initial endodontic therapy outcomes: a na val - DTIC

INITIAL ENDODONTIC THERAPY OUTCOMES: A NA VAL

POSTGRADUATE DENTAL SCHOOL ANALYSIS

by Jason L. Hicks

Lieutenant Commande1·, Dental Corps United States Navy

A thesis submitted to the Faculty of the Endodontics GI'aduate Program

Naval Postgraduate Dental School Uniformed Services University of the Health Sciences

in partial fulfillment of the requirements fo1· the degree of Master of Science in Oral Biology

June 2018

Naval Postgraduate Dental School Uniformed Services University of the Health Sciences

Bethesda, Maryland

CERTIFICATE OF APPROVAL

MASTER'S THESIS

This is to certify that the Master's thesis of

Jason L. Hicks

has been approved by the Examining Committee for the thesis requirement for the Master of Science degree in Oral Biology at the June 2017 graduation.

Research Committee: CAn~ Thesis Supervisor and Chail'man, Endodontics

The authol' hereby certifies that the use of any copyrighted material in the thesis manuscript titled:

"INITIAL ENDODONTIC THERAPY OUTCOMES: A NAVAL POSTGRADUATE DENTAL SCHOOL ANALYSIS"

is appropriately acknowledged and, beyond brief excerpts, is with the permission of the copyright owner.

Jason L. Hicks Endodontics Graduate Program Naval Postgraduate Dental School June 2018

NAVAL POSTGRADUATE DENTAL SCHOOL JASON L HICKS

2018

This thesis may not be re-printed without the expressed written permission of the author.

iii

Distribution  Statement    

Distribution  A:  Public  Release.      The  views  presented  here  are  those  of  the  author  and  are  not  to  be  construed  as  official  or  reflecting  the  views  of  the  Uniformed  Services  University  of  the  Health  Sciences,  the  Department  of  Defense  or  the  U.S.  Government.  

ABSTRACT

INITIAL ENDODONTIC THERAPY OUTCOMES: A NAVAL POSTGRADUATE DENTAL SCHOOL ANALYSIS

JASON L. HICKS D,D,S., ENDODNTICS, 2018

Directed by: CAPT Terry Webb, D.D.S., M.S. Naval Postgraduate Dental School

Introduction: Initial non-sm·gical rnot canal treatment (NSRCT) has been examined with

multiple endodontic studies and shown to be associated with high clinical outcomes. Numerous

patient and treatment variables affecting endodontic outcomes have been identified. However,

few studies have examined military populations. This retrospective study evaluated the outcomes

and affecting factors of initial NSRCT performed by U.S. Navy Endodontists and endodontic

residents, Methods: 600 subjects, that received root canal therapy, had follow-up examinations

performed at a minimum of 1-year post treatment, Clinical and radiographic data were obtained

from the initial NSRCT appointment at the follow-up examination. Data were analyzed using

Fisher's Exact test to determine the healed rate and odds ratios to evaluate the influence of

covariate factors on endodontic outcomes. The endodontic outcome was calculated as healed

and functional. Healed was defined as the absence of a radiographic lesion and no clinical

symptoms. Functional was defined as the complete absence of clinical symptoms. Results:

Analysis determined the healed rate to be 72.0% and the functional rate to be 93, 1 %, Further

analysis revealed a negative effect on endodontic outcomes for those subjects presenting with a

pre-operative sinus tract, a pedapical lesion, lesions larger than 5 mm, a diagnosis of pulp

necrosis, and teeth that experienced procedural complications. Conclusions: Retrospective

analysis of initial NSRCT indicated a healed rate of 72.0% with a functional rate of 93, 1 %. The

pre-treatment status of the tooth was found to be the most significant predicto1· of endodontic

outcomes.

