Invest Clin 64(1): 5 - 14, 2023 https://doi.org/10.54817/IC.v64n1a01

Corresponding author: Jairo Mariel Cárdenas. Programa de Postgrado en Ciencias Dentales, Facultad de Estoma-

tología, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava 2, Zona Universitaria, San Luis Potosí, SLP,

México. Phone: +52 (444) 4973830. Email: richiendo@gmail.com

Correlation between bacterial type/bacterial

quantity and bone loss detected by cone

beam computed tomography (CBCT)

in primary endodontic infections.

Ricardo Oliva Rodríguez1, Georgina Yaretzy Rangel Galván1, Ana María González

Amaro1, Francisco Javier Gutiérrez Cantú2, Abraham Israel Muñoz Ruiz2,

José Obed García Cortés2 and Jairo Mariel Cárdenas2

1Programa de Postgrado en Endodoncia, Facultad de Estomatología, Universidad

Autónoma de San Luis Potosí, San Luis Potosí, SLP, México.

2Programa de Postgrado en Ciencias Dentales, Facultad de Estomatología, Universidad

Autónoma de San Luis Potosí, San Luis Potosí, SLP, México.

Keywords: bone loss; cone beam; primary endodontic infection.

Abstract. Periapical lesions (PL) of endodontic origin are one of the most

common pathological conditions that affect peri-radicular tissues. The main ob-

jective of this study was to evaluate the amount and species of microorganisms

isolated from necrotic pulps, establish a correlation between these and the size of

periapical lesions, and how the amount and species of microorganisms decreased

with non-surgical root canal treatment. Twenty-seven patients with a clinical diag-

nosis of dental pulp necrosis and chronic periapical lesions were selected; a Cone

Beam Computed Tomography (CBCT) and microbial samples of the root canal

system were taken previous to a disinfection protocol, a post-instrumentation/

disinfection protocol, and a post-medication placement. Samples were processed

for colony-forming unit (CFU) counting, Gram staining technique, and bacterial

identification by the API-20 Strep/API-20A system. The API system identified 21

species of microorganisms in the pre-instrumentation samples, 11 species in the

post-instrumentation samples, and 11 in the post-medication samples. There was

a correlation coefficient of 0.598% between the initial size of the lesion and the

number of bacteria, with a coefficient of determination up to 35.7%, a correla-

tion coefficient of 0.486% and a determination coefficient of 23.6% between the

size of the periapical lesion and the number of CFUs. This study contributes to

the knowledge of the amount and species of microorganisms isolated and identi-

fied from necrotic pulps, establishes a correlation between the amount and spe-

cies of microorganisms and the size of the periapical lesions, and shows how the

decrease of microorganisms contributes to the healing of PL, corroborating the

importance of an adequate disinfection protocol.

6 Oliva Rodríguez et al.

Investigación Clínica 64(1): 2023

Correlación entre el tipo y cantidad de bacterias y la pérdida

ósea detectada por Tomografía Computarizada de Haz Cónico

(CBCT) en infecciones endodóncicas primarias.

Invest Clin 2023; 64 (1): 5 – 14

Palabras clave: pérdida ósea; haz cónico; infección endodóncica primaria.

Resumen. Las lesiones periapicales (LP) de origen endodóncico son la

condición patológica más común que afectan los tejidos perirradiculares. El ob-

jetivo principal de este estudio es evaluar la cantidad y especie de bacterias ais-

