Summary of medical doctoral thesis: The impact of operating microscope on the outcome of endodontic treatment in first maxillary molar

Describe the clinical and radiological features of the upper first molar indicated for endodontic treatment; assessing the effectiveness of microscope application in the treatment of upper first molar; evaluation of the results of the upper first molar’s endodontic treatment.

HANOI MEDICAL UNIVERSITY

BUI THI THANH TAM

THE IMPACT OF OPERATING MICROSCOPE ON THE OUTCOME OF ENDODONTIC TREATMENT IN FIRST

HANOI MEDICAL UNIVERSITY

PROBLEM STATEMENT

With the development of science and technology, microscopes have also been applied in dentistry in many countries around the world Many scientific works have shown the outstanding advantages

of microscopes applied in dentistry The use of endodontic microscopes helps to identify symptoms, diagnose the disease correctly, and detect the root canal more easily With the remarkable advantages of the microscope in terms of magnification and focus, the microscope really opens a new era for dentsitry in general and Endodontic in particular In Vietnam, the research and application of microscopy in endodontic treatment is still limited In order to evaluate the applicability of microscopes in dental treatment of endodontics, we conducted the study "Study of microscopy application in root canal treatment of upper first molar" with the following objectives:

1 Describe the clinical and radiological features of the upper first molar indicated for endodontic treatment

2 Assessing the effectiveness of microscope application in the treatment of upper first molar

3 Evaluation of the results of the upper first molar’s endodontic treatment

The need of the study

Endodontic diseases always make up a high proportion in dental diseases Endodontic treatment is an important area of restorative dentistry to restore function and aesthetics to diseased teeth The upper first molar is one of the earliest erupted teeth and has the most endodontic treatment, but the rate of failure of endodontic treatment

is the highest among the molar teeth Many studies show that the presence of MB2, as well as unsatisfactory cleaning of the pulp chamber, is the main cause of treatment failure Therefore, the application of technical advances such as dental microscopes to detect root canals, wall crevices, pulp chambers, granules and calcified blocks is extremely necessary to support the dentist in detect, clean, shape the canal, and pulp chamber treatment

New contributions of the study

- This is a research project following the new trend of microscope application in the accurate diagnosis and examination of fissures before and during treatment, the discovery of calcified particles and calcification chamber, and management of complications when encountered in the treatment of upper first molar

- The thesis specifically evaluates the efficiency of using a microscope to detect the orifice of the root canal, of which the most effective is to detect the MB2 is much higher than naked eye

- The results of the study are monitored up to 24 months after treatment, which is long enough to generalize the results, making recommendations in the application of microscopes in endodontic treatment

Layout of the thesis

The thesis has 143 pages, including sections: problem statement (2 pages), introduction (44 pages), subjects and research methods (18 pages), results (47 pages), discussion (29 pages), conclusion (2 pages), Suggestion (1 pages), The thesis has 49 tables, 47 pictures, 8 charts, 1 diagram 131 references including Vietnamese and English documents

CHAPTER 1: INTRODUCTION 1.1 Anatomy of the upper first molar root canal system

The upper first molar is the earliest permanent tooth, so it is the first to decay Upper first molar has three root: two buccal root (MB and DB) and one platal root Each root corresponds to 1 root canal, sometimes 2 canals, usually found in the proximal canal

1.1.1 Outer anatomy

Viewed from the occlusal surface: The contour is usually diamond shape Three large cusps form a typical pattern for maxillary molar teeth, which are linked together into a triangle These are important anatomical landmarks applied when opening pulp for endodontic treatment of the upper fist molar teeth

On the external outer view: the pulp chamber is wider, the horn of the pulp is usually protruding Usually has 3 legs with 3 root canals The proximal canal is shorter than the inner canal, the proximal canal

is usually very wide and in most cases there is an additional root canal

On a view across the pulp chamber in the neck of the tooth: the shape of the pulp chamber in the neck of the tooth is shaped like a parallelogram

* The pulp chamber ceiling is the upper limit of the pulp chamber, usually far from the floor in young people and is lowered in the elderly due to the development of dentine as well as mechanical and chemical stimuli

* The pulp floor is the lower limit of the pulp chamber, on the floor

of the pulp chamber has an opening of the root canal However, the calcification of the pulp chamber makes it difficult for endodontic treatment, the orifices can be obscured making it more difficult to access the pulp chamber and the risk of instrument fracture This phenomenon is quite common in root canal

1.1.2.2 Root canal system

The root canal system starts from the orifice of the root canal at the floor of the pulp chamber and ends at the end apex There are 3 or

4 root canals forming triangles with acute distal angle

The root canal system in the upper first molar is analyzed by the Weine classification system, most teeth have 3 roots, each root usually has 1 root canal, the additional root canal is MB (79.2%) and

