Evaluation of a one-appointment formocresol pulpectomy technique for primary molars.

The purpose of this study was to evaluate the relative amount of root resorption in nonvital primary teeth after treatment with a 1-appointment formocresol pulpectomy. Thirty-seven children ranging in age from 2 years, 10 months to 8 years, 10 months received 41 pulpectomies in nonvital primary molars. At an initial follow-up examination, 6-36 months posttreatment (mean = 21 months), 80.5% (33/41) of the pulpectomies were rated success based on clinical and radiographic criteria. The age of the patient, the time interval the treated tooth was in place, and the type of tooth, had no significant effect on the success of the pulpecto~ny. Teeth with successful pulpectomies had root resorption similar to their antimeres. Pulpectomies tended to have root resorption similar to contralateral pulpotomies. A second follow-up evaluation 5 years to 6 years, 10 months postoperatively (mean 70 months), involved 29 the 41 pulpectomies; 86.1% (25/29) were rated a success. The pulpectomized molars were not overretained and succedaneous premolars had a low incidence of hypoplasia (2/17). In almost one-half of the cases, the root canal filler (zinc-oxide eugenol) was retained in the gingival sulcus after the pulpectomized tooth exfoliated. Various authors have expressed the view that endodontic treatment of nonvital primary teeth is contraindicated. CohenI stated that primary teeth were not suitable for proper biomechanical endodontic procedures. Massler 2 felt that only the most dedicated of pediatric dentists should attempt endodontic procedures on primary teeth. Brauer 3 claimed that endodontic procedures were impractical in children. Several reports have c/aimed clinical success treating primary teeth with infected or necrotic pulps utilizing techniques essentially limited to the pulp chamber.47 These reports have discussed 1or 2-visit procedures wherein the infected primary tooth had a medicament placed in the pulp chamber, but With no attempt to treat the pulp tissue within the root canals. Claims of success have been based on the patient’s being free of pain and having no clinical signs of apical abscess formation. Little information was given about radiographic changes nor was mention made as to whether the treated teeth were overretained or exfoliated early as compared to contralateral teeth. A variety of pulpectomy techniques for primary teeth also have been reported involving mechanical debridement of the pulp chamber and root canals, followed by irrigation, drying of canals, and placement of a resorbable filling material. Rabinowitch published an extensively documented study of 1363 root canals on nonvital primary molars. ~ He reported that an average of 5.5 visits were required for nonperiapically involved teeth and 7.7 visits were required for teeth with periapical involvement. Starkey ~ utilized 3 appointments to instrument, medicate, and, if asymptomatic, fill the canals with "Oxpara" paste as far apically as possible. He has advocated passing root canal files beyond the apex of molars~ and other authors have advocated similar pulpectomy techniques, u13 Starkey also noted that a primary tooth with a successful pulpectomy usually will be overretained. ~4 A 1-appointment complete pulpectomy technique on 35 primary molars has been reported wherein the canals were filled with zinc oxide and eugenol (ZOE). is The investigation judged 29 of the 35 teeth successful from clinical and radiographic interpretations after an average time of almost 16 months. Unfortunately, no specific criteria for success were stated. PEDIATRIC DENTISTRY: June 1985Nol. 7 No. 2 123 Rifkin reported treating 45 abscessed primary molars and incisors in 2 visits with an iodoform camphorated paste. ~6 Preoperatively, some teeth had pathologic or physiologic root resorption, while others had perforations of the pulpal floor. In a 2-1/2 to 4-1/2 year follow-up report on 38 of these cases he found no enamel o:: morphologic .defects in succedaneous teeth, but 3 cases had 1 mm enamel white spots. 17 In 20 of the 38 cases the teeth exfoliated naturally, but no comparison of exfoliation time was made to that of the contralateral tooth. The purpose of the present study was to examine the success of a 1-appointment pulpectomy technique on primary molars and follow the treated molars to determine if they exfoliated normally or were overretained; to evaluate their root resorption compared to their contralateral molars; to determine if the ZOE root canal filler was resorbed; and to tabulate the prevalence of enamel defects in succedaneous premolars. Methods and Materials Forty-one nonvital primary molar teeth in 37 children (2 years, 10 months to 8 years, 10 months) were treated in 1976 and 1977 using a 1-appointment formocresol pulpectomy technique similar to that described by O’Riordan and Coll. ~s