ladas de pulpas necróticas, correlacionar la cantidad y especies bacterianas con

el tamaño de la lesión, y cómo disminuyen la cantidad y especies de microor-

ganismos con el tratamiento de conductos. A 27 pacientes con diagnóstico de

necrosis pulpar y lesión periapical crónica detectada con CBCT se les tomaron

muestras microbianas del sistema de conductos antes y después del protocolo

de desinfección y de la medicación intraconducto. Las muestras se procesaron

para el recuento de unidades de formación de colonias (UFC), tinción de Gram

e identificación mediante el sistema API-20 Strep/API-20A. Se identificaron

21 especies en las muestras pre-instrumentación, 11 en las muestras post-ins-

trumentación y 11 en las muestras post-medicación; se observó un coeficiente

de correlación del 0,598% entre el tamaño inicial de la lesión y la cantidad de

bacterias, con un coeficiente de determinación hasta el 35,7%, un coeficiente

de correlación del 0,486% y un coeficiente de determinación del 23,6% entre

el tamaño de la lesión periapical y el número de UFCs. Este estudio contribuye

al conocimiento sobre la cantidad y especies de microorganismos aislados e

identificados a partir de pulpas necróticas, establece una correlación entre la

cantidad y especies de microorganismos y el tamaño de las lesiones periapicales

y exhibe cómo la disminución de microorganismos contribuye a la curación de

LP, corroborando la importancia de un adecuado protocolo de desinfección.

Received: 18-05-2022 Accepted: 26-09-2022

INTRODUCTION

Periapical lesions (PL) are one of the

most common pathological conditions that

affect peri-radicular tissues in the alveolar

bone 1,2 and are mainly classified as radicular

cysts or dental granulomas 1,3-5. The micro-

bial invasion and subsequent infection of the

root canal system play a decisive role in the

initiation, progression 1,4, and establishment

of peri-radicular conditions4 since bacteria

and their by-products act as antigens that

elicit a non-specific inflammatory response

as well as specific immunological reactions

in the peri-radicular tissues 2.

The bacterial species present in the

apical region may have a significant role in

the pathogenesis of apical periodontitis 6.

Gram-negative bacteria predominate in the

root canal system of teeth with pulp necro-

sis and PL 6. Some bacterial virulence factors

include the structural components and prod-

ucts of bacterial metabolism 6. It has been

established that the levels of endotoxins in

root canal infections are directly related to

the severity of peri-radicular bone destruc-

Correlation between bacterial type and quantity and bone loss detected by CBCT 7

Vol. 64(1): 5 - 14, 2023

tion 7. Lipopolysaccharides (LPS) that form

part of the bacterial cell wall and act like

endotoxins are especially important in end-

odontic infections because of their biologi-

cal effects, which lead to a complex interplay

with host factors 6, like chemical mediators

of inflammation, including the cytokines IL-

1a, IL-1b, TNF-α and prostaglandins related

to the pathogenesis of periapical lesions 5,

resulting in clinical symptomatology, inflam-

matory reaction, and resorption of miner-

alized tissues6. Also, teichoic acid (TA) and

lipoteichoic acid (LTA) are present in gram-

positive bacteria and share their pathogenic

properties with LPS, resulting in well-known

injuries to the dental pulp and periapical tis-

sues 6.

Most PL (>90%) can be classified as

dental granulomas, radicular cysts, or ab-

scesses 3, but the precise nature of such

lesions can only be determined histologi-

cally; for this reason, the true prevalence of

each pathological condition is unclear 5. PL

should be treated initially by a non-surgical

approach 1. The purpose of the non-surgical

root canal treatment is to shape and clean

the root canal system 1,4 to eliminate the ne-

crotic tissue and infective bacteria and their

antigens1, and finally seal the root canal sys-

tem three-dimensionally to prevent reinfec-

tion 4. PL usually heals as a response to me-

ticulous non-surgical endodontic treatment

4. The primary root canal treatment yields

predictable results with a survival rate of

95% after a 4-year follow-up 4. To assess the

healing potential of a PL, a period of 6 to 12

months after root canal treatment should be

considered, while complete healing of the PL

lesion might take up to four years. However,

treatment failure is possible due to different

microbial and non-microbial factors 4, lead-

ing to persistent intra- or extra-radicular in-

fection, and a surgical procedure should be

considered 1.

Nowadays, histopathological evaluation

is the gold standard for diagnosing PL, but

CBCT, MRI, and echography show promising

results in differentiating granulomas and

cysts 4. In addition, CBCT offers relatively

high-resolution and isotropic images. Po-

tential applications in endodontics include

diagnosis and evaluation of most aspects of

endodontic treatment, such as determina-

tion of the configuration and length of the

root canal, presence of accessory canals, and

PL evaluation 8.

