Clinical Results with Two Different Methods of Root-end Preparation and Filling in Apical Surgery: Mineral Trioxide Aggregate and Adhesive Resin Composite

Clinical Results with Two Different Methods of Root-end Preparation and Filling in Apical Surgery: Mineral Trioxide Aggregate and Adhesive Resin Composite

Clinical Research Clinical Results with Two Different Methods of Root-end Preparation and Filling in Apical Surgery: Mineral Trioxide Aggregate and A...

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Clinical Research

Clinical Results with Two Different Methods of Root-end Preparation and Filling in Apical Surgery: Mineral Trioxide Aggregate and Adhesive Resin Composite ¨ nni, Dr. med. dent.,† Thomas von Arx, Prof. Dr. med. dent.,* Stefan Ha ˚ rd Jensen, DDS*‡ and Simon Storga Abstract Introduction: The aim of apical surgery is to hermetically seal the root canal system after root-end resection, thereby enabling periradicular healing. The objective of this nonrandomized prospective clinical study was to report results of 2 different root-end preparation and filling methods, ie, mineral trioxide aggregate (MTA) and an adhesive resin composite (Retroplast). Methods: The study included 353 consecutive cases with endodontic lesions limited to the periapical area. Root-end cavities were prepared with sonic microtips and filled with MTA (n = 178), or alternatively, a shallow concavity was prepared in the cut root face, with subsequent placement of an adhesive resin composite (Retroplast) (n = 175). Patients were recalled after 1 year. Cases were defined as healed when no clinical signs or symptoms were present and radiographs demonstrated complete or incomplete (scar tissue) healing of previous radiolucencies. Results: The overall rate of healed cases was 85.5%. MTA-treated teeth demonstrated a significantly (P = .003) higher rate of healed cases (91.3%) compared with Retroplast-treated teeth (79.5%). Within the MTA group, 89.5%–100% of cases were classified as healed, depending on the type of treated tooth. In contrast, more variable rates ranging from 66.7%–100% were found in the Retroplast group. In particular, mandibular premolars and molars demonstrated considerably lower rates of healed cases when treated with Retroplast. Conclusions: MTA can be recommended for root-end filling in apical surgery, irrespective of the type of treated tooth. Retroplast should be used with caution for root-end sealing in apical surgery of mandibular premolars and molars. (J Endod 2010;36:1122–1129)

Key Words Apical surgery, clinical study, follow-up, MTA, Retroplast, root-end filling

O

ne of the objectives of apical surgery is to hermetically seal the root canal system after root-end resection, thereby enabling healing by forming a barrier between the irritants within the confines of the affected root and the periapical tissues. This seal is usually accomplished by root-end cavity preparation with subsequent root-end filling. Various techniques of root-end cavity preparation and a myriad of filling materials have been described in the past for use in apical surgery (1–3). Traditionally, rotary instruments were used to prepare a cavity at the cut root face after apical resection. In the early 1990s, the introduction of ultrasonic or sonic-driven microtips revolutionized the retrograde preparation technique. Other clinicians have advocated the use of files for retrograde instrumentation of root canals (4). Although all these preparation techniques aim at negotiating the root canal to a certain depth, the Retroplast technique uses a different approach. With this method, a shallow concavity is prepared by using a ball-shaped, diamond drill. The concavity encompasses the whole cut root face without perforation into the adjacent periodontal ligament space (5, 6). The concavity is eventually filled with Retroplast (a liquid composite material specifically developed for this purpose), which is placed after etching and application of a priming-bonding agent. Optimal hemorrhage control is paramount with this method. The rationale for using a dentin-bonded resin is to completely seal the cut root face, including patent dentin tubules, isthmuses, accessory canals, and the main root canal(s). Although the Retroplast technique has a long history since it was introduced in 1989 (5, 7), the use of mineral trioxide aggregate (MTA) as a retrograde filling material was first reported in 1999 (8). Recently, MTA has gained wide acceptance for pulp capping, apexification, closure of perforations, and root-end filling (9–11). However, only a few clinical studies have compared this material with other filling materials for retrograde filling in apical surgery (12–15). The purpose of this prospective clinical 1-year study was to report the healing outcomes of 2 different methods of root-end preparation and filling in apical surgery, MTA and an adhesive resin composite (Retroplast).

