Success or failure of endodontic treatments: A retrospective study.

CONTEXT: Well-conducted endodontic therapy is necessary for the dental rehabilitation of the individuals with cleft lip and palate. AIM: The aim of this study was to verify the success and failure index of endodontic treatments performed in the Endodontic Sector of the Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, (HRAC/USP), Bauru, Brazil.
MATERIALS AND METHODS: The preservation records (at least 2 years) of the endodontic treatments performed in the HRAC/USP were verified, indicating the success or failure of the treatment, and these treatments were divided into three groups (vital pulp, necrotic pulp, and endodontic retreatment). The Chi-square statistical test was applied with a significance level of 5%.
RESULTS: A total of 1216 endodontic treatments were quantified with a minimum of 2 years of prenatal care at HRAC/USP. The vital pulp group had a success rate of 99.4% (535 treatments) and 0.6% failure (3 treatments), 98.6% of success in the necrotic pulp group (577 treatments) and 1.4% failure (8 treatments), and 95.6% success rate (89 treatments) and 4.4% failure (4 treatments) in the endodontic reintervention group.
CONCLUSION: From the results found, we can conclude that there was a high success rate in the treatments and endodontic retreatments performed in the Endodontics Sector of the HRAC/USP, considering that well-conducted endodontic therapy is extremely important in the oral rehabilitation of individuals with cleft lip and palate.

INTRODUCTION

Pulp necrosis denotes the cessation of the metabolic processes of this tissue, with consequent loss of its structure, as well as its natural defenses. In these cases, the recommended endodontic treatment is known as necropulpectomy.[12]

Despite all the obstacles inherent in combating infection in the root canal system, studies show a high success rate of endodontic treatment: between 85 and 95%, especially in cases where endodontic treatment is necessary in vital pulp (biopulpectomy), where the infection is restricted to the pulp chamber.[345] Although endodontic treatment is a predictable procedure with high success rates, failures can occur either through persistent infection or through recontamination of the root canal system at some time after endodontic intervention.[67] There is an evidence in the literature demonstrating that the persistence of apical biofilm with areas of the bone resorption may be related to failure rates of endodontic therapy.[89]

Endodontic retreatment has lower success rates when compared to the treatment itself.[101112] In analyzing the success of the endodontic retreatment, a rate of approximately 66% was reported, and this index is lower compared to the high rates obtained with the treatments, indicating, in addition to the technical difficulties inherent to iatrogenic factors, the impossibility of eliminating microorganisms resistant to biomechanical preparation.[1314] The oral rehabilitation of individuals with cleft lip and palate is complex, extensive, and multidisciplinary and may require endodontic treatment, either by prosthetic purpose or by microbial etiology.[15]

Orofacial fissures represent the most prevalent craniofacial changes in humans, ranging from 1:500 to 1:2500 live births worldwide depending on the different ethnic groups (nonsyndromic), defect or in conjunction with other defects (syndromic).[1617181920]

When irreversible damage is caused to the pulp tissue, endodontic treatment should be performed to restore the masticatory functions and normal physiology of the tooth. Moreover, if carefully planned, well executed, and with observance of the peculiarities of the dental element near the area of fissure, the treatment may lead to success, achieving the same percentage of success associated with endodontic treatments performed on nonfissured individuals.[2122]

Therefore, it is of interest to know the success index of the endodontic treatments performed in the individuals attended in the Endodontic Sector of the Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo (HRAC/USP), at the moment of the return to the preservation, collaborating for the quality control of the service to review the efficiency of its practices.

MATERIALS AND METHODS

The HRAC/USP Data Processing Center requested, after approval of the present study by the HRAC/USP's Human Research Ethics Committee under the number 59829916.0.0000.5441 the listing of individuals who performed the preservation of endodontic therapies in the last 2 years, and these records were selected, making a total of 1216 treatments derived from endodontic treatments and reinterventions, whose data were verified and recorded with respect to the success or failure of the treatment performed, thus, the data obtained were quantified and tabulated using the Microsoft Excel program. Chi-square statistical test, which was applied with a significance level of 5%.

According to the type of endodontic treatment performed, data from the present study were divided into three groups:

Group 1: Data obtained from the preservation of endodontically treated teeth with vital pulp

Group 2: Data obtained from the preservation of endodontically treated teeth with necrotic pulp

Group 3: Data obtained from the preservation of endodontically treated teeth that required endodontic retreatment.

Endodontic treatments of each group were quantified regarding their success or failure, taking into account the analysis performed and annotated in the medical records by the professional responsible for the care.

RESULTS

A total of 1216 endodontic preservations were quantified, of which 538 belonged to Group 1, 585 to Group 2, and 93 to Group 3.

The percentage of success and failure was verified according to the type of treatment performed; thus, Group 1 (endodontically treated teeth with vital pulp, biopulpectomy) had a success rate of 99.4% (535 treatments) and 0.6% of failure (3 treatments); Group 2 (endodontically treated teeth with necrotic pulp, necropulpectomy) had 98.6% success (577 treatments) and 1.4% failure (8 treatments); and Group 3 (endodontically treated teeth requiring endodontic retreatment) had 95.6% success (89 treatments) and 4.4% failure (4 treatments) [Figure 1].

Figure 1

Percentage of success according to the type of treatment performed. Group 1. Endodontically treated teeth with vital pulp (biopulpectomy); Group 2. Endodontically treated teeth with necrotic pulp (necropulpectomy); Group 3. Endodontically treated teeth that required endodontic retreatment (endodontic retreatment)

In relation to dental groups, the maxillary central incisors (teeth 11 and 21) had a higher number of observed tenderness and consequently a higher percentage of success [Table 1].

