Double Root and Root Canals in Right Mandibular Cusp Teeth and

Double Root Canals in Lateral Incisor Teeth: A Case Report

Jingli Zhu

, Tianzhu Song

, Lili Ding

and Miao Li

1,*

Hospital of Stomatology, Lanzhou University, Lanzhou, Gansu, 730000, China

Key Laboratory of Oral Diseases of Gansu Province, Northwest Minzu University, Lanzhou, Gansu, China

Keywords:

Mandibular Canines, Lateral Incisors, Double Root Canals, X-ray, CBCT, Microscope.

Abstract:

Root canal therapy is an important treatment for pulp disease and periapical disease. Root canal omission is

one of the main reasons for the failure of root canal therapy. Most of the mandibular apical and lateral incisors

are single root canals, and the number of double root canals is less. The case of double root canals of

mandibular canines is even less. This case will report the root canal treatment in which the right mandibular

canines and lateral incisors are double root canals at the same time.

1 INTRODUCTION

Root canal treatment is an important treatment for

endodontic and periapical diseases. Perfect root canal

preparation and root canal filling are the key factors

for successful root canal treatment. However, in the

clinic it is found that some patients still have

discomfort after root canal treatment, such as occlusal

pain and radicular pain, which are mostly caused by

root canal leakage due to root canal anatomical

variation (Siqueira, 2001). Routine imaging before

treatment is the primary factor for successful root

canal treatment, but the limited view of parallel

projection radiographs often makes it easy to miss

root canals routinely. Therefore, Therefore, CBCT

can be used in difficult cases or cases where root canal

omission is considered possible. The mandibular

cuspids have long roots in stomatognathic system and

have an occlusal guidance role (Magne, 2015). The

mandibular cuspids are mostly single root with single

root canal. The double root with double root canal

have been rare in recent year compared with single

root with single root canal. In contrast, more

mandibular lateral incisors with double root canals

have been reported. This is a case of double root with

double canals in right mandibular cusp teeth and

double root canals in lateral incisor teeth. Therefore,

it is important to discuss the root canals anatomical

morphology of the mandibular cuspids and lateral

Corresponding author

incisors and clinical considerations for the success of

root canal treatment and the preservation of the

treated tooth.

2 CASE INFORMATION

The patient, a 45-year-old female, was treated in an

outside hospital for her lower right tooth ten years

ago. The original restoration was fractured three days

ago. She was then treated in our prosthodontics

department, and is now referred to our department for

root canal treatment.. The examination found 42 was

residual roots, with the edge flush with the gingiva or

1-2mm above the gingiva. 43 was residual crowns

with distal residual tooth tissue and exposed root

canal orifice which have no probing pain;42 and 43

teeth without loosening and periodontal pocket were

not suitable for percussion and was slightly painful

for palpation, and no obvious abnormality was found

in buccal mucosa 42 and 43 cases were diagnosed as

chronic apicitis and tooth tissue defect. The treatment

plan was post core crown repair after 42 and 43 root

canal treatment. The treatment process was that 42

and 43 teeth cleared rotten matter under the

microscope with rubber barrier.42 probed two root

canals and 43 one root canal. After root canal length

measurement, M3 cleared root canal with ultrasonic

swing washing and 1% sodium hypochlorite. Before

138

Zhu, J., Song, T., Ding, L. and Li, M.

Double Root and Root Canals in Right Mandibular Cusp Teeth and Double Root Canals in Lateral Incisor Teeth: A Case Report.

DOI: 10.5220/0012014900003633

In Proceedings of the 4th International Conference on Biotechnology and Biomedicine (ICBB 2022), pages 138-141

ISBN: 978-989-758-637-8

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

glass ion temporary sealing ,42and 43 was dried with

paper tip suction and then used calcium hydroxide in

root canal. The root canal filling was prepared at the

second visit, but it was found that glue tips of 42 tooth

could reach the root canal length in the buccal root

canal, while the lingual could not reach the root canal

length completely. After X-ray, it was found that 42

tooth test tips were suitable, while 43 were double

roots and there were root canal omissions. Then 43

was rediscovered the lingual root canal under the

microscope and was cleaned .42 and 43 teeth were

filled with hot gum after ultrasonic swing washing.

X-ray showed that the root was filled in place and the

tooth was sealed with glass ion. It was suggested that

the prosthetic department should carry out further

prosthetic treatment after one week of observation.

(Fig.1-4).

Figure 1: First root canal test tip.

Figure 2: Second root canal test tip.

Figure 3: Root filling.

Figure 4: omitted root canals Under microscope.

3 DISCUSSION

3.1 Root Canal Typing

Root canal therapy will greatly reduce the success

rate of root canal therapy if root canal omission

occurs. Mastering the anatomical morphology of root

canal will greatly reduce the occurrence of root canal

omission. Scholars have carried out a series of

research and experiments in recent years. Weine et al.

divided the whole path change from dental pulp

cavity to apical foramen into four types by truncation

and radiology methods. Type I: one root canal from

pulp cavity to apical foramen (type 1-1); Type II: two

canals left the medullary cavity and fused into one

canal before reaching the apical foramen (type 2-1);

Type III: two independent canals from medullary

cavity to apical foramen (type 2-2); Type IV: one

canal leaves the medullary cavity and is divided into

two canals with two apical foramen (type 1-2)

(Weine, 1969). Vertucci et al. studied the transparent

specimens of the second premolar by using the

staining method and found that the complexity of root

canal morphology is far more than that of

weineclassification. He proposed eight types: 1-1, 2-

1, 1-2-1, 2-2, 1-2-1-2, 3-3 (Vertucci, 1974). This

method includes most root canal morphology in

clinic. Some researchers have shown that the peak

incidence of multiple root canals of mandibular

canines is concentrated over the age of 30, and shows

a downward trend after the age of 60. This may be

related to different ethnic groups, regional

populations or sample sizes, as well as root canal

cross-sectional morphology and secondary dentin

deposition (Fig. 5). Therefore, for middle-aged and

elderly patients, in addition to mastering the number

of root canals per tooth, we should also consider the

impact of secondary dentin deposition on the

morphology and number of root canals with age.