Materials and Methods Patient Selection Patients undergoing apical surgery from May 2001–August 2007 were consecutively enrolled. Patients were fully instructed about the surgical procedure, postoperative care, follow-up examinations, and alternative treatment options. Each patient signed a consent form according to the Declaration of Helsinki. For the present study, the following cases were excluded: teeth with through-and-through lesions, with root

From the )Department of Oral Surgery and Stomatology and †Department of Preventive, Pediatric, and Restorative Dentistry, School of Dental Medicine, University of Bern, Bern, Switzerland; and ‡Department of Oral & Maxillofacial Surgery, Copenhagen University Hospital, Copenhagen, Denmark. Address requests for reprints to Prof. Dr. T. von Arx, Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Freiburgstrasse 7, CH-3010 Bern, Switzerland. E-mail address: [email protected] 0099-2399/$0 - see front matter Copyright ª 2010 American Association of Endodontists. doi:10.1016/j.joen.2010.03.040

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Figure 1. Diagram showing the distribution of cases treated with MTA (n = 173) and Retroplast (n = 166) per 4-month term from 2001–2007 (I, 1st trimester of year; II, 2nd trimester of year; III, 3rd trimester of year).

perforations, or with apicomarginal lesions. In patients with multiple teeth undergoing apical surgery, only 1 tooth was selected for further analysis (randomization according to www.graphpad.com/ quickcalcs/randomize1.cfm). The included material comprised 353 teeth.

Surgical Technique Apical surgery was performed under local anesthesia (articaine 4% with 1:100,000 adrenaline, Ultracain 4% D-S forte; SanofisAventis, Meyrin, Switzerland) in an operating room and by using a surgical microscope (Mo¨ller Denta 300; Haag-Streit International, Ko¨niz, Switzerland). After the elevation of a full-thickness mucoperiosteal flap, osteotomy was carried out with round burs under copious saline irrigation. Affected roots were then resected approximately 3 mm from the apex. After debridement of the pathologic tissue, hemostasis of the

bony crypt was achieved with aluminum chloride (Expasyl; Produits Dentaires Pierre Rolland, Merignac, France) and/or ferric sulfate (Stasis; Belport Co, Camarillo, CA). After staining of the surgical area with methylene blue, the root end was inspected by using a rigid endoscope (TeleOtoscope; Karl Storz GmbH, Tuttlingen, Germany). Rootend cavities were prepared with sonic-driven microtips (KaVoSONICretro; KaVo Dental GmbH, Biberach, Germany) and were retrofilled with MTA (ProRoot; Dentsply Tulsa Dental, Tulsa, OK). Alternatively, a shallow concavity was prepared in the cut root face by using round diamond burs, with subsequent placement of dentin-bonded resin composite (Retroplast; Retroplast Trading, Rorvig, Denmark). Allocation to MTA or Retroplast treatment groups was not randomized. The distribution of the cases per treatment method during the study period is shown in Fig. 1. After the wound area had been cleaned, primary wound closure was accomplished with multiple interrupted sutures. All surgeries were carried out by the same surgeon (T.v.A.).

Figure 2. (a) A 62-year-old woman was referred for apical surgery. She presented with a radiographic lesion and a separated root canal instrument at her maxillary left central incisor. (b) Postsurgical radiograph shows the MTA retrofilling reaching the existing screw. (c) The 1-year radiograph demonstrates complete healing of the previous radiolucency, with formation of a periodontal ligament space at the cut root-end. Clinically, no signs or symptoms were present. The case was classified as healed.

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Figure 3. (a) A 63-year-old woman was referred for apical surgery of her lower left first molar. The patient denied conventional root canal retreatment. Radiograph shows an apical lesion encompassing both roots of the first molar. (b) Postsurgical radiograph demonstrates that both roots had been resected by about 3 mm, and MTA retrofillings had been placed in both roots. (c) 1-year radiograph exhibits complete periapical resolution of the former periapical radiolucency, and in the absence of clinical signs and symptoms, the case was classified as healed.

