Five-Year Longitudinal Assessment of the Prognosis of Apical Microsurgery

1. Clinical Research
Five-Year Longitudinal Assessment of the Prognosis
of Apical Microsurgery
Thomas von Arx, DMD,* Simon S. Jensen, DDS,*† Stefan H€ nni, DMD,‡
a
and Shimon Friedman, DMD§
Abstract
Introduction: Apical surgery is an important treatment Key Words
option for teeth with post-treatment apical periodon- Apical surgery, long-term study, outcome, predictors, prognostic factors
titis. Knowledge of the long-term prognosis is necessary
when weighing apical surgery against alternative treat-
ments. This study assessed the 5-year outcome of apical
surgery and its predictors in a cohort for which the
A pical surgery is an important endodontic treatment modality intended to cure
persistent apical periodontitis (AP) after orthograde root canal treatment.
Post-treatment AP has been shown to affect up to 65% of root-filled teeth in different
1-year outcome was previously reported. Methods: populations (1). This highly prevalent condition is preferably treated by orthograde
Apical microsurgery procedures were uniformly per- (nonsurgical) retreatment; however, specific benefit-risk analysis or patient
formed using SuperEBA (Staident International, Staines, preference may favor apical surgery as the treatment of choice (2). As an alternative
UK) or mineral trioxide aggregate (MTA) (ProRoot MTA; to nonsurgical or surgical retreatment, the tooth can be extracted and replaced with
Dentsply Tulsa Dental Specialties, Tulsa, OK) root-end an implant-supported restoration, with a tooth-borne fixed prosthesis, or with a
fillings or alternatively Retroplast capping (Retroplast removable prosthesis (3). Thus, for teeth with post-treatment AP, patients currently
Trading, Rorvig, Denmark). Subjects examined at can select from 3 contrasting treatment options. A critical consideration in this
1 year (n = 191) were invited for the 5-year clinical challenging decision juncture is the prognosis, as suggested by the current best
and radiographic examination. Based on blinded, in- evidence for each treatment option. This study addressed the outcome of apical
dependent assessment by 3 calibrated examiners, the surgery.
dichotomous outcome (healed or nonhealed) was deter- Over the years, over 75 studies have reported a very wide range of data on the
mined and associated with patient-, tooth-, and prognosis of apical surgery using a variety of root-end filling materials and surgical
treatment-related variables using logistic regression. techniques (4). Attempts to narrow the range of the reported outcomes by selecting
Results: At the 5-year follow-up, 9 of 191 teeth were studies based on methodological rigor and to identify significant outcome predictors
unavailable, 12 of 191 teeth were extracted, and 170 have been reported (4, 5). In a recent systematic review and meta-analysis, Setzer
of 191 teeth were examined (87.6% recall rate). A total et al (6) concluded that the prognosis of ‘‘endodontic microsurgery’’ including the
of 129 of 170 teeth were healed (75.9%) compared with use of high-power illumination and magnification (microscope or endoscope);
83.8% at 1 year, and 85.3% were asymptomatic. Two ultrasonic tips for root-end cavity preparation; and mineral trioxide aggregate
significant outcome predictors were identified: the (MTA), intermediate restorative material, or SuperEBA for root-end filling is signif-
mesial-distal bone level at #3 mm versus >3 mm icantly better than that of the ‘‘traditional root-end surgery’’ performed in many of
from the cementoenamel junction (78.2% vs 52.9% the studies. The reviewers suggest a 94% chance to cure post-treatment AP after
healed, respectively; odds ratio = 5.10; confidence endodontic microsurgery (6); however, this conclusion is supported exclusively
interval, 1.67-16.21; P < .02) and root-end fillings by short-term (1 or 2 years) outcome reports. Considering the 5% to 25% risk
with ProRoot MTA versus SuperEBA (86.4% vs. 67.3% of regression to AP reported beyond 3 or more years after apical surgery
healed, respectively; odds ratio = 7.65; confidence (7–12), the short-term data supporting the current systematic review’s conclusions
interval, 2.60-25.27; P < .004). Conclusions: This study (6) may overestimate the long-term prognosis of endodontic microsurgery (4).