Iv

TABLE OF CONTENTS

Page

LIST OF TABLES..................................................................................................... vi

LIST OF FIGURES................................................................................................... vii

CHAPTER

I. REVIEW OF THE LITERATURE ........................................... .. 1

II. MATERIALS AND METHODS ... ,,,,, .. , ..... ,,,,.llltllllllllllfllt;,,, ••••.• 5

III. RESULTS .......... , .................. , ,, ,,,11 • 111111 I,,, ••• ,,,, •...••. , •••••••.•.•• ,,,,,,,,, 12

IV. DISCUSSION., ........................ ,, ................................................. . 13

v. CONLUSIONS ................... ,.,,,,.,.,,.,,,,,., .............. , ............... ,,,,,,,, 17

REFERENCES 11 • 1tttHttt1•••••••••ttttlttt • ttt1•••• .. •••••••t111tlttl • t1tltllllll••••••••••••••••••••ttlttttllttll 18

V

Table

1.

2.

LIST OF TABLES

Statistical Analysis Performed and Vatiables Evaluated .......................... ..

Variables with Significant Effect on Outcome .......................................... .

vi

Page

11

12

Figure

1.

2.

3.

4.

LIST OF FIGURES

[Outcomes Patient Information] ..... , , .. , ....... , .. , , ... , , , ......................... , . , .... , ... ,

[Outcomes Patient Preoperative Data] ............ , ... , .......................... , ........ , ...

[Outcomes Intraoperative Data] .............. ,., ....... ,.,., ...... , .................. , .. , ....... .

[Outcomes Follow-up Data] ...................... " ... , ....................... , .................. ,

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Page

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8

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I. REVIEW OF THE LITERATURE

Non-sm·gical l'oot canal therapy (NSRCT) preserves a tooth that might othel'wise be lost

to extraction. Initial endodontic therapy is the most common type of treatment l'endered by

endodontists and over 15 million NSRCTs are performed annually in the US (1). The goal of

the dental community is to provide the highest level of cal'e fo1· all patients. Achieving that goal

l'equil'es continuous evaluation and assessment oftl'eatment outcomes.

Methodologies used to assess endodontic treatment outcomes have included bacteriologic

testing, histologic evaluation, cone beam computed tomography (CBCT), and periapical

radiographs. Evaluating treatment outcomes and disease using bacterial culttll'ing or genetic

testing is desirable but problematic because many bacterial species are difficult or even

impossible to culture (2). Histologic evaluation provides effective insight into health and disease

at the cellular and tissue level. However, this method l'equires tooth extraction or tissue

sampling, and is therefore impractical for routine assessment ofpulpal and periapical tissue,

CBCT is advancing as an effective tool for assessing both osseous lesions and anatomy in more

detail than traditional pel'iapical radiography. However, CBCT imaging is not cru'l'ently

indicated for all initial root canal treatment according to AAE/ AAOMR radiology guidelines (3).

Therefore, pre-treatment and post-treatment CBCT studies have not yet been conducted with

large numbers of clinical subjects. Many studies have evaluated larger numbers of patients by

combining clinical symptoms with periapical radiographic findings ( 4).

Strindberg was one of the first to define NSRCT success using a combination of clinical

and radiogrnphic evaluation, In 1956, Strindberg reported a successful outcome rate of initial

NSRCT of 86%. Therapy was determined successful if teeth were asymptomatic, the

periodontal margins were normal, or if periodontal contours were only widened around an

1

overfilled canal. Therapy was determined a failure if the tooth had clinical symptoms, had been

extracted, or had a periapical radiolucency that either remained the same size or increased in

size. Strindberg admitted the existence of limitations in this appmach, and therefore later studies

incorporated different factors and methods for determining success (5).

Radiographs have played a significant role in evaluating NSRCT outcomes, and their use

in clinical assessment has changed ove1· the years. Brynolfs cadaver study demonstrated a

radiograph's ability to distinguish lesions in the pel'iapical tissue with that of the histological

findings; nonetheless, she stated radiographs are not without their shortcomings (6). A lack of

co11·elation between radiographic, clinical, and histopathologic findings in their endodontic

surgical specimen study was noticed by Block et al (7), Green attempted to cor1·elate the

periapical region of root canal treated teeth with histologic findings in 29 cadaver specimens.

