180
Periodontal Repair in Dogs: Effect of Root Surface Treatment With Stannous Fluoride or Citric Acid on Root Resorption Ulf
. E.
Wikesjö, * Noel Claffey, *f Rolf Nilvéus, ** and Jan Egelberg, **
This
study evaluated healing, with emphasis on root résorption, following root surface treatment with 1% aqueous stannous fluoride (SnF2), saturated citric acid (CA), or saline control (C) in conjunction with periodontal flap surgery. Supraalveolar periodontal defects were surgically created and immediately treated in the mandibular premolare in 6 beagle dogs. The defect height approximated 5 to 6 mm from the reduced alveolar bone to the cemento-enamel junction. Root treatments were rotated between experimental teeth within jaw quadrants and duplicated in left and right quadrants in the dogs. Flaps were raised to cover most of the crowns of the teeth and sutured. The dogs were sacrificed 12 weeks after surgery and tissue blocks with teeth and adjacent structures were processed for histometric analysis. SnF2-treated teeth healed with significantly longer junctional epithelium, less connective tissue repair to the root surface, and less bone regeneration than CA and C-treated teeth. New cementum formation was limited in all treatment groups. Root résorption was observed in almost all teeth exhibiting connective tissue repair, however to a lesser amount and not as frequent in SnF2 treated teeth due to limited connective tissue repair. No differences were found in amount and frequency of root résorption in CA and C-treated teeth. An inhibitory effect on root résorption of SnF2 could not be disclosed in this experiment, however, it may be concluded that CA treatment of the root surface in conjunction with reconstructive periodontal flap surgery does not seem to enhance root résorption. J Periodontal 1991; 62:180-184.
Key Words: Gingival histology; surgical flaps; epithelial attachment; tooth résorption; tooth root; stannous fluoride; citric acid.
résorption to be a significant sequel periodontal healing in experimental animals.1-11 In reconstructive periodontal flap surgery, the résorption process seems correlated to the amount of connective tissue repair to the root surface; periodontal defects with extensive repair frequently exhibit résorption.8,9 Although histological evidence exists of root résorption following reconstructive surgery in humans,12-14 this aberrant healing event seems rare.15-19 The observed, or perceived, absence of résorption may be a reflection of a generally Several reports have demonstrated root to
limited new connective tissue attachment to the root surface
following today's regenerative procedures. Extensive root résorption is, on the other hand, a frequent observation in periodontal healing following replantation of teeth.20 As new regenerative treatments develop, which may *School of
Linda University, Loma Ireland. National Dental Health Service, Sweden.
Dentistry, Loma
"Trinity College, Dublin,
Linda, CA.
result in substantial repair of periodontal defects, the experience from replanted teeth may indicate that root résorption may also impose a significant problem to improved regenerative procedures. Thus, further study seems necessary to understand the biology of repair in periodontal defects and the résorption process as well as the evaluation of agents that potentially may block this undesirable sequel of healing. Recent data suggest a potential role for stannous fluoride in suppression of root résorption. Application of stannous fluoride alone or in combination with tetracycline to root surfaces prior to replantation of extracted teeth seems to reduce the résorption process.21,22 However, tetracycline treatment alone does not seem to prevent résorption from occurring.9,21,23 Thus, the résorption suppressing action seems to rest with the stannous fluoride agent. Root surface treatment with acidic agents such as citric acid or tetracycline may likely be an important component of a reconstructive periodontal treatment protocol.5,7-9,24-26
Volume 62 Number 3
WIKESJÖ, CLAFFEY, NILVÉUS, EGELBERG
Table 1: Distribution of Root Surface Treatments Between Experimental Teeth (P2, P3, and P4) Repeated in Left and Mandibular Jaw Quadrants in Subsequent Dogs
Dog 1 2 3 4 5 6
Stannous Fluoride P2 P2
Citric Acid P3 P3
P4 P4 P3 P3
P2 P2 P4 P4
Right
Saline Control P4 P4 P3 P3 P2 P2
Root résorption has often been observed following citric acid treatment in conjunction with reconstructive surgery.7-9'27-29 It has been suggested that this effect relates to the extensive connective tissue repair to the root surface found in citric-acid treated defects.8'9 However, it has also been suggested that the citric acid treatment actually may enhance the résorption process.29 Since stannous fluoride treatment was tested in replanted teeth21,22 and the evaluation of résorption following citric acid treatment was made in periodontal fenestration defects,29 it was decided to further evaluate these treatments in conjunction with reconstructive periodontal flap surgery. Healing following stannous fluoride and citric acid treatments was
compared
saline control. surgically created and fects in dogs.