DB (1.65%)

1.1.3 The study of internal anatomy of teeth

Laboratory or clinical studies to describe internal anatomy include many different types of methods

1.1.4 Some landmarks open marrow anatomy application

The entry point to the pulp chamber of upper first molar starts from 1-2mm from the MB cusp towards the central groove, using a round drill or Endo access to open into the pulp chamber According

to Hess, the opening is a trapezoid shaped narrower than the pulp floor In the case of not seeing the orifice, open the chamber further and follow the mesial diagonal

1.2 Pathology of dental pulpal and periapical disease

Causes: bacterial infection, physical factors

Classification of the pathology and diagnosis is based on clinical and paraclinical symptoms according to the American Endodontic Association recommendations for use in 2008

Diagnosis of pulpal disease: Classification of pulp pathology is mainly based on clinical signs, subclinical and physical symptoms Periapical disease: include acute, subacute or chronic lesions Injury area usually refers to lesions in the ligament and bone region around the apical area

1.3 Endodontic treatments: Conservative treatment (Pulp capping

Partial pulpotomy), root canal treatment

1.4 Some causes of failure in endodontic treatment: Opening

wrong path, broken instrument, obturation over apex

1.5 Microscope application in endodontic treatment and treatment results

1.5.1 Introducing the microscope

A microscope is a device for viewing very small objects that are invisible to the naked eye The visibility of a microscope is determined by its resolution

Advantages of magnifying devices:

The three main advantages identified are related to the use of endodontic amplification devices, that is, (1) a clearer working field, (2) improved working posture and (3) increased persuasion ability Disadvantages of microscopes

Some of the reported drawbacks are the time it takes to get used to new equipment, the cost of magnification equipment and related accessories, the need for additional infection control, and possibly injury due to the sharp instruments

1.5.2 Some research results using microscopy in endodontic treatment

Several studies have shown that it significantly increases the ability of dentist to locate and access the root canal Therefore make the results of treatment increase

CHAPTER 2: MATERIALS AND METHODS

2.1 Materials

Maxillary first molars which needed endodontic treatment, were treated at Department of Endodontics, National Hospital of Odonto-Stomatology from January 2013 to April 2019

 Inclusion criteria

- Maxillary first molar needed nonsurgical endodontic treatment

- Restorative management is available after root canal treatment

2.2.1 Method: thepary study with intervention

2.2.2 Sample size and selection

 Sample size

n: minimum sample size

: α = 0,05 = 1,96

p: Prevalance of success endodontic treatment (90%)

After calculating, n=97 In fact, we treated 105 maxillary first molars Sample selection: satisfactory All the patients with inclusion criteria were screening, explained and invited to participate We collect until adequate volume

2.3 Procedures Information collected

Examine, pulp testing (with microscope)

X-ray: periapical view Diagnosis, etiology Anesthesia

Rubber dam Pulp access

Identify orifice

Irrigation and shaping

Obturation

Restoration

Follow - up

2.4 Diagnosis and treatment

2.4.1 Symptoms and Xray

+ Soft tissue: red, swelling, painful when press, sinus tract

+ Hard tissue: caries dectection, cracked teeth (by eyes and microscope)

- X-ray: periapical view

- Diagnosis: pulp diseases, periapical diseases

- Protocol: base on the protocol that AAE recommend in 2008

2.4.2 Treatment

Treatment procedure

- Anesthesia: local (vital pulp)

- Wall build –up (if needed)

- Place rubber dam

- Access

- Observe pulp chamber: calcification or not, cracked line (by eyes and microscope)

- Detection and shaping (2 phases)

Phase 1: Identify orifice by endodontic explorer and eyes Take photos of pulp floor

Phase 2: Identify orifice by endodontic explorer and microscope After finding the forth or fifth orifice, continue to:

- Open

- Identify working length

- Shaping by rotary files Protaper

- Cold lateral compaction and warm vertical compaction

- Master cone fit radiograph

- Restoration

- Follow up

2.4.2.3 Results

* After obturation on Xray

- Bad condensed

Underextension

>2mm or or overexthension

≤ >1mm

* Post-op afer 1 week

Soft tissue No swelling No swelling Red, swelling, pain

when press Percussion No pain Mild pain Sharp pain

* Post-op after 3-6 months, 12 months and 2 years: Examine, Xray

-No pain, no swelling

- Percussion: mild pain

Periapical lesion: no change

Bad

-Bite: pain

-pain, swelling

- Percussion: pain

Periapical lesion: bigger

2.6 Errors and error corrections

2.6.1 Errors

2.6.2 Error corrections

2.7 Data processing: STATA 15.1 softwar

2.8 Ethical aspect of research

* Ethics in research

The research was allowed by the Council of PhD, School of Odonto-stomatolgy, Hanoi Medical University It is also accepted by the Director of National Hospital of Odonto-Stomatology All the patients included was explained clearly about the purpose, meaning, benefit and risk of this research All the information and data collected is protected and used only for this research