The radiographs were generally consistent with the histology, however 26% of specimens

deemed mdiographically normal, were found to have histologic inflammation (8). Building upon

Brynolf s work, Orstavik et al. developed the Periapical Index (PAI) scoring system which

correlated histological cadaver findings with a proposed category (9). This radiographic

interpretation categorizes healing ranging from a "normal apical periodontium" to "radiolucency

with radiating expansions of bone" using five possible scores:

1. Pedapical destruction of bone almost definitely not present

2. Periapical destruction of bone probably not present

3. Unsure

4. Periapical destmction of bone probably present

5. Periapical destruction of bone almost definitely present

2

PAI scoring has been further summarized, scores of 1 or 2 are indicative of success, a

score of 3 designates a radio graph of inadequate diagnostic quality, and a 4 or 5 demonstrates

treatment failure. This provides an internal standard of reference and a reliable and reproducible

result (10), Numerous subsequent studies have incorporated PAI scoring to assess endodontic

outcomes (11-13), Though not perfect, the introduction of this scol'ing system increased

standardization of radiographic interpretation in outcome analysis.

Another challenge in comparing the outcomes ofNSRCT studies is seen in the varying

definitions of success and failure. Examples of diverse reporting criteria include results defined

as strict healed rate, loose healed rate, healing, and/or functional. Success defined by strict

criteria is when a tooth is completely free of clinical symptoms and without a measurable

radiographic lesion. The presence of symptoms or a radiographic lesion would be considered a

failure utilizing strict criteria. Ray and Trope, for example, reported a success rate of 61. 7%

using strict criteria (13). Outcome studies applying loose criteria to define success account for

teeth undergoing healing as evidenced by a diminishing radiographic lesion while remaining

clinically asymptomatic. Studies conducted in North America tend to report findings in terms of

loose criteria (4). Peak et al reported 57% success under strict cdteria and 85% success under

loose cdteria and Penesis et al found 68% success by stl'ict and 83% success by loose cdteria

(14, 15). Molander et al. reported very similar outcomes; 70% success using strict and 90%

success using loose criteria (16), In 2011, Ng et al. found 83% and 89% success by strict and

loose criteria respectively (17). However, variations even exist within the strict and loose

categorizations. The Toronto Studies excluded patients with the clinical symptom of tenderness

to percussion in their definition of strict criteria failures. They reasoned this symptom could

3

result from conditions other than a failing l'oot canal. This multi-phased study reported a success

rate of 86% by stl'ict cl'iteria with a 95% functional rate (11),

Varying definitions used to indicate success and failure ofNSRCT add value to the

results of a pa1ticular study but make meaningful comparisons between studies difficult and can

be misleading when unfamiliar with the criteria used to define the endodontic outcome. In an

attempt to make om· findings comparable to othe1·s, this study utilized the common radiographic

assessment methodology of PAI scoring and reported outcome results with a strict healed rate as

well as a functional rate.

In addition to reporting the outcomes of initial endodontic therapy, many studies have

investigated variables that significantly influence those outcomes. Existing literature is divided

on what effect pre-existing health conditions of the patient have on endodontic outcomes.

Several studies have repo1ted factors such as diabetes, smoking, and hea1t disease significantly

impact endodontic outcomes (18, 19) while others have not (20, 21), The literature is also

divided on the effect of pre- and peri-operntive status of the tooth. For instance, pulpal status has

been shown to be significant in some studies (12, 20) but not in others (22). Also, the presence

of a pre-operative lesion affected outcome in several studies (12, 17, 20) but not in others (20),

This clinical investigation examined multiple covariate factors and theh potential effect on

clinical outcomes.