Table 1

Distribution of the dental groups referring to the clinical and radiograph follow-up verified and percentage of success of the same

Upper maxilla		Lower maxilla
Teeth	n (%)	Teeth	n (%)
Tooth 11	129 (10.6)	Tooth 31	25 (2.1)
Tooth 12	37 (3.0)	Tooth 32	14 (1.2)
Tooth 13	35 (2.9)	Tooth 33	17 (1.4)
Tooth 14	30 (2.5)	Tooth 34	18 (1.5)
Tooth 15	45 (3.7)	Tooth 35	27 (2.2)
Tooth 16	70 (5.8)	Tooth 36	83 (6.8)
Tooth 17	24 (2.0)	Tooth 37	26 (2.1)
Tooth 18	1 (0.1)	Tooth 38	4 (0.3)
Tooth 21	142 (11.6)	Tooth 41	20 (1.6)
Tooth 22	28 (2.3)	Tooth 42	10 (0.8)
Tooth 23	62 (5.1)	Tooth 43	7 (0.6)
Tooth 24	47 (3.9)	Tooth 44	30 (2.5)
Tooth 25	48 (3.9)	Tooth 45	36 (3.0)
Tooth 26	65 (5.3)	Tooth 46	72 (5.9)
Tooth 27	33 (2.7)	Tooth 47	28 (2.3)
Tooth 28	2 (0.2)	Tooth 48	1 (0.1)
Total	798 (65.6)	Total	418 (34.4)
Total teeth	1.216 (100)

DISCUSSION

The scientific technical advance in endodontics in the last years has been increasing the incidence of success of the treatment of root canals.[23] The absence of spontaneous and provoked painful symptomatology, hermetic sealing, dental element rehabilitated in masticatory function, and the repair of the apical and periapical tissues are clinical criteria of success in endodontic therapy.[24] When failure occurs, it is closely related to the persistence of microorganisms after endodontic obturation and/or infection due to lack of coronary sealing.[2325]

Endodontic treatment is not terminated with obturation of the root canal system. Clinical and radiographic control (preservation) is extremely important for the longevity of therapy; once any alteration is detected, endodontic retreatment is indicated, as long as it is able to be performed.[11]

The European Society of Endodontics (EUROPEAN SOCIETY OF ENDODONTOLOGY, 2006) suggests that radiographs of control should be taken for at least 1 year after the endodontic treatment is completed and that subsequent radiographs are taken, if necessary. In view of the difficulty of performing the histopathological analysis of the periapical lesion, clinical and radiographic preservation should be encouraged by the professional for the period of 2–4 years.[1226] In the present study, only endodontic treatments with at least 2 years of preservation period were included.

The success of endodontic treatment is closely related to the condition of the pulp tissue. In the radical treatment of inflamed vital pulp (biopulpectomy), the infection when present is restricted to the pulp chamber and cervical third. The root canal system and the periradicular tissues are not infected. Thus, a high success rate is found for endodontic treatments with vital pulp when compared to the treatments of necrotic pulp and retreatment.[27] This fact was verified in the present study where 99.4% (535 treatments) of success index was obtained and only 0.6% (3 treatments) of cases of failure in the group of teeth treated endodontically with vital pulp (biopulpectomies) (Group 1). In cases of necrotic pulp (necropulpectomy) and in cases of teeth that require endodontic retreatment, the success rate is decreased, since the professional must perform a biomechanical preparation with the purpose of eliminating the pathogenic microbiota from the canal system.[28] Numerous bacterial species have been detected in infected root canals and their elimination is not always achieved, culminating in the persistence of endodontic infection, resulting in failure of therapy.[25] In cases of endodontic retreatment, the success rate is even lower, since in addition to eliminating the microorganisms of the root canal system, it is fundamental to remove all existing obturator material and correction of possible-related iatrogenics.[293031] These data corroborate in with the results of the present study, where the percentage of success of the endodontic treatments in necrotic pulp and of the teeth that required endodontic retreatment were lower in comparison with the group of teeth treated in vital pulp. Nevertheless, the three groups analyzed had a high success rate. The Group 2 endodontically treated teeth with necrotic pulp (Necropulpectomy) achieved 98.6% success (577 treatments) and 1.4% failure (8 treatments), and the Group 3 endodontically treated teeth that required endodontic retreatment presented 95.6% success cases (89 treatments) and 4.4% of failure (4 treatments); 93 cases of endodontic retreatment were analyzed. It is believed that for all the difficulties inherent to endodontic retreatment, if more cases of this type were analyzed, we could find a lower success rate, although, we always aim for success.

The success of endodontic therapy is partly related to the knowledge of the internal dental anatomy and its variations.[32] The upper central incisors present a single root, usually straight, with a single and conical root canal.[33] Thus, the endodontic treatment of the upper central incisors most often occurs without intercurrences or iatrogenics, which justifies the highest percentage of successful cases (10.6% for the 11 tooth and 11.6% for the 21 tooth) compared to the other teeth, but we must take into account the fact that they were the cases of greater number of retention and, consequently, the expression of success.

CONCLUSION

The success index of the treatments or endodontic retreatments performed in the Endodontic Sector of the HRAC/USP is high, these data being of great relevance, since well-conducted endodontic therapy is necessary for the dental rehabilitation of the individuals with cleft lip and palate.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.