with
a
healing following root treatment Experimentation was carried out in immediately treated periodontal de-
to
MATERIALS AND METHODS Animals and Surgical Procedures Six young adult male beagle dogs were used. Bilateral supraalveolar periodontal defects were surgically created around the 2nd, 3rd and 4th mandibular premolars (P2, P3 and P4) immediately followed by reconstructive surgery as earlier described.11 The defects measured approximately 5 to 6 mm
from the cemento-enamel junction (CEJ) to the margin of the reduced alveolar bone. All surgical procedures were performed under sodium pentobarbital anesthesia. The dogs received lactated Ringer's solution intravenously during surgery. A soft dog food diet was used throughout the study. This study was part of an institutionally approved protocol in periodontal wound healing in dogs.
Wound Management The root surfaces were instrumented to remove all cementum. The experimental teeth within each jaw quadrant were isolated, one after the other, with a rubber dam and the isolated root surfaces treated with either a 1% stannous fluoride solution, a saturated citric acid solution, or a saline control (sterile, 0.9% NaCl). Root treatments were rotated between experimental teeth within jaw quadrants and duplicated in left and right quadrants in subsequent dogs (Table 1). The stannous fluoride was applied as a 5-minute continuous drop application. The citric acid solution was applied as a 3-minute continuous drop application. Follow-
181
ing this, the teeth were vigorously rinsed with sterile saline. The rubber dam was removed from each isolated premolar after treatment. At wound closure the periosteum was fenestrated at the base of the buccal and lingual flaps and the flaps were coronally elevated and sutured to cover most of the teeth but the cusp tips. Vertical mattress sutures were used interdentally and at the mesial and distal extent of the wounds. Single interrupted sutures were used as necessary to complete closure of the wound. Care was exercised to proximate the connective tissue surfaces of the buccal and lingual flaps at wound closure. Sutures were removed after 7 to 10 days. A broad spectrum antibiotic§ was administered intramuscularly daily the first 2 weeks following surgery. Daily plaque control was achieved by gently wiping the teeth, as they became exposed, with gauze soaked in a 2% Chlorhexidine solution11 for the duration of the study. The dogs were sacrificed by intravenous injection of concentrated sodium pentobarbital 12 weeks after surgery. Histological
Procedures Block biopsies including experimental teeth and surrounding soft and hard tissues were obtained at sacrifice. The blocks were decalcified, trimmed, dehydrated, and embedded in paraffin. Serial sections, 7 µ thick, were cut in a bucco-lingual plane throughout each tooth. Every 14th section, approximately 100 µ apart, was stained with Masson's trichrome and an adjacent section with hematoxylin and eosin. Judged by the size of the root canal and the pulp chamber, the most central stained section was identified for both the mesial and the distal root. This section and the 2 step serial sections on each side stained with Masson's trichrome were used for analysis. New cementum formation was also confirmed from adjacent hematoxylin and eosin stained sections. Measurements were performed at approximately 30 x magnification using a microscope linked to a computer aided manual data collection system.11 The following measurements were taken for the buccal and lingual surfaces of each root of the teeth: Defect height: the distance between the apical extension of the root planing and the cemento-enamel junction. Junctional epithelium: the distance from apical to the coronal extension of the junctional epithelium along the root surface. Connective tissue repair: the distance between the apical extension of the root planing and the apical termination of the junctional epithelium. Cementum formation: the distance between the apical extension of the root planing and the coronal extension of a continuous layer of cementum or a cementum-like deposit on the root surface. Bone formation : the distance between the apical exten§Combiotic, Pfizer Inc, New York, NY. iHibitane, ICI Ltd, Macclesfield, Great Britain. 1Videoplan, Carl Zeiss Inc, Kontron, Eching bei München, Germany.
J Periodontol March 1991
PERIODONTAL REPAIR IN DOGS
182
Table 2: Histometric Analysis of Repair in Supraalveolar Periodontal Defects. The Root Surfaces in These Defects Were Treated with Stannous Fluoride or Citric Acid or a Saline Control. = 6 Means ± s.d. in mm, dogs Citric Acid
Stannous Fluoride
Defect height Junctional epithelium
5.5±0.6 5.4±1.0 5.2±0.6 4.0±0.4— -0.9±0.9— -2.5±1.8
Connective tissue
0.3±0.3— -4.5±0.9— -2.8±1.7
repair
Cementum formation Bone formation Root
résorption
Ankylosis :
Periodontal Repair in Dogs: Effect of Root Surface Treatment With Stannous Fluoride or Citric Acid on Root Resorption Ulf
. E.