No previous study has evaluated the outcome of initial root canal treatment within an

American milital'y population. The primary purpose of this retrospective study was to evaluate

the outcome of initial non-surgical root canal treatment pe1formed by U.S. Navy Endodontists

and t'esidents. A secondary purpose was to report variables that affect the outcome of initial non­

surgical root canal treatment.

4

II. MATERIALS AND METHODS

This observational study combined clinical data obtained from a follow-up examination

and retrospective data gathered from the subject's record at the time of treatment. The materials

and methods were taken from the Walter Reed National Military Medical Center Institutional

Review Board (IRB) approved protocol #352272. Study subjects were recruited from eligible

beneficiaries at the Naval Postgrnduate Dental School (NPDS) Endodontic Clinic meeting the

following criteria:

Inclusion Criteria: Adults (18 years or older) who received initial non-surgical

endodontic treatment solely by an endodontic resident at NPDS or a Navy Endodontist.

Treatment must have been completed in at least the 12'11 month prior to a follow-up

examination. A periapical radiograph, taken at the obturation appointment, must have

been available for considerntion as a study patiicipant.

Exclusion Criteria: Patients whose 1·ecord did not include an obturation radiograph,

treatment data, 01· whose treatment was completed less than the 12th month prior to

follow-up examination were excluded. Also excluded were patients who received non­

surgical retreatment, surgical treatment, extraction, or canal obturation using Resilon,

canier-based, silver points, or a paste fill technique. Additionally, if any portion of the

treatment was performed by any provider who was not a Navy Endodontist 01· Navy

Endodontic Resident, the patient was excluded,

Informed consent was obtained from all study pa1iicipants. Once enrolled, the following

pre-existing data were collected from the patient's treatment record: pre-operative data collected

at initial examination, intra-operative data, and immediate post-treatment radiographs taken at

5

obturation. Pre-operative data collected included: date of bhth, gender (Fig 1), pulpal and apical

diagnosis, presence/absence of symptoms, tooth type (single versus multi-root), and existing

medical conditions (smoker, col'Onary heart disease, diabetes) (Fig 2). Intra-operative treatment

data gathered included: single vs. multiple treatment sessions, intracanal inigants and

medications, procedural complications, obturation fill length, pel'iradiculal' status, and placement

of an intl'a-orifice barrier (Fig 3).

The follow-up examination of each subject consisted of a thorough clinical evaluation

and a minimum of one periapical radiograph of the treated tooth. The evaluations were

perfo1med by collaborated study investigators; NPDS endodontic residents supervised by Board­

ce1tified staff endodontists. The follow-up data gathered included presence/absence of

symptoms, apical diagnosis, presence of coronal restoration, presence of intra-canal post,

pel'iradicular status, and the length of the follow-up period (Fig 4). In subjects with multiple

treated teeth, each tooth was given a different project number and the identical clinical and

radiographic exam was conducted for each tooth.

The pe1iradicular status of both immediate post-treatment and follow-up radiographs

were assessed by calibrated board-ce1tified endodontists. All radiographs were de-identified by

assigning random numbers. In order to avoid reviewer bias during evaluation, the final treatment

radio graphs were viewed separately from the follow-up radiographs. The periapical index (PAI)

scoring method was used while viewing the images on a reseal'Ch designated laptop. The laptop

allowed for the adjustment of brightness and contrast of each image as the reviewer scored the

radio graph. The evaluato1·s were calibrated using selected radio graphs and a PAI standard

refel'ence, The radio graphs were scored according to the PAI system as healed (scores 1 and 2),

undetermined (score 3), or diseased (scores of 4 and 5). The evaluators also scored the

6

obturation length as short, flush, or long in l'efel'ence to the 1·adiograpic apex. Each evaluator

scored the images independently, and in the case of disagreement, the final score was decided via

forced-consensus.

A power analysis was conducted using an estimated healed rate of 85% with a 0.03

tolerance mal'gin of errol' produced a sample size of 545 (11). Factoring in a 10% exclusion rate,

the subject population was set at 600.