Especially for single root canal flat root anterior teeth,

it is possible to form isthmus formed by secondary

dentin in the middle of root canal. The occurrence of

Double Root and Root Canals in Right Mandibular Cusp Teeth and Double Root Canals in Lateral Incisor Teeth: A Case Report

139

this situation may cause the clinician to lose the root

canal during the root canal preparation or fail to

complete the root canal cleaning due to the

appearance of steps in the root canal. The 43 teeth of

the cases were vertucciiv (2-2) root canals. The

mandibular lateral incisors root is flat with mostly

single root canal, but also double root canal mostly

distributed in the labial and lingual direction. At

present, there are many cases of mandibular lateral

incisors with double root canals. It is generally

believed that about 10% of mandibular lateral incisors

have double root canals. Laws et al. Respectively

used X-ray films to study the samples inside and

outside the mouth. It was found that the incidence of

double root canals of mandibular lateral incisors was

more than 40%. VertucciⅡ (2-1) root canal accounted

for 5.33%. The double root canals of the central

incisor in this case were vertucciⅡ (2-1).

3.2 Application of CBCT

In order to avoid root canal omission, it is necessary

to master the anatomical morphology of root canal. In

addition, the imaging examination before individual

tube treatment is also particularly important.

Conventional parallel projection X-ray film is one of

the conventional imaging examination methods

before the treatment of dental periapical disease. It

can show the shape and length of root canal, and

roughly evaluate whether there is root canal

calcification. However, the specific number and

shape of root canal and tooth root are often unclear

because the X-ray film is the two-dimensional image.

It will be inaccurate to judge whether there is root

canal omission completely based on X-ray

examination (Eisner, 1998). With the development of

science and technology, the emergence of CBCT

makes this problem simple (Kaasalainen, 2021).

Three-dimensional imaging of CBCT can accurately

judge the number, shape and variation of root canals.

Therefore, CBCT examination of difficult root canals

is very important. However, CBCT is not routinely

used in root canal therapy due to its high cost. In this

case, the patient did not take CBCT at the initial

diagnosis due to economic reasons. When CBCT

cannot be taken, we should also fully interpret the X-

ray information. If the root canal image suddenly

becomes thinner or disappears, there may be root

canal branches at this location, which needs to be paid

attention to in actual operation.

secondary dentin formation in root canal leads to the evolution of single root canal into multiple root canals with the increase

of age; The gray area is the root canal, and the white area protruding into the root canal is secondary dentin

Figure 5. Single root canal evolving into multiple root canals.

3.3 Intraoral Manipulation

3.3.1 Oral Operation

In clinical practice, because the root of the tongue is

more inclined to the lingual side, the root canal orifice

is often blocked by the top of the pulp chamber or the

dentin collar, which accounts for the main reason for

the root canal omission of the lower anterior teeth

(Sener, 2009). 43 was generally considered as a single

tube at the initial diagnosis, but after changing the X-

ray projection angle in the test tip film, it can be

clearly seen that 43 has two tubes and one tube is

missing. Later, when looking for the missing root

canal, it was found that 43 the missing root canal on

the lingual side was found after uncovering the

medullary chamber roof on the lingual side. In

practice, it should also be noted that when the root

canal deviates to one side, it should carefully look for

another root canal on the opposite side. If there is

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calcification blocking the root canal orifice, it should

carefully remove the calcification with ultrasonic

instruments under the microscope to look for another

root canal.

3.4 Application of Microscope

The application of microscope is of great significance

for root canal therapy. The use of microscope in root

canal therapy can directly look into the medullary

cavity and avoid root canal omission to a greater

extent (Bonsor, 2015). For mandibular anterior teeth,

most of them are single root canals and it is difficult

to find multiple root canals. The 42 teethin this case

was single root and there was no obvious double root

image on the X-ray film.Butthen two root orifices

were obviously visible at the enamel cementum

boundary of the medullary cavity under the

microscope during the treatment. The42 teeth length

measurement and root canal preparation were carried

out, but the buccal gum tip could reach the root canal

length during the tip test while the lingual gum tip did

not fully reach the root canal length about 5mm away

from the root tip. Therefore, it is judged that 42 is the

2-1 type root canal. The results showed that the

detection rate of double root canals increased from

16.08% to 27.27% before and after microscope

. The

microscope can enlarge the operation area and

provide a clear field of vision for the operator. The

removal of calcified substances under the

microscope can effectively avoid the occurrence of

pulp chamber floor penetration and root canal

lateral penetration caused by unclear field of

vision, so as to improve the detection rate of root

canal and the success rate of root canal treatment.

4 CONCLUSION

This case suggests that we should be alert to the

existence of root canal variation and fully understand

the anatomical morphology of root canal of each

tooth before root canal treatment. In root canal

therapy, X-ray multi angle photography or CBCT

photography should be carried out to find the variant

root canal in time. Before root canal preparation, the

pulp chamber top should be uncovered and combined

with microscope to prevent root canal omission and

improve the success rate of root canal treatment.

ACKNOWLEDGEMENTS

This work was supported by Research Support Fund

of School of Stomatology Lanzhou University (No.

lzukqky-2020-t05).

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