suggested that the 5-year prognosis after apical micro- Similarly, the assessment of significant outcome predictors requires long-term
surgery was 8% poorer than assessed at 1 year. It observations as reported in only 4 studies (12–15), none of which focused on
also suggested that the prognosis was significantly endodontic microsurgery. By reviewing the contrasting results of these 4 studies
impacted by the interproximal bone levels at the and the recent reviews, the potential significant predictors of healing after apical
treated tooth and by the type of root-end filling material surgery may be patient related (patient’s age over 45 years), tooth related (the
used. (J Endod 2012;38:570–579) absence of preoperative signs and symptoms, adequate root filling density,
From the *Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland; †Department of Oral and Maxillofacial
Surgery, Copenhagen University Hospital, Copenhagen, Denmark; ‡Private Practice, Bern, Switzerland; and §Discipline of Endodontics, Faculty of Dentistry, University of
Toronto, Toronto, Ontario, Canada.
Address requests for reprints to Dr Thomas von Arx, Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Freiburgstrasse 7,
CH-3010 Bern, Switzerland. E-mail address: thomas.vonarx@zmk.unibe.ch
0099-2399/$ - see front matter
Copyright ª 2012 American Association of Endodontists.
doi:10.1016/j.joen.2012.02.002
570 von Arx et al. JOE — Volume 38, Number 5, May 2012

2. Clinical Research
inadequate root filling length, a small periapical lesion of #5 mm, The entire cohort of 191 subjects attending the 1-year examination
and the absence of a post), and treatment related (use of the was accounted for at the 5-year juncture. Teeth that had been extracted
microsurgical technique) (5, 12–15). were recorded along with the diagnosis at the time of extraction. All
To further elucidate the prognosis of apical microsurgery and the subjects who did not respond, declined examination, or could not be
outcome predictors, the purpose of this prospective longitudinal study reached were considered lost to follow-up.
was to provide evidence for the 5-year outcome of apical microsurgery The treatment provider performed all follow-up examinations. To
in a cohort of patients for whom we previously reported the 1-year minimize bias, the examination and data entry were performed blinded
outcome (16). Furthermore, patient-, tooth-, and treatment-related of the subject’s pre- and postoperative data. Subjects were asked
variables were investigated for their outcome-predicting value to to report occurrences of pain. The clinical examination recorded the
provide clinicians with the ability to project the particular prognosis presence or absence of swelling and sinus tract and the response to
for specific patients who consider apical microsurgery versus alterna- percussion and palpation. Radiographs were exposed using the
tive options. paralleling technique with the use of the XCP Rinn film holder (Dentsply
Rinn, Elgin, IL) to assess the periapical status.
Materials and Methods
The study cohort and interventions were characterized previously Outcome Assessment
(16); however, key characteristics and details not provided previously Outcome was assessed based on clinical and radiographic
are described herein to satisfy the requirement of adequate reporting. measures. Radiographs were interpreted independently by 2
examiners (S.H. and S.S.J.) and by the treatment provider who were
Study Cohort all previously calibrated for use of the healing classification described
Subjects were recruited from among 251 patients who received by Molven et al (17). Calibration included the radiographic assessment
apical surgery at the Department of Oral Surgery and Stomatology, of sample cases using the schematic depiction of the healing categories
School of Dental Medicine, University of Bern, Bern, Switzerland, (17). Intra- and interexaminer agreement was assessed using the Cohen
from January 2000 to December 2003. A total of 194 teeth in the kappa statistics.
same number of subjects met the inclusion criteria (16) and were The radiographic evidence of periapical healing was classified
enrolled in the study. This cohort is characterized for key patient- as complete (Fig. 1), incomplete (scar tissue formation, Fig. 2),
and tooth-related preoperative variables in Table 1. uncertain (Fig. 3), or unsatisfactory (Fig. 4) in strict adherence to
well-established universal criteria (17, 18). Interpretation conflicts
Intervention were resolved by reaching consensus among the 3 examiners. To
One oral surgeon (T.v.A.) who has extensive experience in per- ascertain that all allocations to the ‘‘incomplete healing’’ category
forming apical microsurgery provided all treatments. The surgical were appropriate, the teeth in this category underwent additional
technique was previously described in detail (16). Briefly, local anes- independent scrutiny by a fourth examiner (S.F.).