The main objective of this study was to

evaluate the amount and species of microor-

ganisms isolated from necrotic pulps, estab-

lish a correlation between these and the size

of periapical lesions; and to determine how

the amount and species of microorganisms

decreased after the non-surgical root canal

treatment.

METHODS

This study was evaluated and autho-

rized by the Research Ethics Committee of

the Faculty of Stomatology, UASLP, with the

code CEI-FE-019-016.

Twenty-seven systemically healthy pa-

tients (18-60 years old) with a clinical di-

agnosis of dental pulp necrosis and chronic

PL associate (primary endodontic infection)

were selected for the study.

Microbial identification

Microbial samples of the root canal sys-

tem were taken from each tooth previous to

disinfection protocol, post-instrumentation/

disinfection protocol, and post-medication

placement.

Before each clinical procedure, the area

of intervention was cleaned with a brush and

Viarden® prophylactic paste (Viarden SA de

CV, Mexico). Next, each patient was anesthe-

tized with mepivacaine HCl 2% + epineph-

rine 1:100000. A rubber dam was placed and

sealed with LC Block Out in the enamel rub-

ber dam interface. The dental pulp chamber

access was performed using a carbide bur

#2, then the operative field was disinfected

with hydrogen peroxide 30% (Fermont, Pro-

ductos Químicos Monterrey SA de CV, Mexi-

co) for 1 minute, sodium hypochlorite 2.25%

8 Oliva Rodríguez et al.

Investigación Clínica 64(1): 2023

for 1 minute, and finally the solutions were

inactivated with the application of sodium

thiosulfate 10% for 1 minute (Fermont, Pro-

ductos Químicos Monterrey, México).

The endodontic working length was

established using an apex locator ID (Syb-

ronEndo, Kerr Corp. USA); then the pre-in-

strumentation bacterial sample of the root

canal system was taken; after, the root canal

was instrumented with Protaper Next rotary

system (X1, X2, X3) (Dentsply Sirona, USA).

The final irrigation protocol was used as fol-

low: 2 mL of EDTA 17%, followed by 2 mL of

NaOCl 2.25%, both solutions were activated

with an E11 #25 ultrasonic tip and a Vari-

os 370 ultrasound device (NSK, Shinagawa

Tokyo, Japan); finally 3 mL of sterile saline

solution were employed, a post-instrumen-

tation sample was taken at this point. Fi-

nally, the intracanal medication was placed

(Ca(OH)2) and the dental pulp chamber was

sealed with a temporary restoration (IRM,

Dentsply). On a second session (7 days after

session 1), each patient was anesthetized

with Mepivacaine HCl 2% + epinephrine

1:100000. A rubber dam was used and LC

Block Out was placed. The operative field

was disinfected, and the temporary resto-

ration was removed; then the intracanal

medication was eliminated using ultrasonic

tips; then the final irrigation protocol was

performed as follows, 2 mL of EDTA 17%,

followed by 2 mL of NaOCl 2.25%, both so-

lutions were activated by an E11 #25 ultra-

sonic tip and a Varios 370 ultrasound device

(NSK, Shinagawa Tokyo, Japan). Finally, 3

mL of sterile saline solution were used; the

operative field was disinfected as previously

described and the post-medication bacterial

sample was taken.

All the bacterial samples were taken us-

ing a sterile Capillary Tip (0.035mm) (Ul-

tradent®) connected to a 5 mL hypodermic

syringe. The sample was placed in Eppendorf

tubes with thioglycollate broth and incubat-

ed for 48 h in an anaerobic chamber (COY,

laboratory products, Incubator Model 2000

Great Lake, USA).

Once all the bacterial samples were col-

lected, the samples were incubated in an an-

aerobiosis chamber for 48 h, then samples

were processed for CFU counting, Gram

staining technique, and bacterial identifica-

tion by API-20 Strep /API-20A.

CBCT evaluation

A CBCT of the involved teeth was taken

before root canal treatment. The CBCT im-

ages were obtained by Kodak CS 9000 3D

tomography equipment. The image size was

established at 76 µm / 50 X 37 mm. Images

were examined using Kodak CS3D (version

3.2.12) software.

