ĐẶT VẤN ĐỀ Răng hàm lớn thứ nhất, thứ hai hàm trên là nhóm răng có hệ thống ống tủy phức tạp, tỷ lệ phải điều trị t ủy nhiều nhất trên cung hàm. Khảo sát đầy đủ hệ thống ống tủy, hàn kín theo ba chiều là các yếu tố quan trọng giúp điều trị thành công. Phương pháp chụp cắt lớp vi tính chùm tia hình nón- Cone Beam Computed Tomography (CBCT) cho hình ảnh 3 chiều của răng và tổ chức xung quanh, khắc phục nhược điểm của phim quanh chóp như chồng lẫn hình ảnh, khó đánh giá chính xác hệ thống ống tủy đặc biệt với các răng hàm phía sau, có nhiều chân như răng hàm lớn thứ nhất, thứ hai hàm trên. Kĩ thuật hàn Thermafil cho kết quả hàn kín khít tốt với mật độ khối hàn đậm đặc, khắc phục khó khăn khi hàn các ống tủy khó thao tác với cây lèn như ở nhóm răng hàm lớn hàm trên. Kết hợp ưu điểm của phim CBCT và kĩ thuật hàn Thermafil khi điều trị tủy nhóm răng hàm lớn thứ nhất, thứ hai hàm trên với hệ thống ống tủy phức tạp nhằm cải thiện chất lượng và đánh giá kết quả sau điều trị tủy. Tại Việt Nam, chưa có nghiên cứu ứng dụng phim CBCT trên lâm sàng điều trị tủy nhóm răng này, vì vậy chúng tôi thực hiện đề tài: “Nghiên cứu điều trị tủy răng hàm lớn thứ nhất, thứ hai hàm trên bằng kỹ thuật Thermafil có sử dụng phim cắt lớp vi tính chùm tia hình nón” với mục tiêu sau: 1. Mô tả đặc điểm hình thái hệ thống ống tủy răng hàm lớn thứ nhất, thứ hai hàm trên dựa trên hình ảnh phim cắt lớp vi tính chùm tia hình nón. 2. Đánh giá kết quả điều trị tủy răng hàm lớn thứ nhất, thứ hai hàm trên bằng kĩ thuật Thermafil dựa trên hình ảnh phim cắt lớp vi tính chùm tia hình nón.
MINISTRY OF EDUCATION AND TRAINING MINISTRY OF NATIONA L DEFENSE 108 INSTITUTE OF CLINICAL MEDICAL AND PHARMACEUTICAL SCIENCES TRAN THI LAN ANH RESEARCH ON ROOT CANAL TREATMENT OF FIRST AND SECOND MAXILLARY MOLARS BY THERMAFIL TECHNIQUE USING CONE BEAM COMPUTED TOMOGRAPHY Speciality: Odonto Stomatology Code: 62720601 SUMMARY OF DOCTORAL THESIS Hanoi – 2020 Q UESTIO N The first and second maxillary molars havethe most complex root canal systemsin the arch Thecomprehensive investigation of the root canal system and three-dimensional obturating are important factors for successful treatment Cone Beam Computed T omography (CBCT ) which create 3-dimensional images of teeth and the surrounding structures has advantages, overcoming the disadvantages of the periapicalfilms, difficult to identify of canal system of molars with many root teeth as first, second maxillary teeth Thermafilobturation technique is ideally in the sealing with dense obturation, overcoming difficulties when obturation canals that are difficult to manipulate with the pitch as in the first, second upper jaw group Combining advantages of CBCT film and Thermafil technique is guarantee for the success of the complex canal structures of the first, second maxillary teeth to improve the quality of treatment and post-treatment evaluation marrow The effect of this combination has not been investigated in Vietnam Hence, we conducted this study t itled "Research on the root canal tre atment of the first and second maxillary molars by Thermafilte chnique uses Cone Beam Compute d Tomography”with the following object ives: Describe the morphological characteristics of the first and second maxillary molars root canal system based on Cone Beam Computed Tomography Evaluation of the results of first and second maxillary molars root canal treatment using Thermafil technique based on Cone Beam Computed Tomography The urgency of the thesis:Saving a decaying tooth is always a t op priority in our clinical practice For the first and second maxillary molars, the root canal system can be missed on the periapical film due to overlapping images Application of technological advances such as CBCT and Thermafilobturation technique improves t he quality of treatment and accurately evaluate the results of root canal treatment Ne w contributions of the the sis: T he results of this study showed the important of CBCT in diagnosis and determination of root canal system after root canal treatment Moreover, thermafilobturation technique has an excellent characteristic and obturates the canal and lateral and accessory canals when compare to other conventional techniques The thesis has 122 pages including sections: problem statement (2 pages), overview (33 pages), subject s and Methodology (25 pages), results (20 pages), Comment (39 pages), conclusion (2 pages), recommendations (1 page) The thesis has 58 tables, 57 pictures, 111 references including Vietnamese and English documents