thesia was administered; full-thickness mucoperiosteal flap elevated; With the tooth considered as the evaluated unit and mul-
osteotomy performed; the apical 3 mm of the root resected with no tirooted teeth classified according to the worst-appearing root, the
or minimal bevel; the pathological tissue curetted; hemostasis estab- outcome was defined by combining the clinical and radiographic
lished; and the root end inspected with a rigid endoscope for accessory measures (19). Teeth were classified as ‘‘healed’’ when presenting
canals, isthmus, and cracks. Two methods of root-end management with complete or incomplete healing without clinical signs and
were used without randomized allocation: (1) a root-end cavity was symptoms. Teeth were classified as ‘‘not healed’’ when presenting
prepared with sonic microtips (Kavo Dental, Biberach, Germany) with uncertain or unsatisfactory healing or with clinical signs or symp-
and filled with either SuperEBA (Staident International, Staines, UK) toms regardless of the radiographic appearance. In addition to the
in 55 subjects (28.4%) or with ProRoot MTA (Dentsply Tulsa Dental healing outcome, teeth were classified as ‘‘functional’’ based on the
Specialities, Tulsa, OK) in 53 subjects (27.3%) and (2) a shallow absence of clinical signs and symptoms regardless of the radiographic
concavity was drilled into the root end and sealed with a resin appearance.
composite (Retroplast; Retroplast Trading, Rorvig, Denmark) bonded
with Gluma (Heraeus Kulzer, Dormagen, Germany) in the remaining 86 Statistical Analysis
subjects (44.3%). Flaps were secured with interrupted sutures (Sera- Percent frequencies were generated to characterize the study
lon; Serrag-Wiessner, Nalla, Germany). Nonsteroidal analgesics and material in regards to 14 independent variables: patient related
a 0.12% chlorhexidine-digluconate mouthwash were prescribed (ie, age, sex, and smoking), tooth related (ie, tooth type, pain, clinical
routinely, whereas prophylactic antibiotics were prescribed for 61% signs/symptoms [tenderness to palpation or percussion, swelling, and
of subjects. The main indications for antimicrobial prophylaxis sinus tract], size of periapical lesion, interproximal bone level, apical
included a history of acute infection, the presence of clinical signs extent of root canal filling, post, and previous apical surgery), and treat-
and symptoms at the preoperative examination, and an anticipated ment related (ie, antibiotic prescription, root-end filling material, and
duration of surgery longer than 1 hour. initial postoperative healing).
Interexaminer agreement was assessed with the Cohen weighted
Follow-up Examination kappa statistics. All statistical analyses were performed with the software
At the 1-year follow-up examination, subjects were advised that R version 2.12.2 (The R Foundation for Statistical Computing, Vienna,
they would be contacted 4 years later for an additional clinical Austria). The dependent variable, the dichotomous outcome (healed vs
and radiographic examination of the surgically treated teeth. With nonhealed), was assessed for associations with all 14 measured in-
3 subjects lost to follow-up at the 1-year examination (16), a total of dependent variables using multivariate analysis. Logistic regression
191 subjects were invited by letter to attend the 5-year examination. models were constructed to identify significant outcome predictors
Those subjects who did not respond were contacted by telephone while accounting for confounding associations and extraneous vari-
and encouraged to attend without an offer of reimbursement. ables. Significance was established at the 5% level. Because of the
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3. Clinical Research
TABLE 1. Preoperative Characteristics of the Inception Cohort (n = 194) and the Healed Outcome at 1 Year (n = 191) and 5 Years (n = 170) after Apical