Of the 27 periapical lesions diagnosed,

ten were randomly selected and were mea-

sured using the PLM (Periapical Lesion Mea-

surement Index) previous to the root canal

treatment. Six months after non-surgical

endodontic treatment, a second CBCT was

taken to compare them. The bone volume

destruction was determined using axial, sag-

ittal, and coronal planes. The lesion’s width,

length, and depth were measured using the

axial, sagittal, and coronal planes. The im-

ages were evaluated by a calibrated external

observer using the Estrela’s index9: 0 = In-

tact periapical bone structures, 1 = Radiolu-

cency diameter 0.5-1 mm3, 2 = Radiolucency

diameter 1-2 mm3, 3 = Radiolucency Diam-

eter 2-4 mm3, 4 = Radiolucency diameter

4-8 mm3, Radiolucency diameter 8 mm3, +E

= Periapical cortical bone expansion, +D =

Destruction of the periapical cortical bone.

RESULTS

Microbial identification (API-20 Strep/

API-20A)

The biochemical method API identi-

fied 21 species of microorganisms in the

pre-instrumentation samples (Table 1), 11

species in the post-instrumentation samples

(Table 2), and 11 in the post-medication

samples (Table 3). The main microorgan-

isms identified were Actinomyces naeslundii

(16.66% pre-instrumentation/27.08% post-

Correlation between bacterial type and quantity and bone loss detected by CBCT 9

Vol. 64(1): 5 - 14, 2023

instrumentation/40% post-medication), and

Enterococcus faecalis (23.61% pre-instru-

mentation/29.16% post-instrumentation /

22.85% post-medication). Even when ade-

quate instrumentation, proper disinfection,

and use of intra-canal medication were car-

ried out, species were detected on samples

after non-surgical root canal treatment. This

confirmed the decrease of bacteria after

each therapeutic step procedure, but also

showed that the complete disinfection of the

root canal system is not possible.

For turbidity and CFU, descriptive sta-

tistic was performed (mean, mean error, stan-

dard deviation, minimum and maximum val-

ues) (Table 4) and compared between groups

(Table 5). The normality of the variables was

determined with the Shapiro-Wilk test. The

student’s T-test was used to compare groups.

A Pearson’s correlation coefficient was em-

ployed (95% confidence intervals).

According to the Gram stain, the bacte-

ria most identified in the present study were

Gram-positive.