Medication All patients were given nonsteroidal analgesics, and patients were instructed to rinse their mouth twice daily with 0.1% chlorhexidine digluconate for 10 days. Antibiotics were not prescribed routinely. Main indications for antibiotic prophylaxis included medically compromised

patients (diabetes, risk of endocarditis, immunosuppression, etc), a history of acute infection, or the presence of clinical signs and symptoms at the preoperative examination. When antibiotics were given, they included 2 g amoxicillin-clavulanic acid or, alternatively, 600 mg clindamycin to be taken 2 hours preoperatively as a 1-shot dose.

Figure 4. (a) A 46-year-old man was referred for apical surgery of his lower left first molar. The mesial root radiographically presented with a fractured root canal instrument that protruded from the apex and a periapical lesion. The distal root had no lesion. (b) Postsurgical radiograph shows the status after root-end resection, removal of the separated instrument, and placement of an adhesive Retroplast filling. (c) 1-year radiograph demonstrates complete resolution of the former radiolucency at the mesial root, and in the absence of clinical signs and symptoms, the case was classified as healed.

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Figure 5. (a) A 35-year-old woman was referred for apical surgery of her maxillary right lateral incisor. Radiograph of this tooth shows a relatively long post and an apical lesion. (b) Postsurgical radiograph exhibits that about 2 mm of the apex had been cut, and an adhesive Retroplast filling had been placed for root-end filling. (c) 1-year radiograph shows a smaller (compared with postsurgical radiograph) but persisting radiolucency indicative of uncertain radiographic healing. The patient had no clinical signs or symptoms. The case was classified as not healed.

Follow-up Patients were seen 4–7 days after surgery for suture removal. All patients were recalled 1 year after periapical surgery for the follow-up examination. Outcome Assessment Healing at the 1-year follow-up was judged clinically and radiographically. The radiographs were taken with a paralleling technique and were evaluated independently by the 3 authors. One-year followup radiographs were compared with postoperative radiographs to define radiographic periapical healing as complete, incomplete (scar tissue formation), uncertain (some reduction of former radiolucency), or unsatisfactory (no reduction or enlargement of former radiolucency), according to the criteria established by Rud et al (16) and Molven et al (17). A specific healing category was selected when 2 examiners agreed on the same healing category. The final healing classification included the radiographic assessment as well as the absence or presence of clinical signs and symptoms of persistent or recurrent periapical pathosis (18). For statistical reasons, the results were dichotomized into healed or not healed cases (19). In healed cases, the radiograph demonstrated complete healing of the former radiolucency or incomplete healing, and no clinical signs or symptoms were present (Figs. 2, 3, 4). In not healed cases, the radiographic healing was assessed as uncertain or unsatisfactory, or clinical signs or symptoms were present, irrespective of the radiographic healing (Fig. 5). The tooth was used as the unit of assessment. For example, if a multirooted tooth presented with 1 healed root and 1 or 2 not healed root(s), the case was classified as not healed. Statistics To assess the inter-rater agreement, kappa values were computed according to the procedure of Fleiss (20, 21). In addition, the concordance between each examiner and the consensus was calculated. The Fisher exact test was performed wherever one had to test the independence of 2 rows and columns in a contingency table with fixed marginals. The only P value computed in a different manner was the one for the null hypothesis of different mean ages in the 2 treatment groups, where a t test was performed. Statistical tests JOE — Volume 36, Number 7, July 2010

were carried out for MTA and Retroplast separately. Because several primary end points have not been assessed, the P values were not corrected for multiple testing. All analyses were performed with the statistical program R (R 2.9.0; The R Foundation for Statistical Computing, Vienna, Austria).

Results The initial material comprised 353 teeth in the same number of patients. Fourteen teeth were lost for follow-up (dropout rate, 4%) (Table 1). The final study sample included 339 teeth in 158 men and 181 women. Patients had a mean age of 50.3 years (10.8 years; range, 11–83 years). The details of gender, age, treated teeth, and type of surgery per treatment group are presented in Table 2. The retrofilling material was MTA in 51% and Retroplast in 49% of the assessed cases. Gender and age distribution, as well as mean age and range of age, were similar for both treatment groups (P = 1.00 for gender, P = .20 for age, and P = .82 for mean age). With regard to treated teeth, the Retroplast group comprised more mandibular molars (30.1%) than the MTA group (22.5%) (P = .14). In contrast, the MTA group included more anterior teeth (32.9%) than the Retroplast group (24.7%) (P = .12). The detailed analysis of the presence of a post/screw per type of treated tooth showed no significant differences when comparing MTA and Retroplast cases (P = .19 to P = 1.0) (Table 3). Cases with first-time surgery or TABLE 1. Included Material and Dropouts (n = 353) Initially included material Dropouts Tooth extracted, not related to apical surgery Patient failed to attend for followup No follow-up radiograph taken Final material