Microsurgery Related to Potential Outcome Predictors
Inception
cohort 1-year follow-up 5-year follow-up
Variable n %n n Healed % healed n Healed % healed
Total 194 100 191 160 83.8 170 129 75.9
Age
<45 years 60 30.9 60 54 90.0 56 44 78.6
$45 years 134 69.1 131 106 80.9 114 85 74.6
Sex
Male 86 44.3 85 68 80.0 76 54 71.1
Female 108 55.7 106 92 86.8 94 75 79.8
Smoking
No 141 72.7 139 116 83.5 123 97 78.9
Yes 53 27.3 52 44 84.6 47 32 68.1
Teeth
Maxilla anteriors 55 28.4 54 46 85.2 52 43 82.7
Premolars 43 22.2 42 35 83.3 34 27 79.4
Molars 25 12.9 24 22 91.7 23 16 69.6
Mandible anteriors 6 3.1 6 6 100 2 1 50.0
Premolars 13 6.7 13 10 76.9 12 10 83.3
Molars 52 26.8 52 41 78.8 47 32 68.1
Pain
Absent 111 57.2 109 97 89.0 98 76 77.6
Present 83 42.8 82 63 76.8 72 53 73.6
Signs
Absent 116 59.8 114 101 88.6 103 77 74.8
Tender to percussion 30 15.5 30 25 83.3 23 19 82.6
Swelling, sinus tract 48 24.7 47 34 72.3 44 33 75.0
Lesion size
No lesion 17 8.8 17 16 94.1 16 14 87.5
#5 mm 106 54.6 104 90 86.5 91 74 81.3
>5 mm 71 36.6 70 54 77.1 63 41 65.1
Crestal bone level*
Mesial and distal #3 mm 150 77.3 148 123 83.1 133 104 78.2
Mesial or distal >3 mm 24 12.4 24 21 87.5 20 16 80.0
Mesial and distal >3 mm 20 10.3 19 16 84.2 17 9 52.9
Apical extent of root canal filling
0-2 mm short of apex 126 64.9 123 103 83.7 108 84 77.8
>2 mm short of apex 44 22.7 44 39 88.6 41 30 73.2
Beyond the apex 24 12.4 24 18 75.0 21 15 71.4
Post
Absent 64 33.0 63 53 84.1 53 41 77.4
Present 130 67.0 128 107 83.6 117 88 75.2
Previous surgery
No 176 90.7 173 146 84.4 154 118 76.6
Yes 18 9.3 18 14 77.8 16 11 68.8
Antibiotics
Not prescribed 72 64 88.9 62 51 82.3
Prescribed 119 96 80.7 108 78 72.2
Root-end filling
SuperEBA 55 42 76.4 49 33 67.3
ProRoot MTA 51 46 90.2 44 38 86.4
Retroplast 85 72 84.7 77 58 75.3
Postoperative healing
Uneventful 174 148 85.1 156 120 76.9
Complication 17 12 70.6 14 9 64.3
*Measured on radiographs from the cementoenamel junction or, if not visible, from the margin of a crown or filling.
exploratory type of the study, no P value correction for multiple unrelated to the surgical treatment performed. Three subjects (1.5%)
comparisons was performed. could not be reached, 6 subjects (3.1%) did not respond, and 3
subjects (1.5%) did not attend the 1-year examination. The total loss
Results to follow-up from baseline to 5 years was 24 subjects (12.4%) including
Attrition of the cohort at the 5-year follow-up examination is the extracted teeth.
summarized in Table 2. A total of 170 of 194 subjects (87.6%) with
the same number of treated teeth were available for re-examination after Interexaminer Agreement
5 years. Information was available for an additional 12 teeth (6.2%) that Kappa values of pair-wise comparisons among the 3
were extracted because of fracture or prosthetic considerations examiners with regard to radiographic healing classification ranged
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4. Clinical Research
Figure 1. Mandibular first molar radiographically assessed as ‘‘complete healing’’ 5 years after apical microsurgery with ProRoot MTA root-end filling. (A) Preop-
erative and (B) postoperative: in the mesial root, both canals and the isthmus were prepared and filled, whereas in the distal root 1 canal was prepared and filled.
(C) The 1-year follow-up and (D) the 5-year follow-up.
from 0.59 to 0.74, indicating fair to good agreement. A good to excellent uncertain/unsatisfactory healing was lowest in teeth treated with
agreement was observed between each examiner’s classification ProRoot MTA.
and the consensus classification, with kappa values ranging from
0.74 to 0.92. Outcome Predictors
The following variables were associated with healed rate dif-
Outcome ferences of 10% or larger (considered clinically meaningful) at 5 years:
Five years after apical microsurgery, 129 of 170 teeth (75.9%)
1. Patient related: smoking status
were classified as healed compared with 83.8% at 1 year after treatment.
