0.001 0.05 n.s. n.s. 0.001 Wilcoxon two-sample rank-sum test.
tion or dog, as indicated by the relatively small standard deviations. An exception was the variable amount of surface resorption and ankylosis seen in the control teeth. This result was due to a high frequency of ankylosis (range 58-69% of the root surf'ace) and a limited amount of surface resorption (5-8%) in the control teeth in Dogs 1 and 2, while in Dog 3, the control teeth showed less ankylosis (15-23%) and more surface resorption (38-50%). At sites adjacent to overt ankylosis, it was sometimes difficult to differentiate between root surface
facing periodontal ligament and root surface facing a bone marrow space. This was probably the greatest single source of analytic error and may have resulted in some sites in ankylosis-affected teeth being recorded as showing uncomplicated healing or surface resorption which, in fact, were part of an ankylotic process. Further analysis showed that surface resorption defects, in the experimental as well as the control teeth, were mostly arrested or showed a variable amount of repair. Superficial resorption defects which appeared active were seen in 8 of 20 experimental teeth and in 4 of 7 control teeth and accounted for 0.5-2.8% of the root surface area in these teeth. Infiammatory resorption occurred in two experimental and three control teeth. These lesions, which were located either in the cervical region or near the apex, were filled with a cell-rich infiltrate and showed absence of repair. Persisting infiammatory reaction in the absence of resorption occurred in three experimental teeth (all in one animal) and one control tooth, either close to the root surface or more peripherally in the zone where reunion ofthe attachment apparatus presumably had taken place following replantation (Fig. 1)Ankylosis was recorded in 10 of 20 experimental teeth and in all 7 control teeth. The root surface area involved was significantly greater in the affected control teeth than in experimental teeth. Discussion
Fig. 1. Persisting inflammatory reaction 4 wk after delayed tooth replantation. Root surface was conditioned with 0.1% SnFi and \"Ai doxycycline HCl prior to replantation. A, diffuse inflammation which includes entire width of periodontal ligament. B, perivascular localization of inflammatory cells in peripheral portion of periodontal ligament. A, x 50; B, x 120.
The results once more confirmed the commonly reported finding that healing after replantation of avulsed teeth which have been dislocated for 45 min or more generally is complicated by ankylosis and root resorption (3-7). Approximately twothirds of the root surface area in the bench-dried control teeth showed such sequela 4 wk after replantation. However, this study also confirmed previous findings (9, 12, 18) that such unfavorable healing reactions can be significantly reduced, if not completely prevented, by suitable root surface conditioning. The biologic effects of SnF, and of tetracyclines on the root surface and adjacent soft tissues have been considered previously (12). This
2 and tetracycline in tooth replantation study confirms the conclusion that these substances may have a synergistic effect on the process of repair in replanted teeth. Most significantly, the amount of persisting inflammatory reaction in the gingiva and periodontal ligament adjacent to the root surface of the replanted teeth was negligible, and strikingly less than observed in the preceding study (12). Although biologic differences between the two sets of experimental animals and other variations between the studies cannot be ruled out, it appears that this difference is primarily a consequence of reducing the concentration of the SnFj solution from 1.0% to 0.1%. Inflammatory resorption was not a common finding and, when present, occurred in the cervical region or near the root apex. It is likely that several of these lesions had been induced by the specific damage to the root surface and adjacent soft tissue incurred during tooth extraction. This is supported by observations in the fractured, non-extracted teeth which also showed extensive inflammatory resorption cervically. While surface resorption is considered an inconsequential sequel of healing, ankylosis has been assumed to be progressive and, therefore, of greater prognostic concern. Thus, the number of ankylosis-free teeth may be of greater interest than the exact percentage of root surface area involved at any arbitrarily selected time point. On this basis, the 0.1% SnFj solution was considerably less effective than 1.0% SnF, in preventing ankylosis, as 10 of 20 teeth were affected, compared to no ankylosis in the preceding study (12). This was a short-term experiment. Interpretation of the results in terms of long-term survival rate of the replanted teeth or extrapolation to a clinical situation seems precarious. However, this and preceding experimental studies have repeatedly shown that root surface conditioning with SnF, followed by tetracycline may significantly improve the histologic healing result after delayed replantation. The question of whether complete, uncomplicated healing can be achieved by the selection of optimal root surface conditioning agents, concentrations, and application periods needs further investigation.