MTA

Retroplast

Total

178

175

353

5 (2.8%) 3

9 (5.1%) 3

14 (4.0%) 6

2

4

6

0

2

2

173

166

339

MTA, mineral trioxide aggregate.

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Gender Male Female Age <45 y $45 y Mean years () Range of years Maxilla Anterior teeth* Premolars Molars Mandible Anterior teeth* Premolars Molars Surgery First-time Re-surgery

Retroplast (n = 166) (49%)

Total (n = 339) (100%)

n

%

n

%

n

%

81 92

46.8 53.2

77 89

46.4 53.6

158 181

46.6 53.4

63 110 49.8 (11.7) 11–83

36.4 63.6 N/A N/A

49 117 50.9 (9.9) 14–81

29.5 70.5 N/A N/A

112 227 50.3 (10.8) 11–83

33.0 67.0 N/A N/A

57 30 31

32.9 17.3 17.9

41 37 26

24.7 22.3 15.7

98 67 57

28.9 19.8 16.8

5 11 39

2.9 6.4 22.5

3 9 50

1.8 5.4 30.1

8 20 89

2.4 5.9 26.3

153 20

88.4 11.6

149 17

89.8 10.2

302 37

89.1 10.9

MTA, mineral trioxide aggregate; N/A, not applicable; y, years. *Anterior teeth = incisors and canines.

re-surgery were also similarly distributed among the 2 treatment groups. For the MTA group, kappa values for interexaminer agreement ranged from 0.49–0.64, and agreement was rated as moderate to substantial; concordance for the MTA group between each examiner and the consensus ranged from 0.63–0.85, and agreement was rated as substantial to almost perfect. For the Retroplast group, kappa values for interexaminer agreement ranged from 0.48–0.51, and agreement was rated as moderate; concordance for the Retroplast group between each examiner and the consensus ranged from 0.68–0.72, and agreement was rated as substantial. The overall rate of healed cases was 85.5%, with a significantly higher rate of 91.3% for MTA compared with 79.5% for Retroplast (P = .003). The categorization of healing according to clinical and radiographic parameters is shown in Table 4. With regard to the radiographic healing classification, MTA (85.5%) showed more (P = .03) completely healed cases than Retroplast (77.1%), whereas significantly (P = .003) more uncertain cases were observed for Retroplast (16.3%) compared with MTA (5.8%). Percentages of incomplete and unsatisfactory cases were similar in both treatment groups. With regard to the different types of treated teeth, a considerable variation in rates of healed cases was found for Retroplast-treated teeth (Table 5); for instance, mandibular premolars (66.7%) and mandibular molars (68%) had lower rates of healed cases than maxillary anterior teeth (90.2%). In contrast, MTA presented with similar rates of healed cases, irrespective of the treated teeth. No significant differences between MTA and Retroplast were observed for rates of healed cases per type of treated tooth and presence or absence of a post/screw (Tables 6 and 7). Rates of healed cases in resurgeries were lower than in first-time surgeries for all teeth, but also within the 2 treatment groups; however, the differences were not statistically significant (overall, P = .46; MTA, P = .39; Retroplast, P = .75) (Table 4).