2. Tooth related: the type of tooth, the size of the lesion, and the crestal
Taking into account the absence of clinical signs or symptoms, 145 of
bone level
170 teeth (85.3%) were classified as ‘‘functional’’ 5 years after apical 3. Treatment related: the type of root-end filling material, antibiotic
surgery. Distribution of the radiographic classification categories for
treatment, and the postoperative healing course
the 170 teeth examined at 5 years is summarized in Table 3. Of 141 teeth
classified as complete/incomplete healing at 1 year, 125 teeth (88.7%) The final logistic regression model revealed 1 tooth-related and 1
remained so at 5 years, whereas 16 teeth (11.3%) regressed to uncer- treatment-related statistically significant predictor of a healed outcome:
tain /unsatisfactory healing at 5 years. Conversely, of 29 teeth classified mesial-distal crestal bone level at #3 mm versus >3 mm from the
as uncertain/unsatisfactory healing at 1 year, 5 teeth (17.2%) pro- cementoenamel junction (78.2% vs 52.9% healed, respectively; odds
gressed to complete/incomplete healing. On balance, the number of ratio = 5.10; confidence interval, 1.67–16.21; P < .02) and root-end
teeth classified as complete/incomplete healing decreased from 141 fillings with ProRoot MTA versus SuperEBA (86.4% vs 67.3% healed,
teeth at 1 year to 130 teeth at 5 years after treatment, a reduction respectively; odds ratio = 7.65; confidence interval, 2.60–25.27;
of 7.8%. With regard to root-end filling materials, regression to P < .004; Tables 1 and 4).
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Figure 2. The maxillary lateral incisor radiographically assessed as ‘‘incomplete healing’’ 5 years after apical microsurgery with ProRoot MTA root-end filling.
(A) Preoperative, (B) postoperative, (C) 1-year follow-up, and (D) 5-year follow-up.
Discussion follow-up reported in other relatively current apical surgery studies
This prospective longitudinal study evaluated the 5-year prognosis with comparable observation periods (8, 10–12, 14, 15, 20). The
of apical microsurgery in a cohort for whom the 1-year data have been 88% recall rate achieved was consistent with the requirement for
reported previously (16). The study design was consistent with the the second highest level of evidence (1b) for the assessment of
methodology requirements for the assessment of prognosis at a high prognosis (21). Only 1 tooth per subject was included and considered
level of evidence. The study cohort was recruited, treated, and the unit of evaluation, and teeth presenting with through-and-through or
followed-up prospectively, with data reported for subjects attending apicomarginal lesions were excluded to ascertain uniformity of the
both the 1-year (16) and 5-year examinations. The roughly 12% attri- cohort and to avoid potential confounding of the results. Patient- and
tion of the inception cohort was lower than the 22% to 49% loss to tooth-related data collection followed a detailed protocol; however,
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Figure 3. The mandibular first molar radiographically assessed as ‘‘uncertain healing’’ 5 years after apical microsurgery with Retroplast root-end capping.
(A) Preoperative and (B) postoperative: both resected root faces were sealed including an isthmus in the mesial root. (C) The 1-year follow-up and (D) the
5-year follow-up.
the inception cohort was not characterized in regards to AP persisting Different patient-, tooth-, and treatment-related variables were
after the initial treatment only or after retreatment as would have been explored for association with the outcome, and significant outcome
desired (4). Although the prognosis of apical surgery was better when predictors were identified using a multivariate analysis. Because this
AP persisted after retreatment than after initial treatment in 1 study (22), study followed up the cohort for whom the 1-year data were available,
this variable was not a significant outcome predictor in another no sample size calculation was performed, and no specific sample size
study (15). target was set.