Chapte r O VERVIEW 1.1 Characte ristics of root canal system 1.1.2 Anatomical characte ristics of the first and second maxillary molars 1.1.2.1 First maxillary molars: Most First maxillary molars teeth have three separate teeth The mesiobuccal root is the most complicated root on the arch, with a wide cross section in the buccolingual dimension, or root canal The distobuccal root and palatal root mainly has canal 1.1.2.2 Second maxillary molars: Anatomical structure of second maxillary molars is similar t o First maxillary molars but t he crowns are not square and big.Their roots are relatively close together or root fusion can be seen They generally are shorter than the roots of the first molar and not as curved Four canals are less likely to be present in the second maxillary molar than in the first maxillary molars The ratio of Second mesiobuccal canal is not as high as First maxillary molars 1.2 Pulpal disease 1.2.1 Diagnosis of pulpal disease: The diagnosis is based on all necessary information including medical and dental history, funct ional and physical symptoms, X-ray, assessment of periodontal status and clinical examination.According to the American Associat ion of Endodontic (2008), the terms that diagnose pulpal disease in clinical include: Reversible Pulpitis (acute, chronic), irreversible Pulpitis (acute, chronic), Pulp Necrosis (no infection, infection), Previously Treated, Previously Initiated T herapy Clinical terms for Periapical disease diagnosis: Symptomatic Apical Periodontitis, Asymptomatic Apical Periodontitis, Acute Apical Abscess, Chronic Apical Abscess 1.2.2 Root canal tre atment 1.2.2.1 Determine and maintain working length, working width during cleaning, shaping and obturatingroot canal systems Working length: According to Johnson W et al., There are more than 50% of root canals without apical constriction, especially with apical disease, so t hat there is uniformity in the treatment limit of the apical foramen, terminatingthe preparation is usually chosen t o be 0.5 to mm short of the radiographic apex Working width - size and root canal taper at the end of the cleaning and shapingroot canal: due to t he initial size of the root canal, the cleaning and shaping and obturating technique root canal system 1.2.2.2 Cleaning and shaping root canal system Cleaning root canal system: the common option is a combination of sodium hypochlorite and ethylene diamine tetra acetic acid (EDT A) To clean the complete root canal system, especially at the apical third of the root canal, the lateral and auxiliary canal, or the Cshaped canal, endodontic ultrasound systems are used widely Calcium hydroxide is widely used place in root canal between appointments due to its ability to dissolve organic tissue, kill bacteria, detoxify and act as a slow-release substance due to its low solubility in water Shaping root canal system: the most popular shaping method today is the use of a rotating NiT ifile 1.2.2.3 Obturatingroot canal system: The obturation is aim to seal the entire root canal system in three dimensional to prevent the invasion of microorganisms from t he mouth or the area around the teeth into the root canal system Thermafil technique: A technique developed by Johnson W.B Thermafil was commercialized in the early 1990s, with Gutt aPercha (GP) α phase covering hard plastic core but still ensuring flexibility Α phase GP is warmed by a oven, put into root canal with the core in the center to help compress the soft GP flowing into the root canalsystem Gencoglu N et al assessed that the number of lateral root canal found that more lateral canal sealed with T hermafil, followed by System B / Obtura, Horizontal, Microseal, Quick-Fill, Soft core Samadi F et al (2014) found that root canal Thermafil technique produces a higher percentage of GP in root canal, creating a more homogeneous obturat ing block than warm GP compacting or cold GP horizontal compaction at apical third of root s According to Zogheib C et al., Thermafil technique give adequate obturationwithoutvoids and gaps in the obturatedroot canals 1.2.3 Assess the re sults of root canal treatment 1.2.3.1 Asse ssment of root canal obturating quality: In addition to clinical evaluation, the most necessary factor is to evaluate t he root canal obturating results in terms of length, shape and density Root canal obturating must seal into the root canal walls, the obturatingmaterial must be tightly compressed, closed and sealed in the shape of root canals into a homogeneous GP block 