Discussion The present clinical study assessed the healing outcome 1 year after apical surgery with 2 different methods of root-end preparation 1126

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and filling. Because the MTA and Retroplast techniques use 2 different methods of root-end preparation, differences in treatment outcome cannot solely be attributed to the filling material itself. Therefore, the data of the present study reflect differences of root-end management techniques rather than differences of root-end filling materials. Although the overall rate of healed cases was 85.5%, a significantly higher rate of 91.3% was found for cases treated with MTA compared with 79.5% for Retroplast cases. Interestingly, the proportion of cases classified radiographically as unsatisfactory was identical for the 2 treatment modalities, whereas a significantly higher proportion of cases with uncertain healing were observed with Retroplast than with MTA. Previous short-term and long-term studies on apical surgery with Retroplast as retrofilling material have reported similar outcomes after 1 year as in the present study (22, 23). However, a clinical study on Retroplast with a follow-up of at least 5 years showed that 60% of the uncertain cases at 1 year could be classified as healed after 5 years (23). This is in accordance with other long-term studies of Retroplast (24–26). Because polymerized Retroplast has been documented to be TABLE 3. Distribution of Cases with a Post/screw per Type of Treated Tooth and Treatment Method MTA (n = 173)

Maxilla Anterior teeth* Premolars Molars Mandible Anterior teeth* Premolars Molars

Retroplast (n = 166)

n

%

n

%

P value

37/57 19/30 5/31

64.9 63.3 16.1

31/41 24/37 3/26

75.6 64.9 11.5

.28 1.00 .72

1/5 9/11 12/39

20.0 81.8 30.8

2/3 7/9 23/50

66.7 77.8 46.0

.46 1.00 .19

MTA, mineral trioxide aggregate. In multirooted teeth, the root(s) undergoing apical surgery had to have a post/screw to be classified ‘‘with a post/screw’’ (for example, a maxillary molar with a post in the palatal root, but with apical surgery performed on both buccal roots having no post/screw, was classified as having no post/ screw). *Anterior teeth = incisors and canines.

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Clinical Research TABLE 4. Summary of Clinical and Radiographic Healing Assessment per Treatment Method (n = 339)

Healing

Success

Clinical signs/ symptoms

Healed Healed Not healed Not healed Not healed Not healed Not healed Not healed

Successful Successful Doubtful Failure Failure Failure Failure Failure

No No No No Yes Yes Yes Yes

Radiographic healing Complete Incomplete Uncertain Unsatisfactory Complete Incomplete Uncertain Unsatisfactory

MTA (n = 173)

Retroplast (n = 166)

Total (n = 339)

n

%

n

%

n

%

148 10 10 1 0 0 0 4

85.5 5.8 5.8 0.6 — — — 2.3%

126 6 25 1 2 0 2 4

75.9 3.6 15.1 0.6 1.2 — 1.2 2.4

274 16 35 2 2 — 2 8

80.8 4.7 10.3 0.6 0.6 — 0.6 2.4

MTA, mineral trioxide aggregate.

highly biocompatible (27), it can be speculated that the slower ‘‘radiographic’’ healing when comparing Retroplast with MTA might be caused by the glutaraldehyde-containing dentin-bonding agent, a potentially toxic substance to bone. Recently published clinical studies have consistently reported higher success rates for MTA compared with other root-end filling materials, but no statistically significant differences have been found in these studies (Table 8). The present study is the first to demonstrate a significantly higher rate of healed cases when comparing MTA with another root-end filling material. The strength of the present study is the number of treated cases per group (MTA, n = 173; Retroplast, n = 166). The number of MTA cases in previous comparative studies ranged between 50 and 61 (Table 8). The weakness of the present study is that no randomization with regard to the root-end filling technique was performed. As Fig. 1 demonstrates, the MTA technique was exclusively used at the beginning and at the end of the study period, whereas the Retroplast technique was mainly used in the middle third of the study period. Analysis of the clinical studies on MTA used as a retrofilling material in apical surgery raises 2 interesting points: the high percentage of successful outcomes (above 90%) and the consistency of reported success rates (Table 8). The clinical results appear to confirm the data of experimental studies on MTA that have described enhanced physical, chemical, and biologic characteristics of this material compared with other root-end filling materials (28). A detailed analysis of clinical comparative studies on Retroplast shows a range of successful healing between 73% and 80% (Table 9). Only 1 randomized controlled trial has compared Retroplast with