To standardize interventions, 1 provider treated all subjects, and The overall 5-year healed rate of 76% (129/170 subjects)
all teeth were root-end filled following a uniform surgical protocol. compared well with the 4- to 10-year healed rate of 74% reported in
Because the root-end filling techniques were not randomly allocated, the Toronto Study (15). In that study, not all subjects were treated using
the level of evidence for comparing their effectiveness was lower the apical microsurgical technique, and 84% of teeth were root-end
(2b) than would be provided by a randomized controlled trial (21). filled with ProRoot MTA, intermediate restorative material, or SuperEBA
To ascertain objective outcome assessment, 2 independent exam- without a significant difference in outcome (15). In current years, only
iners and the treatment provider interpreted the radiographic images a few apical surgery studies assessed the outcomes of 4 years or longer
blinded to the preoperative appearance. Blinding of root-end filling (10–15, 20, 22, 23), whereas there have been many short-term studies
materials was not entirely possible because of the different radiographic (4). Especially in the past decade, many studies have reported on
appearance of the 3 materials used. Stents were not manufactured to the outcome of apical microsurgery (6), albeit with only short-term
facilitate reproducible radiographic exposures, as was the case in the (#2 years) follow-up. Short-term observation after apical surgery
majority of apical surgery outcome studies; nevertheless, radiographs may overestimate the prognosis (4) because 5% to 25% of teeth re-
were positioned with a film holder, and the paralleling exposure corded as healed at the short-term have been reported to regress
technique was used to reduce distortion. when observed 3 years or longer after surgery (7–12). In the
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Figure 4. The mandibular first molar radiographically assessed as ‘‘unsatisfactory healing’’ 5 years after apical microsurgery with Retroplast root-end capping. (A)
Preoperative and (B) postoperative: the resected root face of the mesial root was sealed including the isthmus. (C) The 1-year follow-up and (D) the 5-year follow-up.
present apical microsurgery study, regression occurred in perspective, the supporting bone level should be assessed preopera-
approximately 11% of teeth assessed as healed at 1 year. This tively and carefully considered before the tooth is subjected to apical
regression was partially offset by fewer teeth that were healed at 5 microsurgery (24).
years but not at 1 year. The overall healed rate 5 years after apical Although not a randomized controlled trial, this 5-year study
microsurgery was 8% lower than it was after 1 year, underlining the offered an opportunity to examine the effectiveness of the 3 root-end
overestimated prognosis suggested by short-term studies on apical filling materials; ProRoot MTA (86% healed) was shown to be superior
microsurgery (4). to SuperEBA (67% healed). Several shorter-term apical microsurgery
One tooth-related variable was identified as an outcome studies have reported high success rates using ProRoot MTA ranging
predictor for which the prospective study design provided a high level from 89% to 97% (16, 20, 24, 25, 27–30). Three of these studies
of evidence (1b). Teeth that presented with no or minor interprox- (24, 27, 29) contributed to the conclusion in the recent systematic
imal bone loss both mesially and distally had a higher healed rate review that the success rate of apical microsurgery was 94.5% (6).
than teeth with greater interproximal bone loss (78% vs 53%, respec- In the present study, ProRoot MTA-treated teeth showed the least
tively). This finding corroborated the previously reported adverse regression at 5 years (just under 4%), suggesting the most effective
effect of compromised bone support on the prognosis after apical seal over the longer observation period. Of the teeth treated with
surgery (4, 24, 25). The risk, especially in the longer-term, is that ProRoot MTA, 86% were healed at 5 years. In the absence of any other
an apicomarginal bacterial pathway may develop over time when comparable long-term studies, our results suggested that, at best, the
the crestal bone level is already compromised at the time of apical chance of teeth to heal in the longer-term after apical microsurgery
microsurgery (24). Such communication may not only compromise using ProRoot MTA would be 86%, which is lower than the 94% sug-
periapical healing, but it can also lead to a significant loss of peri- gested in the recent systematic review (6). This suggested prognosis
odontal attachment in the long-term, as observed in teeth that did is far better than that reported in previous 4-year or longer studies
not heal after apical microsurgery (26). Therefore, from the clinical on apical surgery performed with other root-end filling materials and
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TABLE 2. Distribution of the Study from Inception to the 5-Year Follow-up between the root canal and periapical tissues (31), the application of
Retroplast is highly technique sensitive. Possibly, contamination of
Population Subjects Status
the resected root surface or trimming of excess material in some cases
Inception cohort 194 Received treatment may compromise the seal and the prognosis.