CFU counting

According to the obtained results,

based on turbidity, there is a correlation co-

efficient of 0.598% between the initial size of

the lesion and the number of bacteria from

Table 1

Bacteria species found in pre-instrumentation

samples

1Actinomyces naeslundii 23.61

2Enterococcus faecalis 16.66

3Aerococcus viridans 8.33

4Streptococcus sanguis 6.94

5Fusobacterium nucleatum 6.94

6Clostridium spp 5.55

7Streptococcus oralis 4.16

8Aerococcus viridans 2 2.77

9Porphyromona asaccharolytica 2.77

10 Bacteroides spp 2.77

11 Actinomyces israelii 2.77

12 Streptococcus intermedius 2.77

13 Aerococcus viridans 2.77

14 Propionibacterium propionicum 1.38

15 Streptococcus pneumoniae 1.38

16 Streptococcus mitis 1.38

17 Clostridium perfringens 1.38

18 Aerococcus otitis 1.38

19 Aerococcus urinae 1.38

20 Gardnerela vaginalis 1.38

21 Prevotella oralis 1.38

Table 2

Species found in post-instrumentation samples

1Enterococcus faecalis 29.16

2Actinomyces naeslundii 27.08

3Porphyromona asaccharolytica 8.33

4PrevotelIa oralis 8.33

5Fusobacterium nucleatum 6.25

6Clostridium spp 6.25

7Streptococcus oralis 4.16

8Bacteroides spp 6.24

9Aerococcus viridans 2.08

10 Streptococcus pneumoniae 2.08

Table 3

Species found in post-medication samples

1Actinomyces naeslundii 40.00

2Enterococcus faecalis 22.85

3Aerococcus viridans 11.42

4Porphyromona asaccharolytica 5.71

5Fusobacterium nucleatum 2.85

6Bacteroides uniformis 2.85

7Clostridium cadaveris 2.85

8Clostridium perfringens 2.85

9Bacteroides stercoris 2.85

10 Streptococcus sanguis 2.85

11 Prevotella 2.85

10 Oliva Rodríguez et al.

Investigación Clínica 64(1): 2023

the pre-instrumentation sample, with a coef-

ficient of determination up to 35.7%; a cor-

relation coefficient of 0.486% and a determi-

nation coefficient of 23.6% between the size

of the initial lesion and the number of total

CFUs with statistically significant difference

(* p = ≤0.001).

The quantification of CFU counting

showed a bacterial decrease between the

pre-instrumentation, post-instrumentation,

and post-medication samples, with a sta-

tistically significant difference between all

groups (Table 5), which means that each

step procedure contributed to the control of

the odontogenic infection.

CBCT evaluation

Ten random PL were evaluated by CBCT

after six months of the endodontic treatment.

According to the data obtained, there was a de-

crease in the volume size of the PL (Table 6).

DISCUSSION

The present study contributes to the

knowledge about the amount and species of

microorganisms isolated and identified from

necrotic pulps, and determines a correlation

between the initial size of a PL and the num-

ber of bacteria. It also corroborates that the

root canal shaping, cleaning, and use of in-

tracanal medication decreased the amount

and species of bacteria identified, but do not

eliminate them.

According to the obtained data, the

bacteria most commonly identified from the

root canal system were Gram-positive facul-

tative anaerobes, corroborating previously

reported literature 6. It has been established

that the microorganisms in the biofilm are

exposed to very different environmental con-

ditions from those in planktonic form, and

many species can change their metabolism

depending on the surrounding physiologi-

cal and physicochemical conditions 10. Peri-

radicular dental biofilm is characterized by

microorganisms adhered to the cementum,

to the dentin, or both, in the apical portion

of the root, surrounded by an external poly-

saccharide matrix (biofilm) that limits the

access of defense molecules (antibodies and

Table 4

Mean comparison of groups

Sample Mean Mean

Error

Standard

Deviation

Minimum

Value

Maximum

Value

Turbidity Pre-Shaping & Cleaning 4.826 0.330 1.713 2.500 7.500

Post-Shaping & Cleaning 2.278 0.203 1.056 1.100 4.500

Post-Intracanal Medication 0.937 0.063 0.328 0.500 1.600

CFU Pre-Shaping & Cleaning 165.300 18.300 95.000 25.000 300.000

Post-Shaping & Cleaning 48.440 4.720 24.500 6.000 100.000

Post-Intracanal Medication 9.890 2.550 13.240 0.000 40.000

Table 5

Comparison of groups

Pre-Shaping & Cleaning

Post-Shaping & Cleaning

Pre-Shaping & Cleaning

Post-Intracanal Medication

Post-Shaping & Cleaning

Post-Intracanal Medication

Turbidity 0.001* 0.001* 0.001*

CFU 0.001* 0.001* 0.001*

*Statistical difference (P=≤0.001)

Correlation between bacterial type and quantity and bone loss detected by CBCT 11

Vol. 64(1): 5 - 14, 2023

complement) and phagocytic cells (macro-

phages and neutrophils) 6. The microorgan-

isms forming biofilms are more resistant to

antimicrobials (up to 1000 times less sus-

ceptibility to specific antimicrobials) and

the host immune defenses than their plank-

tonic counterparts 10.

The purpose of root canal treatment is

to debride and disinfect the root canal sys-

tem and to eradicate intracanal bacteria or

at least reduce them to a level below that

necessary to heal and prevent periapical dis-

eases or allow their resolution 11. However, in

some cases when the apical seal fails (apical

filtration), the pathology persists 12, due to

residual microorganisms 4, or extra-radicular

microorganisms 6, both with access to peri-

radicular tissues maintaining the patholo-

gy4. In primarily infected root canals, micro-

organisms were able to access and colonize

the pulpal tissue and impair its function 6.