another retrofilling material, ie, glass ionomer cement (GIC) (22). Whereas GIC yielded a very low healing rate of 31%, Retroplast was classified as successful in 73% of treated teeth. Published success rates of Retroplast when compared with other root-end filling techniques in clinical studies have always been lower than those of MTA (Tables 8 and 9). Because Retroplast uses an adhesive technique, various problems encountered during surgery might result in compromised healing. Difficulties include inadequate control of hemorrhage, limited dentin area at the cut root face (large pulp canals, ‘‘false canal,’’ thin radicular dentin after arrest of root formation after dental trauma), ‘‘empty’’ pulp canal at resection level, or Retroplast in direct contact with a radicular post or screw. With regard to the root canal content, Rud et al (25) reported a significantly (P = .004) lower healing rate by using Retroplast for root-end sealing in teeth with empty canals (81%) compared with teeth with root filling to the apex (92%) (follow-up period of 2–4 years). Another contributing factor to lower success rates of Retroplast might be that surgical microscopes or endoscopes had not been used in the previously published studies on Retroplast. With regard to the type of treated teeth, the present study also found some differences when comparing MTA and Retroplast. Among MTA-treated teeth, the rates of healed cases ranged from 89.5%– 100% across the various tooth groups, whereas a wider range of rates was observed for Retroplast, ie, 66.7%–100%. It is noteworthy that in Retroplast-treated teeth, mandibular premolars and molars only had rates of healed cases of 66.7% and 68%, respectively. These relatively low rates might be explained by the more difficult access in the posterior mandible and a high occurrence of an isthmus, in particular in the

TABLE 5. Healed Cases per Type Of Tooth and Type Of Surgery in Relation to Treatment Method (n = 339) MTA (n = 173) n healed/n group All Maxilla Anterior teeth* Premolars Molars Mandible Anterior teeth* Premolars Molars Surgery First-time Re-surgery

Retroplast (n = 166) %

Total (n = 339)

n healed/n group

%

n healed/n group

%

158/173

91.3

132/166

79.5

290/339

85.5

51/57 29/30 28/31

89.5 96.7 90.3

37/41 29/37 23/26

90.2 78.4 88.5

88/98 58/67 51/57

89.8 86.6 89.5

5/5 10/11 35/39

100 90.9 89.7

3/3 6/9 34/50

100.0 66.7 68.0

8/8 16/20 69/89

100 80.0 77.5

141/153 17/20

92.2 85.5

119/149 13/17

260/302 30/37

86.1 81.1

79.9 76.5

MTA, mineral trioxide aggregate. *Anterior teeth = incisors and canines.

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Clinical Research TABLE 6. Distribution of Healed Cases with a Post/screw per Type of Treated Tooth and Treatment Method MTA (n = 83)

Maxilla Anterior teeth* Premolars Molars Mandible Anterior teeth* Premolars Molars

TABLE 7. Distribution of Healed Cases without a Post/screw per Type of Treated Tooth and Treatment Method

Retroplast (n = 90)

MTA (n = 90)

n

%

n

%

P value

33/37 19/19 5/5

89.2 100 100

28/31 20/24 3/3

90.3 83.3 100

1.00 .12 1.00

1/1 8/9 10/12

100 88.9 83.3

2/2 6/7 14/23

100 85.7 60.9

1.00 1.00 .26

Maxilla Anterior teeth* Premolars Molars Mandible Anterior teeth* Premolars Molars

Retroplast (n = 76)

n

%

n

%

P value

18/20 10/11 23/26

90.0 90.9 88.5

9/10 9/13 20/23

90.0 69.2 87.0

1.00 .33 1.00

4/4 2/2 25/27

100 100 92.6

1/1 0/2 20/27

100 0 74.1

1.00 .33 .14

MTA, mineral trioxide aggregate. *Anterior teeth = incisors and canines.

MTA, mineral trioxide aggregate. *Anterior teeth = incisors and canines.