All teeth were slightly mobile or had a sinus tract. On entrance into the pulp chamber, these teeth demonstrated a purulent exudate throughout the pulp chamber or evidence of severe pulpal degeneration such as purulent exudate extending into one or more canals. Radiographically, approximately 80% of the teeth had evidence of furcation or periapical bone destruction. Pulpectomies were determined to be contraindicated when: 1. Primary molars were mobile vertically or displayed extensive furcation radiolucencies involving more than one-half of the root 2. Internal resorption or other radiographic signs of pathologic :oot resorption were present involving any more than the apical tip of the root 3. A firm apical stop resistance point could not be obtained with a size 40 file or smaller 4. The patient had a congenital heart defect or other severe systemic disease. The pulpectomy procedure involved filing the canals short of the apex to a resistance point with progressive file sizes up to a size 40 or smaller. Prior experience had shown that excessive root canal filler will be extruded beyond the apex when no resistance point is established. After using each size file, sodium hypochlorite was u~ed for canal irrigation. After the final irrigation, paper points were used to dry the canals. Paper points slightly moistened with Buckley’s formocresol then were placed in each canal for 5 rain. A thick mix of ZOE was condensed into the canals with root canal pluggers as described by Goerig and Camp. ~9 Total treatment time was approximately 30-45 min. All treatments were performed by the same investigator (JAC). Various clinical and radiographic criteria were used to evaluate the success of the pulpectomies. Clinically, a successful pulpectomy showed no mobility and resolution of a draining sinus tract within a month. In addition, the history was negative for pain, swelling, or redness of the mucosa. Pulpectomies were considered a radiographic success if they exhibited no pathologic bone or root resorption (Fig 1). If there had been a furcation or apical radiolucency, a successful pulpectomy had to show evidence of bone formation (Fig 2). The clinical success of each pulpectomy was judged by one of the investigators (JAC) during routine recall appointments. Pulpectomies were evaluated radiographically by 2 of the investigators (JAC, JSC) viewing the preoperative and postoperative films independently. There was a 92% interrater agreement. In cases of disagreement, the radiographs were reevaluated. If disagreement still existed, the lower of the two ratings was used. Pulpectomies judged to be radiographic failures showed pathologic bone or root resorption (Fig 3). The presence of a small amount of extruded filling material in a clinically successful tooth, without pathologic bone or root resorption, was not considered a failure. From the first posttreatment examination, an evaluation was made to determine if pulpectomized molar roots resorbed faster, slower, or at the same rate as contralateral molars without pulpectomies. In 15 children, the contralateral molar had a carious pulp exposure, but no clinical or radiographic signs of pulpal necrosis, and a 1-step, 5-min formocresol pulpotomy was completed. The pulpectomy root resorption was evaluated independently by the 2 investigators (JAC, JSC) as having equal, more, or less root resorption than its contralateral molar. In cases of disagreement, the root resorption was rated the lower of the 2 rankings. Various factors including the patient’s age and sex, time interval the treated tooth was in place, and type of molar treated were tested using a chi square analysis to determine if they affected the success of pulpectomies. Results were judged significant at p = .05. The second posttreatment examination, which occurred 5 years or more following the initial therapy, assessed the exfoliation of the pulpectomized tooth and the success of the procedure. The same criteria for pulpectomy success were used. In addition, fac124 FORMOCRESOL PGLPECTOMY TECHNIQUE PRIMARY MOLARS: Coil et al. FIG 1. An example of a successful pulpectomy in a mandibular second molar showing no pathologic root resorption: A. (left) preoperative film, patient age 5 years; B. (center left) 16 months postoperative film; C. (center right) 5 years, 5 months postoperative film showing exfoliation of pulpectomy; D. (right) 6 years postoperative film of erupted premolar. It had no signs of hypoplasia and erupted within a few months of the contralateral premolar. FIG 2. An example of typical bone fill in a successful pulpectomy. The tooth previously had a pulpotomy which had failed. A. (left) Preoperative film, patient age 5 years; B. (center) Immediate postoperative film; C.(right) 8 months postoperative film showing bone fill. ____ TABLE 1. Patient Age of at Time of Pulpectomy Procedure Age Rating at Initial Exam Failure Success 0-4 yr