Lost to follow-up at 3 Did not attend
1-year examination
Teeth root ends filled with SuperEBA showed the lowest healed
Eligible for 5-year 191 Invited for examination rate (ie, 67%) 5 years after apical microsurgery, which is significantly
follow-up lower than for ProRoot MTA-treated teeth. This 5-year prognosis was
Lost to follow-up 9 1 deceased 10% better than reported in a previous 3-year study (36) but about
at 5 years 2 left country 20% poorer than reported in 2 other long-term studies using SuperEBA
6 did not respond
Teeth extracted 12 11 vertical fracture (23, 37). However, methodological issues, such as the use of the root as
1 prosthetic considerations the evaluated unit in both studies (23, 37) and a large loss to follow-up
Attended 5-year 170 Teeth examined (37), precluded direct comparisons of our results with those of the
examination previous studies (4). Of the 76% SuperEBA-treated teeth that were
healed after 1 year in our previous study (16), 9% showed regression
after 5 years in the current study, which is similar to the 8.5% regression
without emphasis on the microsurgical technique (8, 9, 11, 12, 13, 23). reported 5 to 7 years after apical microsurgery (10). Again, the high
Nevertheless, additional long-term, methodologically sound studies are short-term success rates of up to 97% reported using SuperEBA
required to augment the evidence for the prognosis after apical micro- (6, 16, 37, 20–22, 24) misrepresents the longer-term prognosis.
surgery using ProRoot MTA. Taking into account the absence of clinical signs or symptoms,
Of the Retroplast-treated teeth in this study, about 75% were 85% (145/170) of the teeth were ‘‘functional’’ 5 years after apical
healed after 5 years. This finding corroborated the 6- to 9-year 78% microsurgery although only 76% were healed. The difference of 9%
success rate reported by Yazdi et al (12). This long-term prognosis is between these 2 outcome measures was lower than the 20% difference
poorer than the 73% to 92% reported in the short-term after using (94% and 74%, respectively) reported in the Toronto Study (15).
Retroplast (16, 31–35), suggesting regression over time. Indeed, of Nevertheless, these findings underlined the frequent absence of clinical
the 85% Retroplast-treated teeth that were healed after 1 year in our signs and symptoms associated with post-treatment apical periodontitis
previous study (16), over 9% showed regression after 5 years in the (4, 14, 15) and the importance of radiographic examination to
current study, whereas 6% regression was reported in another long- comprehensively assess the outcome of treatment. According to
term study (12). Although conceptually apical capping with a dentin- Barone et al (15), patients weighing different treatment alternatives
bonded material is expected to seal potential bacterial pathways for teeth with post-treatment apical periodontitis should be informed
TABLE 3. Radiographic Classification of Healing at 5 Years (n = 170) after Apical Microsurgery Related to Classification at 1 Year and the Root-end Filling
Material Used
Healing classification Root-end filling material
1 year 5 years SuperEBA ProRoot MTA Retroplast
Category n* Category n %S n %S n %S n %S
Complete 130 Complete 114 87.7 28 84.8 31 91.2 55 87.3
Incomplete 2 1.5 1 3.0 1 2.9 0 –
Uncertain 7 5.4 3 9.1 1 2.9 3 4.8
Unsatisfactory 7 5.4 1 3.0 1 2.9 5 7.9
Subtotal 33 34 63
Incomplete 11 Complete 2 18.2 1 20.0 1 20.0 0 –
Incomplete 7 63.6 3 60.0 3 60.0 1 100
Uncertain 1 9.1 1 20.0 0 – 0 –
Unsatisfactory 1 9.1 0 – 1 20.0 0 –
Subtotal 5 5 1
Uncertain 22 Complete 3 13.6 1 12.5 1 33.3 1 9.1
Incomplete 1 4.6 0 – 1 33.3 0 –
Uncertain 10 45.5 3 37.5 1 33.3 6 54.5
Unsatisfactory 8 36.4 4 50.0 0 – 4 36.4
Subtotal 8 3 11
Unsatisfactory 7 Complete 1 14.3 0 – 0 – 1 50.0
Incomplete 0 – 0 – 0 – 0 –
Uncertain 0 – 0 – 0 – 0 –
Unsatisfactory 6 85.7 3 100 2 100 1 50.0
Subtotal 3 2 2
Total (n) 170 Complete 120 70.6 30 61.2 33 75.0 57 74.0
Incomplete 10 5.9 4 8.2 5 11.4 1 1.3
Uncertain 18 10.6 7 14.3 2 4.5 9 11.7
Unsatisfactory 22 12.9 8 16.3 4 9.1 10 13.0
Total of healed cases after 5 years (129/170, Table 1) differs from the total number of cases with complete and incomplete radiographic healing after 5 years (130/170) because 1 case with complete
radiographic healing presented with clinical symptoms.