mesial roots of mandibular molars (29). Another reason might be the different technique of root-end cavity preparation. Whereas in MTAtreated teeth a 3-mm-deep cavity was prepared, the Retroplast technique only included the preparation of a shallow concavity of about 1-mm depth at the cut root face. This involves the risk of missing lingually positioned canals or ramifications, in particular when beveling root ends in mandibular premolars and molars. Furthermore, nonnegotiated ‘‘empty’’ pulp canal structures, such as isthmuses or accessory canals, might be critical (leakage, inadequate dryness, hollow cavity) for an adhesive technique of root-end filling at the cut root face. This assumption is supported by the work on Retroplast by Rud et al (25), in which mandibular first molars with root filling to the apex had a success rate of 88%, compared with a success rate of only 71% for mandibular first molars with empty canals. First-time surgeries had a higher rate of healed cases than resurgeries in the overall study population (86.1% versus 81.1%, respectively) as well as for the MTA cases (92.2% versus 85.5%, respectively) and Retroplast cases (79.9% versus 76.5%, respectively). However, these differences were not statistically significant. In the literature, it

is well-documented that apical re-surgery has a poorer outcome than first-time apical surgery. However, the reported differences were not always statistically significant (14, 19, 30–32). The reasons for lower healing rates in re-surgery cases have never been fully understood or clarified. The quality of postsurgical healing might depend on factors other than the resective procedure or the sealing at the cut root face, such as tissue response, healing capacity, or oral and systemic health (33).

Conclusions Within the limits of this prospective, nonrandomized clinical study comparing the 1-year outcome of apical surgery by using 2 different methods of root-end preparation and filling, the following conclusions can be drawn: - MTA-treated teeth demonstrated a significantly higher rate of healed cases 1 year after apical surgery than Retroplast-treated teeth. - For MTA-treated teeth, the relatively high rate of healed cases of 91.3% is in line with previously published data.

TABLE 8. Summary of Clinical Studies Comparing MTA with Other Root-end Filling Materials in Apical Surgery Follow-up period

Successful healing

Chong et al/2003

Authors/year

Randomized controlled trial

Study design

n = 108 (MTA, n = 61; IRM, n = 47)

Final material

2y

MTA, 92%; IRM, 87% (P > .05)

Lindeboom et al/ 2005 Kim et al/2008

Randomized controlled trial Retrospective clinical study

n = 100 (MTA, n = 50; IRM, n = 50) n = 188 (MTA, n = 47; IRM, n = 9; SuperEBA, n = 132)

1y

MTA, 92%; IRM, 86% (P > .05) MTA, 92%; IRM, 89%; SuperEBA, 92% (P > .05)

Present study

Prospective clinical study

n = 339 (MTA, n = 173; Retroplast, n = 166)

1y

>1 y up to 5 y

Remarks No mandibular molars were treated. Cases with complete healing after 1 y that failed to present at the 2-y follow-up were included as healed in final analysis. No molars were treated. Study material included 40 cases with varying degrees of endodonticperiodontal lesions.

MTA, 91%; Retroplast, 80% (P = .003)

IRM, intermediate restorative material; MTA, mineral trioxide aggregate; y, years.

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Clinical Research TABLE 9. Summary of Clinical Studies Comparing Retroplast with Other Root-end Filling Materials in Apical Surgery Follow-up period

Successful healing

Rud et al/1991

Authors/year

Retrospective clinical study

Study design

n = 776 (Retroplast, n = 388; amalgam, n = 388)

Final material

6 mo–1 y

Retroplast, 78%; amalgam, 62% (P < .00005)

Jensen et al/2002

Randomized controlled trial

1y

Present study

Prospective clinical study

n = 122 (Retroplast, n = 60; GIC, n = 62) n = 339 (Retroplast, n = 166; MTA, n = 173)

Retroplast, 73%; GIC, 31% (P < .001) Retroplast, 80%; MTA, 91% (P = .003)

1y

Remarks The amalgam cases were randomly selected among patients previously treated (historical control group).

GIC, glass ionomer cement; mo, months; MTA, mineral trioxide aggregate; y, years.

- Irrespective of the treated type of tooth, MTA cases were associated with consistent and high rates of healed cases, whereas rates of healed cases of Retroplast-treated mandibular premolars and molars were relatively low. - The observed differences in treatment outcome might not be solely associated with the filling material (MTA versus Retroplast) because 2 different root-end preparation methods were used without controls; a box-shaped cavity was prepared with sonic-driven microtips for MTA, and a shallow concavity was prepared with round diamond burs for Retroplast.

14. 15.

16. 17.

Acknowledgments

18.

The statistical evaluation by Mr Gabriel Fischer, Institute of Mathematical Statistics and Actuarial Science, University of Bern, Switzerland, is gratefully acknowledged.

19. 20. 21.

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