1.2.3.2 Follow u p afte r tre atment: to maintain healthy or monitor wound healing of apical area Success aft er t he root canal treatment is that there are no clinical and radiographs signs of periapical lesions 1.3 Dental radiography 1.3.1 PeriapicalRadiographs:The film is the most popular filmin the dental treatment and a useful t ool to make a diagnosis, planning, and evaluate the outcome following endodontic treatment it has low cost; low radiation compares to the other x-ray techniques However, it can cause distortion, overlap and miss images The images can only be seen in the mesial and distal direction 1.3.2 Cone Beam Computed Tomography (CBCT):The significant of advanced diagnosis tool such as CBCT over the traditional methods has been proven T his advance technique assists dental practitioner to identify root morphology, number of canals and other factors which can affect the final outcome of the treatment Images can be displayed and investigated in the three orthogonal planes, axial, sagittal, and coronal simultaneously In CBCT film, sagittal, and coronal slices are made all along the length of the root, axialslices are perpendicular to the axis of the root with the thickness of the slice usually 1mm The axial section shows the shape, the number of the root, the root canal, which is the most advantage of CBCT compared to periapical films Coronal slices shows the root canal morphology, the root canal curvature in the bucal langualdirection Sagitalslices shows root canal images in mesial distal direction.In the root canal treatment, the use of small field CBCT images to show a few teeth and the surrounding structure is suitable for minimizing radiation dose while good image quality, specific distinction structures such as enamel, dentin, root cavity, alveolar bone and cortical bone, tooth anatomical structure, root canal system characteristics, pathological image of root, etc According to Zheng et al, Zhang R and cs, CBCT effective in studying the external and internal morphology of the teeth, helping to optimize the results of root canal treatment A study by Abubara et al (2012) showed that CBCT determined the Second mesiobuccal canal number compared to the periapical film, clearly showing that untreated root canals.Research by many authors such as Yoshioka T et al., Anita A et al., Estrela et al., Venskutonis T et al., showed that CBCT film was more sensitive, identifying lesions accurately than the periapical film, the difference is more pronounced in the molars According to Estrela et al, CBCT film accurately assesses the curvature of the canals, helping to minimize errors and fractures during pulp treatment Chapte r SUBJECTS AND METHO DS 2.1 Study subje cts: First and second maxillary molars are indicated for root canal treatment of patients at the Hitech Department, Nat ional Hospital of Odonto-Stomatology of Hanoi, during 20162019, teeth were eligible to be selected for research samples and patients voluntarily participated 2.1.1 Inclusion criteria: The patients is 18-60 years old and hasFirst and second maxillary molars are indicated for non-surgical root canal treatment T eeth are diagnosed in of the following diseases: Irreversible pulpitis, Pulp necrosis, Acute apical periodontitis, Chronic apical periodontitis 2.1.2 Exclusion criteria: The patients has systemic diseases Patients cannot cooperate when performing treatment techniques and x-rays imature, periodontitis, internal and external teeth 2.3 Research Methods 2.3.1 Study design: Non-controlled clinical intervention study 2.3.2 Method of sample size determination - Apply the formula for calculating the sample size for a noncontrolled clinical intervention study: n= ( ) / n: minimum sample size p: success rat e aft er treatment, estimated at 90% (according to research results of Peng L et al (2002) a: t he level of statistical significance, a here is determined to be 0.05 with 95% confidence level a = 0.05 → / = 1,962 d: is t he desired accuracy, taking d = 8% From the above formula, we calculate the sample size as follows: 0,9 x 0,1 n = 1,96 = 54 0,082 We chose the sample size for the study of 55 teeth 2.5 Ste ps of research 2.5.1 Record information before treatment: Administrative information: age, gender, Symptoms of function, entity, pulp tests, X-ray examination, diagnosis according to medical record 2.5.2 Investigation of root canal characteristics of teeth on periapical film: The digital periapical film was taken with Yoshida machine (Japan) Survey the number of roots, the