The most common pathologic factors in the

alveolar bone derived from necrotic dental

pulp are PL 13. Their microbial profile con-

sists of 10-30 species per canal 6. According

to the data obtained in our study, at least

21 different species of microorganisms were

identified previously to the root canal disin-

fection. The species number identified post-

disinfection and post-medication decreased

to 11 species.

It has been reported that microorgan-

isms like Fusobacterium, Porphyromonas,

Prevotella, Parvimonas, Tannerella, Trepo-

nema, Dialister, Filifactor, Actinomyces,

Olsenella, and Pseudoramibacter predomi-

nated in the root canal system; also, some

facultative or microaerophilic streptococci

are commonly found in primary infections 6.

According to our data, the main microorgan-

isms identified were Actinomyces naeslundii,

Enterococcus faecalis, Aerococcus viridans,

Streptococcus sanguis, and Fusobacterium

nucleatum, corroborating previous reported

literature. Cardoso et al. 7 revealed a positive

correlation between root canal volume, de-

termined by CBCT analysis, and CFU count

found in primary endodontic infections with

apical periodontitis 7. It also showed that

the presence of selected bacteria species,

such as L. buccalis, P. intermedia, C. graci-

lis, C. gingivalis, and C. sputigena, as well as

Table 6

Comparison of periapical lesion before and after non-surgical root canal treatment

Sample Initial Lesion

Size

Initial PAI Lesion Size 6 Months

After Treatment

PAI 6 Months

After Treatment

Reduction

Percentage

1 8.20 mm35 6.96 mm34 15.12

2 13.80 mm3+D 7.90 mm34 42.75

3 7.00 mm34 4.59 mm34 34.42

4 5.92 mm33 3.19 mm33 46.11

5 23.00 mm3+D 7.92 mm34 65.56

6 8.96 mm3+E 4.34 mm34 51.56

7 7.15 mm34 4.60 mm34 35.00

8 25.74 mm3+E 11.13 mm3+D 56.75

9 50.31 mm3+E 22.99 mm3+E 54.30

10 5.60 mm34 3.04 mm33 45.71

Estrela’s Periapical Index (PAI): 0 = Intact periapical bone structures, 1 = Radiolucency diameter 0.5-1 mm3, 2

= Radiolucency diameter 1-2 mm3, 3 = Radiolucency Diameter 2-4 mm3, 4 = Radiolucency diameter 4-8 mm3,

Radiolucency diameter 8 mm3, +E = Periapical cortical bone expansion, +D = Destruction of the periapical

cortical bone.

12 Oliva Rodríguez et al.

Investigación Clínica 64(1): 2023

their interaction in the form of complexes,

was positively correlated with the presence

of clinical features. Cardoso et al. also re-

vealed that larger root canals hold higher

levels of culturable bacteria. Thus, the inter-

action of different virulent bacteria species

in complexes plays an important role in the

development of clinical features7. This data

is corroborated by the results reported in

this study, in which there is a relation be-

tween the number of bacteria and the pres-

ence of a PL. In a study performed in Taiwan

by Li-Wan Lee 14, it was found that the main

species of bacteria identified by matrix-

assisted laser desorption ionization-time

of flight mass spectrometry, were Porphy-

romonas endodontalis, Bacteroides fragilis,

Dialister invisus, Fusobacterium nucleatum

and Treponema denticola 14, the differences

of main species reported could be due to

the difference of population evaluated and

the laboratory techniques to isolate, cul-

ture and identify the microorganisms. One

of the main reported specie is E. faecalis, a

facultative gram-positive bacterium, capable

of surviving in an environment with scarce

availability of nutrients and minimal com-

mensality with other bacteria. It presents

different virulence and resistance mecha-

nisms, which hinder its eradication from

root canals 6.

Literature has reported that at a

6-month follow-up after the root canal treat-

ment, only half of the cases exhibit signs of

healing and that after a 12-month interval,

88% of these lesions exhibit signs of recovery.