Wikesjö, * Noel Claffey, *f Rolf Nilvéus, ** and Jan Egelberg, **
This
study evaluated healing, with emphasis on root résorption, following root surface treatment with 1% aqueous stannous fluoride (SnF2), saturated citric acid (CA), or saline control (C) in conjunction with periodontal flap surgery. Supraalveolar periodontal defects were surgically created and immediately treated in the mandibular premolare in 6 beagle dogs. The defect height approximated 5 to 6 mm from the reduced alveolar bone to the cemento-enamel junction. Root treatments were rotated between experimental teeth within jaw quadrants and duplicated in left and right quadrants in the dogs. Flaps were raised to cover most of the crowns of the teeth and sutured. The dogs were sacrificed 12 weeks after surgery and tissue blocks with teeth and adjacent structures were processed for histometric analysis. SnF2-treated teeth healed with significantly longer junctional epithelium, less connective tissue repair to the root surface, and less bone regeneration than CA and C-treated teeth. New cementum formation was limited in all treatment groups. Root résorption was observed in almost all teeth exhibiting connective tissue repair, however to a lesser amount and not as frequent in SnF2 treated teeth due to limited connective tissue repair. No differences were found in amount and frequency of root résorption in CA and C-treated teeth. An inhibitory effect on root résorption of SnF2 could not be disclosed in this experiment, however, it may be concluded that CA treatment of the root surface in conjunction with reconstructive periodontal flap surgery does not seem to enhance root résorption. J Periodontal 1991; 62:180-184.
Key Words: Gingival histology; surgical flaps; epithelial attachment; tooth résorption; tooth root; stannous fluoride; citric acid.
résorption to be a significant sequel periodontal healing in experimental animals.1-11 In reconstructive periodontal flap surgery, the résorption process seems correlated to the amount of connective tissue repair to the root surface; periodontal defects with extensive repair frequently exhibit résorption.8,9 Although histological evidence exists of root résorption following reconstructive surgery in humans,12-14 this aberrant healing event seems rare.15-19 The observed, or perceived, absence of résorption may be a reflection of a generally Several reports have demonstrated root to
limited new connective tissue attachment to the root surface
following today's regenerative procedures. Extensive root résorption is, on the other hand, a frequent observation in periodontal healing following replantation of teeth.20 As new regenerative treatments develop, which may *School of
Linda University, Loma Ireland. National Dental Health Service, Sweden.
Dentistry, Loma
"Trinity College, Dublin,
Linda, CA.
result in substantial repair of periodontal defects, the experience from replanted teeth may indicate that root résorption may also impose a significant problem to improved regenerative procedures. Thus, further study seems necessary to understand the biology of repair in periodontal defects and the résorption process as well as the evaluation of agents that potentially may block this undesirable sequel of healing. Recent data suggest a potential role for stannous fluoride in suppression of root résorption. Application of stannous fluoride alone or in combination with tetracycline to root surfaces prior to replantation of extracted teeth seems to reduce the résorption process.21,22 However, tetracycline treatment alone does not seem to prevent résorption from occurring.9,21,23 Thus, the résorption suppressing action seems to rest with the stannous fluoride agent. Root surface treatment with acidic agents such as citric acid or tetracycline may likely be an important component of a reconstructive periodontal treatment protocol.5,7-9,24-26
Volume 62 Number 3
WIKESJÖ, CLAFFEY, NILVÉUS, EGELBERG
Table 1: Distribution of Root Surface Treatments Between Experimental Teeth (P2, P3, and P4) Repeated in Left and Mandibular Jaw Quadrants in Subsequent Dogs
Dog 1 2 3 4 5 6
Stannous Fluoride P2 P2
Citric Acid P3 P3
P4 P4 P3 P3
P2 P2 P4 P4
Right
Saline Control P4 P4 P3 P3 P2 P2
Root résorption has often been observed following citric acid treatment in conjunction with reconstructive surgery.7-9'27-29 It has been suggested that this effect relates to the extensive connective tissue repair to the root surface found in citric-acid treated defects.8'9 However, it has also been suggested that the citric acid treatment actually may enhance the résorption process.29 Since stannous fluoride treatment was tested in replanted teeth21,22 and the evaluation of résorption following citric acid treatment was made in periodontal fenestration defects,29 it was decided to further evaluate these treatments in conjunction with reconstructive periodontal flap surgery. Healing following stannous fluoride and citric acid treatments was
compared
saline control. surgically created and fects in dogs.