number of root canals, determining whether or not there is any periapical damage 2.5.3 Investigation of root canal characteristics of pre-treated teeth on CBCT: CBCT taken with PlanmecaProMax 3D system (Finland), endodontic mode, parameters: 5mA / 96kV / 12s / Ø 5,7x5,7cm / 200µm The data is exported into the DICOM file format (Digital Imaging and Communications in Medicine) Analyze image on computer with PlanmecaRomexis software (Finland) in planes: axial, coronal, sagital plane.Each film is read times at intervals of week, using a magnifying glass 2.5.3.1 Investigation of root number, root canal number, appearance of Second mesiobuccal canal 2.5.3.2 Measure the distance between the orifices of canals 2.5.3.3 Noting the phenomenon of Fused Root teeth 2.5.3.4 Investigation of root canal morphologyof mesiobuccal root 2.5.3.5 Root canal curvature measurement 2.5.3.6 Evaluation of periapicallesions on CBCT Record periapical lesions in each root Use the length measurement tool to measure the optical circumference around the apex in the axial, coronal, sagital plane if available, choosing the largest size 2.5.3.7 Evaluate correlation of root and maxillary sinus floor: 2.5.3.8 Evaluation of maxillary sinus mucosa thicknessbefore and after treatment: 2.5.4 Root canal treatment 2.5.4.1 Cleaning, shaping root canal system: Shaping root canal system by Crown-Down technique with Ni-T i Protaper rotating files 2.5.4.2 Obturating root canal system: Dry the canal Apply AH Plus at coronal third wall Warm the T hermafil, insert it to the working length Vert ical compress t he GP around the plastic core Additional GP if needed Wait for GP to stabilize, cut the shaft of Thermafil at the canal orifice T emporary cavity obturating with Caviton T ake CBCT film to check after obturating Figure 2.21 Root canalfilling results on coronal slices of mesiobuccal root of First maxillary molars 11 2.8 Error control: Standardize treatment techniques, surveys, and assessments T he process of inputting data into the machine is checked and reconciled times 2.9 Ethics in research: T he study is conducted after the scientific council of the 108 Clinical Medical Sciences Research Institute adopts the outline, following the ethical principles of human research Chapte r RESULTS 3.1 General characte ristics of the sample Table 3.1 Distribution of patients by age and gender Gende r Male Fe male Total Age group n % n % % n 18-34 yrs 10 18,2 12,7 30,9 17 35-44 yrs 7,3 12 21,8 29,1 16 45-60 yrs 14 25,5 14,5 40,0 22 100,0 Total 28 51,0 27 49,0 55 Research on 55 t eeth of 50 patients from 18 t o 60 years, divided into age groups: 45-60 years old, 18-34 years old, 35-44 years old, the corresponding rates are: 40.0%, 30, 9%, 29.1% 3.2 Morphological characteristics of the root and root canal system of First and second maxillary molars on CBCT Table 3.3 Root Number of First and second maxillary molars(M.M.) roots roots Total Tooth n % n % n % First M.M 0 28 100 28 100 Second M.M 11,1 24 88,9 27 100 All the First maxillary molarshave roots, 88.9% of second maxillary molars has roots, 11.1% has roots 12 Table 3.4 Root canal number of First and second maxillary molars canals canals canals canals Total Tooth First M.M Second M.M n % 7,4 n 11 18 % 39,3 66,7 n 16 % 57,1 25,9 n % 3,6 % 100 100 n 28 27 57.1% of First maxillary molars have canals, 39.3% have canals, 3.6% have canals 66.7% of Second maxillary molarshave canals, 25.9% has canals, 7,4% have canals Table 3.5 Canal number in each root of First maxillary molars Canal number n % First maxillary molars Mesiobuccal root canal canals canal canals canal Distobuccal root Palatal root 11 17 27 28 39,3 60,7 96,4 3,6 100 100% of the palatal root has canal, 96.4% of the distobuccal root has canal, there is 3.6%of the distobuccal root having canals 60.7% of the mesiobuccal root has canals, the rest has canal Table 3.6 Canal number in each rootof Second maxillary molars Second M.M Root Canal n % Roots mesiobuccal root Canal 17 70,8 distobuccal root Roots palatal root buccal root palatal root Canals Canal 24 29,2 100 Canal Canal Canals Canal 24 100 66,7 33,3 100 In roots molars: 100% of palatal and distobuccal root have canal, 70.8% of mesiobuccal root have canal, 29.2% have 13 canals In roots tooth: 100% of palatal root has canal, 66.7% of buccal root has canals, 33.3% has canal Table 3.12 The ratio of second mesiobuccal canal (MB2)in first and second maxillary molars on CBCT and periapcal (PA) film Film PA CBCT P MB2 canal n % n % With MB2 5,8 24 46,2