Data Analysis: Once the data was collected, forty-seven variables were analyzed using

the SPSS program to determine any significant effects on treatment outcome. Statistical analysis

performed included logistic regression, Fisher's Exact test, and Odd's Ratios (Table 1).

7

.. , .. ,_"""_)fo.st, (YIN) .. . , , · Cai'ies : · · ·

·.":,ti\1

;::\.\:;!ii'\'.::.:,._:,

Diabetes Type:

... · · Ool4 ~~11sitivity (R/NL; R/L; NR) · . ·t~rc:µ~siqµ seµsitivity (SINS) • fy!p~ility (Miller's Class)

, a1~e441g 011 })l'o oillg . · : : f!j#to1i:Crf1:>Iiachh1g (YIN) : . ~si<;>ry of J11t<;,i·nal resorption (YIN) ' '\~~fr~at111ent (Y/N) ···. , :~µrglcal/11onsµrgical treatment > < Op~11 margin (Y/N)

. • ~llestoratjop p1·e$ent (YIN) ···:·:1)µ1;aiton9fsymptoms (mos.)

mm

A,pipAl:. : . . . . .· . · <: <l'{qr111,alJip1cal tissues . .• Sympt9n;i~ti9 ~piGal periodontitiis • ii J\sy111pto11JJ1tic apical pel'iodontitis · A,qµte apic:al abscess

.: >., <.'<:Jlii:9Jic apical abscess I · · iC!qp,4e,nstng Qsteitis

'J)esip11 of11on endodontic origin

8

• ·.. . y\pi6it: . . .··. . ·· · · · •.,: < · '· Nol'lnal apical tissues

-.-. - ... Syniptpmatic apical periodontitis A~ym,ptot11atic apical periodontitis

. ·. . . . A9uti apical abscess . • ·. • · \ .' ¢J»·Q11ip apic~Labscess . . . . . . Qo11~~~~i11g osteitis

Lesi()n of' no.Q. endQdontic origin .-,--- ' .. ·•·· ., . . ...

9

Symptoms: YIN __ Pain (0-10) __ Cold sensitivity (R/NL, R/L, NR)

EPT __ Percussion sensitivity (SINS) __ Palpation sensitivity (SINS) __ Mobility (Miller's Classification) __ Sinus tract (YIN) __ Periodontal Screening Record (PSR) __ Swelling (YIN) __ Bleeding on probing __ Time Elapsed Between Initial Tx and Pe1manent Restoration __ Duration of symptoms

Follow-up diagnosis: (Apical) __ Normal apical tissues __ Symptomatic apical pel'iodontitis __ Asymptomatic apical periodontitis __ Acute apical abscess __ Chronic apical abscess __ Condensing osteitis

Lesion of non-endodontic origin

10

Caries present? YIN Permanent coronal restoration present? YIN Intracanal post present? YIN Open Margin YIN Surgical or Nonsurgical Treatment

11

III. RESULTS

This analysis consisted of 600 emolled subjects. 48 were missing pre- or ped-opel'ative

data or did not meet eligibility requirements and were therefore excluded after emollment.

The final number for descriptive and clinical analysis was 552 subjects. 9 subjects were

excluded because they received a radiographic PAI score of 3 (unsure) and lacked symptoms.

This resulted in a total of 543 subjects included fo1· the healed rate analysis. However, those 9

subjects were analyzed for the functional rate analysis because they were asymptomatic.

Of the 543, 371 subjects (68%) were male and 172 subjects (32%) were female. Ages ranged

from 19 - 84 years, and the median age was 48, The median follow-up time was 13 months with

a rnnge from 11.03 months to 100 months (8.3 years). Among the 543 subjects for final outcome

analysis, 391 (72.0%) were healed with a 95% confidence interval of 68%-76%, and 152

(28.0%) were non-healed. Five val'iables were noted to significantly affect outcome: presence of

a sinus tract, presence and size of a pre-operative l'adiographic lesion, non-vital pulp, and

procedural complications listed in (Table 2). A functional rate was determined to be 93 .1 %.