with
a
healing following root treatment Experimentation was carried out in immediately treated periodontal de-
to
MATERIALS AND METHODS Animals and Surgical Procedures Six young adult male beagle dogs were used. Bilateral supraalveolar periodontal defects were surgically created around the 2nd, 3rd and 4th mandibular premolars (P2, P3 and P4) immediately followed by reconstructive surgery as earlier described.11 The defects measured approximately 5 to 6 mm
from the cemento-enamel junction (CEJ) to the margin of the reduced alveolar bone. All surgical procedures were performed under sodium pentobarbital anesthesia. The dogs received lactated Ringer's solution intravenously during surgery. A soft dog food diet was used throughout the study. This study was part of an institutionally approved protocol in periodontal wound healing in dogs.
Wound Management The root surfaces were instrumented to remove all cementum. The experimental teeth within each jaw quadrant were isolated, one after the other, with a rubber dam and the isolated root surfaces treated with either a 1% stannous fluoride solution, a saturated citric acid solution, or a saline control (sterile, 0.9% NaCl). Root treatments were rotated between experimental teeth within jaw quadrants and duplicated in left and right quadrants in subsequent dogs (Table 1). The stannous fluoride was applied as a 5-minute continuous drop application. The citric acid solution was applied as a 3-minute continuous drop application. Follow-
181
ing this, the teeth were vigorously rinsed with sterile saline. The rubber dam was removed from each isolated premolar after treatment. At wound closure the periosteum was fenestrated at the base of the buccal and lingual flaps and the flaps were coronally elevated and sutured to cover most of the teeth but the cusp tips. Vertical mattress sutures were used interdentally and at the mesial and distal extent of the wounds. Single interrupted sutures were used as necessary to complete closure of the wound. Care was exercised to proximate the connective tissue surfaces of the buccal and lingual flaps at wound closure. Sutures were removed after 7 to 10 days. A broad spectrum antibiotic§ was administered intramuscularly daily the first 2 weeks following surgery. Daily plaque control was achieved by gently wiping the teeth, as they became exposed, with gauze soaked in a 2% Chlorhexidine solution11 for the duration of the study. The dogs were sacrificed by intravenous injection of concentrated sodium pentobarbital 12 weeks after surgery. Histological
Procedures Block biopsies including experimental teeth and surrounding soft and hard tissues were obtained at sacrifice. The blocks were decalcified, trimmed, dehydrated, and embedded in paraffin. Serial sections, 7 µ thick, were cut in a bucco-lingual plane throughout each tooth. Every 14th section, approximately 100 µ apart, was stained with Masson's trichrome and an adjacent section with hematoxylin and eosin. Judged by the size of the root canal and the pulp chamber, the most central stained section was identified for both the mesial and the distal root. This section and the 2 step serial sections on each side stained with Masson's trichrome were used for analysis. New cementum formation was also confirmed from adjacent hematoxylin and eosin stained sections. Measurements were performed at approximately 30 x magnification using a microscope linked to a computer aided manual data collection system.11 The following measurements were taken for the buccal and lingual surfaces of each root of the teeth: Defect height: the distance between the apical extension of the root planing and the cemento-enamel junction. Junctional epithelium: the distance from apical to the coronal extension of the junctional epithelium along the root surface. Connective tissue repair: the distance between the apical extension of the root planing and the apical termination of the junctional epithelium. Cementum formation: the distance between the apical extension of the root planing and the coronal extension of a continuous layer of cementum or a cementum-like deposit on the root surface. Bone formation : the distance between the apical exten§Combiotic, Pfizer Inc, New York, NY. iHibitane, ICI Ltd, Macclesfield, Great Britain. 1Videoplan, Carl Zeiss Inc, Kontron, Eching bei München, Germany.
J Periodontol March 1991
PERIODONTAL REPAIR IN DOGS
182
Table 2: Histometric Analysis of Repair in Supraalveolar Periodontal Defects. The Root Surfaces in These Defects Were Treated with Stannous Fluoride or Citric Acid or a Saline Control. = 6 Means ± s.d. in mm, dogs Citric Acid
Stannous Fluoride
Defect height Junctional epithelium
5.5±0.6 5.4±1.0 5.2±0.6 4.0±0.4— -0.9±0.9— -2.5±1.8
Connective tissue
0.3±0.3— -4.5±0.9— -2.8±1.7
repair
Cementum formation Bone formation Root
résorption
Ankylosis :