In contrast, complete healing of the peri-api-

cal lesion might take up to four years 4. Our

study corroborates these findings since the

samples evaluated by CBCT 6 months after

the root canal treatment showed a size re-

duction of the PL. The control and resolu-

tion of the associated infection and healing

of PL depend on different factors, including

the amount and species of bacteria related

to the infection process and the capability of

the immune system to control the remain-

ing bacteria. Interactions of bacteria species

and their grouping into complexes make

endodontic infections even far more com-

plex for the immune system response, which

can lead to different clinical symptoms 7.

It has been reported that lesions ≤ 10

mm had an 80% of success rate while the

larger ones showed a success rate of 53% 12,

then the largest periapical lesions are associ-

ated with the worst prognosis 12. In our study,

it was possible to prove a directly proportion-

al relationship between the lesion size and

the amount and number of bacterial species.

Also, it has been established that the patho-

logic nature of the PL plays an essential role

in the clinical evolution of the periapical dis-

ease; a true periapical cyst is less likely to

heal after non-surgical root canal treatment

and might require peri-radicular surgery 4.

A definitive diagnosis of peri-radicular

cyst is reached only through histopathologic

evaluation 4,13 by serial cross-sectioning of the

lesion specimen 4. But nowadays, the CBCT

represents a non-invasive method for differ-

entiating periapical cysts and granulomas4.

Also, represents an ideal method to evaluate

the healing of a PL after root canal treat-

ment or surgical endodontic treatment, con-

sistent with the data reported in this study.

Nevertheless, according to the American

Association of Endodontists (AAE), CBCT

should only be used when the required imag-

ing question cannot be answered adequately

by lower-dose conventional radiography or

alternate imaging modalities 4.

The comprehension and understanding

of the microbial characteristics in the root

canal system play an essential role in the

treatment and resolution of periapical diseas-

es. This study determined that the amount

and species of microorganisms isolated from

necrotic pulps, established a correlation be-

tween the amount/species of microorganisms

and the size of periapical lesions, and showed

that the decrease of microorganisms through

the non-surgical root canal treatment con-

tributes to the healing of PL, corroborating

the importance of an adequate disinfection

protocol. It also established that the CBCT

Correlation between bacterial type and quantity and bone loss detected by CBCT 13

Vol. 64(1): 5 - 14, 2023

could be used as an objective method to

evaluate the evolution of a PL after root ca-

nal treatment. However, further studies are

needed to confirm the data reported.

Funding

Rangel Galván GY was the recipient of

a scholarship from the Consejo Nacional de

Ciencia y Tecnología (CONACYT), México.

This study was realized with funds of the Pro-

grama de Postgrado en Endodoncia, Facul-

tad de Estomatología, Universidad Autóno-

ma de San Luis Potosí, San Luis Potosí, SLP,

México.

Conflict of Interest

The authors declare not to present any

conflict of interest or competence with the

research work carried out.

Authors ORCID number

• Ricardo Oliva Rodríguez (ROR):

0000-0002-1797-1773

• Georgina Yaretzy Rangel Galván (GYRG):

0000-0003-3883-8258

• Ana María González Amaro (AMGA):

0000-0002-6375-9642

• Francisco Javier Gutiérrez Cantú

(FJGC): 0000-0001-7220-5791

• Abraham Israel Muñoz Ruiz (AIMR):

0000-0003-2522-3617

• José Obed García Cortés (JOGC):

0000-0002-7990-7312

• Jairo Mariel Cárdenas (JMC):

0000-0002-4733-7271

Authors Participation

• Conception and work design. ROR,

GYRG

• Collection/obtaining results. ROR,

GYRG, AMGA, AIMR

• Data analysis and interpretation.

ROR, GYRG, AMGA, FJGC

• Writing the manuscript. ROR, AIMR,

JMC, JOGC

• Critical revision of the manuscript.

ROR, AIMR, JOGC

• Approval of the final version. AIMR,

FJGC

• Statistical advice. JMC

• Ethical or administrative advice.

AMGA

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