References 1. ANDREASEN J O , HJORTING-HANSEN
KoRNELiussEN for excellent histotechnical assistance.
E . Replantadon
of
teeth. I. Radiographic and clinical study of 110 human teeth replanted after accidental loss. Acta Odontol Scand 1966; 24: 263-84. 2. ANDREASEN JO. Etiology and pathogenesis of traumatic dental injuries. A clinical study of 1,298 cases. Scand J Dent Res 1970; 78: 329^2. 3. LoE H, WAERHAUG J. Experimental replantation of teeth in dogs and monkeys. Arch Oral Biol 1961; 3: 176-84. 4. BARBAKOW F H , CLEATON-JONES PE. Experimental replan-
tation of root-canal-filled and untreated teeth in the vervet monkey. / Etidod 1977; 3: 89-93. 5. SoDER PO, OTTESKOG P, ANDREASEN JO, MODEER T Effect
6. 7.
8. 9.
of drying on viability of periodontal membrane. Scand J Dent Res \911- 85: 164-8. ANDREASEN JO. Periodontal healing after replantation and autotransplantadon of incisors in monkeys. Int J Oral Surg 1981; 10: 54-61. ANDREASEN JO. Effect of extra-alveolar period and storage media upon periodontal and pulpal healing after replantation of mature permanent incisors in monkeys. //)/ J Oral Surg 1981; 10:43-53. ScHULMAN LB, KALIS P, GOLDHABER P. Eluoride inhibition of tooth-replant root resorption in cebus monkeys. J Oral Ther Pharmacol 1968; 4: 331 (only). BJORVATN K, MASSLER M . Effect of fluorides on root resorption in replanted rat molars. Acta Odontol Scand 1971; 29: 17-30.
10. BARBAKOW FH, AUSTIN JC, CLEATON-JONES PE. Histologic
response of replanted teeth pretreated with acidulated sodium nuoride. Oral Surg Oral Med Oral Pathol 1978; 45: 621-8. 11. MAHAJAN S K , SIDHU SS. Effect of fluoride on root resorption of autogenous dental replants. Clinical study. Aust £)e«r/1981; 26: 42-5. 12. BJORVATN K, SELVIG K A , KLINGE B. Effect of tetracycline
and SnF- on root resorption in replanted incisors in dogs. Scatid J Dent Res 1989; 97: 477-82. 13. SELVIG KA, BJORVATN K , CLAFFEY N . Effect of stannous
14.
15.
16.
17. 18.
Acknowledgments - To Ms. RITA ERIKSEN and Ms. EVA N .
203
fluoride and tetracycline on repair after delayed replantation of root-planed teeth in dogs. Acta Odontol Scatid 1990; 48: 107-12. ANDREASEN JO. A time-related study of periodontal healing and root resorption activity after replantation of mature permanent incisors in monkeys. Swed Dent J 1980; 4: 101-10. ANDREASEN JO. Analysis of pathogenesis and topography of replacement root resorption (ankylosis) after replantation of mature permanent incisors in monkeys. Swed Dent J 1980; 4: 321-40. ANDREASEN JO, KRISTERSON L. The effect of limited drying or removal of the periodontal ligament. Periodontal healing after replantation of mature permanent incisors in monkeys. Acta Odontol Scand 1981; 39: 1-13. ANDREASEN JO. The effect of splinting upon periodontal healing after replantation of permanent incisors in monkeys. Acta Odontol Scand 1975; 33: 313-23. BJORVATN K, WEISS MB. Effect of topical application of fluoride, cortisone and tetracycline on reimplanted rat molars. Fasett (Bergen) 1971; 1: 27-31.