12

IV. DISCUSSION

This observational retrospective study assessed the outcome of initial NSRCT via clinical

and radiogl'aphic examination at the follow-up appointment. There is a great degree of

variability between the outcomes reported in endodontic literature. Several investigational

factors can contribute to these differences, such as methodology, follow-up times, or the criteria

used to define the outcomes.

This study defined healed as those with a PAI score of 1 or 2 and being free of any

symptoms (percussion, palpation, cold sensitivity). This is commonly referred to as "strict

criteria." The strict healed rate for this investigation was 72.0% (391/543) with a 95%

confidence interval of 68%-76%. A 1·eview by Ng et al. reported a pooled healed rate of 5

investigations using strict criteria with a 12 month recall resulting in a weighted healed rate of

67.7% (4).

Another definition for healed/healing is known as "loose criteria." Loose criteria combines

teeth considered healed by strict critel'ia and adds teeth demonstrating a dec1·ease in lesion size.

In some studies, the presence of a lesion demonstrating a reduction in size is specifically

differentiated as "healing" from the rest of the "healed" subjects (20), while others don't make

that distinction, reporting only loose criteria results as one combined number (23). In the present

study, lesion size was not specifically indexed for loose criteria. However, when incorporating

those PAI scores that improved from 5 to 4 at the one-year follow-up, an underestimated "loose''

healing rate of 79.6% is determined for this study, We consider this percentage underestimated

since it does not include all lesions that may have decreased in size in the "loose" healed mte.

Some lesions decreased in size, yet still received a PAI score of 5, therefore could not be

included in the "loose" healing rate.

13

This investigation's functional rate was 93%, with a 95% confidence interval of 91 %-95%.

Just as criteria fo1· defining "healed" rate varies among outcome studies, definitions for

"functional" rates have been shown to differ as well. For example, in one particular study,

DeChevigny et al opted to not include percussion sensitive subjects as symptomatic if they were

free of any other symptoms, Their justification was simply stated and reasonable, percussion

sensitivity can be from a non-endodontic source (11). In this study, 21 out of the 38

symptomatic subjects at follow-up had percussion as the only symptom. If those subjects were

excluded from the number of symptomatic patients, the comparable functional rate would have

been 96.9%. However, we chose to only consider completely asymptomati_c teeth as being

functional.

Five different variables (Table 2) were noted to be predictors of non-healing, The presence

of a pre-operative sinus tract had the strongest odds ratio with only 19.2% shown to be healed

at the follow-up appointment. This was in agreeance with the study by Ng et al who also found

the presence of preoperative sinus tracts to decrease healing to 66. 7%, yet not to the extent that

this study revealed. One possible reason could be the number of sinus tracts analyzed; 141 sinus

tracts were present in their study, whereas this investigation had a smaller number at 26 (17).

The presence of a preoperative lesion yielded a healed rate of 53%, while the absence of a

preoperative lesion healed 83.3%. This was consistent with Cotton, who reported a 33%

difference, however Swartz et al and DeChevigny et al. were lower at 11 % and 12% respectively

(11, 12, 23). When relating lesion size to healing, larger lesions have been reported to reduce

healed rates, Hoskinson et al. identified an 18% decrease in healing for each millimeter increase

of the preoperative lesion. Matsumoto et al. also found decreased healing rates when a

preoperative lesion presented >5mm (24, 25), Likewise, this investigation reported lesions

14

>4mm were 6.6 times less likely to heal. However, one potential limitation in this study could

have been the method for lesion measurement was not standardized. Non-vital pulp diagnosis

revealed a healed rate of only 57%, whereas vital teeth healed at a rate of 81.6%. Pulpal status

has been reported to be a predictor of healing in numerous other studies (12, 20, 26). This

investigation found a healed rate for teeth with a procedural complication to be 53.5%.