CHAPTER 3: RESULTS 3.1 Clinical and X-ray characteristics of the maxillary first molar before treatment

Table 3.1 Distribution of study population by age and gender

Table 3.2 Distribution of reasons for visit by age

Total 17 (100) 41 (100) 47 (100) 105 (100) The reason patients coming to visit due to pain was the highest proportion (74.3%), due to swelling and pain was 23.8% and due to other reasons was only 1.9% The difference was statistically significant with p <0.05

Table 3.5 Distribution of causes by age group

Total 17 (100) 41 (100) 47 (100) 105 (100)

The tooth crack increases with age; in the group <30 is 11.8%, the age group from 30 - 44 is 51.2%, in the group of > 44 is 70.2% In contrast, the incidence of tooth decay decreases with age This difference is statistically significant with p <0.05

Table 3.7 Detection of tooth crack by visual examination and

microscope by age group

Total 17 (100) 41 (100) 47 (100) 105 (100)

- The highest sign cracked tooth can be found in the age group>

44 is 57.4%, in the group of 30 - 44 is 51.2%, in the group <30 years

of age there is very little 5.9% when examine without microscope The difference was statistically significant with p <0.05

- When examined under the microscope, the percentage of tooth cracked increased significantly in the group> 44 years old from 57.4% to 85.1%; 30 -44 age group increased from 51.2% to 70.7%; The group

<30 years old increased from 5.9% to 17.6% The difference was statistically significant with p <0.05

- By visual examination, 46.7% of teeth with cracked lines were discovered, when examination by microscope the percentage of cracked lines increased significantly to 68.6% The difference was statistically significant with p <0.05

Table 3.9 Images of the pulp chamber and the periapical X-ray by

age group

Age Xray

<30 (n=17)

30 – 44 (n=41)

>44 (n=47)

Total (n=105)

Pulp

chamber

Without calcification 16(94,1) 21 (51,2) 7 (14,9) 44 (41,9) Calcified 1 (5,9) 20 (47,8) 40 (85,1) 61 (58,1)

Periapical Normal 16(94,1) 31 (75,6) 33 (70,2) 80 (76,2)

Lesion 1 (5,9) 10 (24,4) 14 (29,8) 25 (23,8)

- On the x-ray image, the proportion of calcified chamber was 51.8%, increased significantly with the 3 increasing age groups, respectively, the age group <30 years 5.9%, age group 30 - 44 years old 47.8% and the group >44 years old is 85.1% The difference was statistically significant with p <0.05

- The rate of periapical lesion is 23.8%, the highest prevalence was in the age group of> 44 years and 29.8%, then to the group of 30 -44 years old with 24.4% and the lowest was the group <30 years with 5,9%

3.2 The effectiveness of microscope application in the treatment

of the maxillary first molar:

Bảng 3.12 Detect cracks in the pulp chamber through the naked

eye examination and microscopy by age group

>44 n=47

(94,1)

29 (70,7) 3 3(70,2)

78 (74,3)

Microscope

Yes 2 (11,8) 22

(53,6) 33 (70,2)

57 (54,3)

(88,2)

19 (46,3) 14(29,8)

48 (45,7)

- Proportion of crevices in the tooth pulp chamber increases with age when observed with the naked eye and a microscope:> 44 years of age is

70.2%; group of 30-44 years old is 53.6%; The group <30 years old is 11.8% This difference is statistically significant with p <0.01

- The rate of detecting fissure in the wall of medullary chamber by microscopy in the corresponding groups is: group <30 years old eye

is 5.9%, KHV is 11.8%, group 30-44 years old is usually 29 , 3% and KHV is 53.6%, the group> 44 years old eyes is 29.8% and KHV is 70.2% This difference is statistically significant with p <0.01

Table 3.15 The rate of detecting discrete calcified particles with the

naked eye and microscope by age group

Observed results show that the rate of discrete calcified particles tends to decrease with age when observed with the naked eye, especially when observed with a microscope The results are 35.3% (age <30), 34.1% (age 30 - 44), and 20.5% in patients aged above 44 years The difference was statistically significant with p <0.05

Thus, in people aged above 44 years, the proportion of discrete calcified particles is the lowest The difference was statistically significant with p <0.05

Table 3.19 The rate of detecting calcified masses with the naked eye and microscope in pulp chamber by age group

Age group

Calcified masses

<30 (n=17)(%)

30 – 44 (n=41)(%)

>44 (n=47)(%)

Tổng số (n=105)(%)

Naked eye yes 2 (11,8) 20(48,8) 29 (61,7) 51 (48,6)