%S, proportion of subtotal filled with given material.
Healing classification according to Molven et al.17
*n excludes 21 subjects lost to follow-up.
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TABLE 4. The Final Logistic Regression Model Identifying 2 Significant Several patient-, tooth-, and treatment-related variables (ie,
Predictors of the Healed Outcome 5 Years after Apical Microsurgery smoking, tooth location, lesion size, 1-sided interproximal bone loss,
Odds Confidence P antibiotic coverage, and postoperative healing course) were associated
Variable ratio interval value with 5-year healed rate differentials of 10% or greater, which are
considered clinically meaningful. According to the multivariate analysis,
Crestal bone level*
(0 = >3 mm,1 = #3 mm) 5.10 1.67-16.21 .017
these variables did not significantly impact the outcome. The lack of
Root-end filling significance might have been caused by uneven distributions of subsets
(0 = SuperEBA, 7.65 2.60-25.27 .003 of the cohort across each variable, but it might also suggest that
1 = ProRoot MTA) the differences might be random.
All other variables listed in Table 1 were rejected in the series of logistic regression models
constructed. Conclusions
*Measured on radiographs from the cementoenamel junction or, if not visible, from the margin of a
This study provided a high level (1b) of evidence for the 5-year
crown or filling.
prognosis after apical microsurgery, with 76% of the teeth healed.
The healed rate was 8% lower than the reported 1-year rate for the
same cohort, with 16 teeth (12% of the cohort) regressing and 5 teeth
about the high probability of retaining asymptomatic function 5 years
(3% of the cohort) progressing from the first to fifth year after treat-
after apical microsurgery even if radiographs do not suggest the teeth
ment. One tooth-related outcome predictor was identified: the healed
to be healed. Such information can assist the patients, especially
rate was higher when the mesial and distal interproximal bone level
those experiencing preoperative symptoms, in relating the pro-
was #3 mm from the cementoenamel junction (or restoration
jected outcomes to their individual values and in setting specific
margin). Another treatment-related outcome predictor was supported
goals they hope to achieve by having the teeth treated by apical micro-
by a lower level of evidence (2b): the healed rate was higher for root-
surgery.
end fillings with ProRoot MTA (86%) than with SuperEBA (67%). There
As highlighted earlier, this longitudinal study provided insight
is an urgent need for additional prospective studies to augment the
into the dynamics of healing and its regression beyond the first
evidence for the long-term prognosis of apical microsurgery and to
year after apical microsurgery, suggesting overestimation of the prog-
assess the root-end filling materials and other intervention aspects of
nosis by short-term assessment. In previous longitudinal studies in
apical microsurgery at high-level evidence.
which treatment was not consistent with apical microsurgery (6),
the 1-year assessment predicted the 5-year prognosis with an accu-
racy of 91% (7) and 95% (8), which is similar to the 95% predictive Acknowledgments
accuracy reported in a current 6- to 9-year study (12) and the 90% The authors thank Dr. J€rg H€sler and Kasper Stucki, Institute
u u
predictive accuracy reported herein. In the longer-term, regression of Mathematical Statistics and Actuarial Science, University of
from healed to nonhealed in some teeth (16 in the present study) Bern, Bern, Switzerland, for the statistical analysis.
is partially offset by continued healing of fewer teeth (5 in the present The authors deny any conflicts of interest related to this study.
study) that are not healed in the short-term. Thus, the short-term
outcomes of apical microsurgery cannot be taken as reported
because they overestimate the long-term prognosis, but they can References
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JOE — Volume 38, Number 5, May 2012 5-Year Outcome of Apical Surgery 579