Fractured instruments, non-instrumented canals due to calcification, and perforations were the

most common reported procedural complications, DeChevigny et al. and Azim et al. also

reported procedural complications to be significant (11, 20).

Another key investigational factor in assessing endodontic outcomes is the length of time

between treatment and outcome assessment. Strindberg proposed that follow-up examinations

should be conducted at 6-month intervals during the first 2 years and every year thel'eafter (5).

Sjogren stated, "The recovery of the periapical tissues to a healthy condition is a dynamic

process and it is possible that a premature evaluation ofperiapical healing might include teeth in

which the repair process has not yet stabilized" (27), Friedman proposed 90% of teeth that

would eventually heal following NSRCT may take up to 5 years, However, only 50% of those

would be completely healed after 12 months (27).

Follow-up time is one of the greatest variables in outcome study design, and has been shown

to significantly impact the outcome rate of studies with a strict criteria ( 4). The follow-up time

for this study was a minimum of 1 year, with the median follow-up time of 13 months. The

overall healed rate by strict criteria was 72%. A study by Peale et al., with a similar 1-year

minimum follow-up using strict criteria, reported a healed rate of 57% (14). A review by Ng et

al reported a pooled healed rate of 5 investigations using strict criteria with a 12 month recall rate

resulting in a weighted healed rate of 67.7% (4). With an increased follow-up time, there is a

15

trend toward increased healed rates seen in outcomes literature. For example, a 2 to 4-year study

by Ng and others reported a healed rate of 83% (17). DeChevigny et al had a 4 to 6-yea1· follow

up period with a reported healed rnte of 86%. Therefore, by extending the follow-up period of

10-17 years to 20-27 years, Molven et al discovered an additional 11 % healed rate (28),

With a closer look at this investigation's results, that trend of increased healing over time

can be observed as well. 64 subjects analyzed from the current study had a follow-up period of 2

years or greater. The strict healed rate for those 64 subjects improved to 75%. The trend can also

be observed when examining the subpopulation of subjects with a pre-existing lesion. 151 teeth

with a pre-operative radiolucency were evaluated at the 1-year follow-up exam, and 54.3% were

fully healed. This finding is similar to Orstavik's prospective analysis which found 51 % of cases

fully healed after 1 year (29). In this study, over 40% of the cases that had not fully healed at 1

year showed definite signs of healing, with the PAI score improving from a 5 to a 4 in 45 of 109

possible cases. Orstavik observed continued healing as well, with that study reporting 88% of

the subjects were healing at the 12 month time interval, with complete healing observed up to 4

years in some cases (29). The 13-month median follow-up time is a limitation to this

investigation because it was not possible to calculate a healed rate at longer time intervals.

However, there are two observable trends in this study, the first was extending the follow-up

time to 24 months yielding an incl'eased healed rate of 7 5%. The second was 41 % of non-healed

lesions improved their PAI score, indicating an increased follow-up time for this study would

likely yield an increased healed rate as seen in longer-term outcome investigations.

Another observed trend from this investigation is related to the statistically significant

variables that were shown to affect outcomes. Teeth presenting with sinus tracts were the least

likely group to be healed at 1 year, followed by large lesions (>4mm), any size lesion, and

16

necrotic pulp (sinus tract> large lesion> any size lesion> necrotic pulp), It was noted that

chronic apical abscesses were least likely to heal and noticed a continual improvement in healed

rate from the presence of a lesion to necrosis without a lesion, Therefore, the more chronic the

infection, the less likely the lesion is to be healed at a 1-year follow-up.

V. CONCLUSIONS

The outcome of initial non-surgical root canal treatment by Navy endodontists and

residents was noted to be 72.0% healed rate with a 93, 1 % functional/clinical success rate,

Factors with a negative impact on outcome included presence of a sinus tract, presence and size

of a pre-operative radiographic lesion, non-vital pulp, and procedural complications,

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REFERENCES

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