Paralleling and bisecting radiographic techniques

this is the seminar for Undergraduate students consisting of initial paralellelig and bisecting radiographic techniques, history, types, size, extraoral films, technical errors, radiographic examination in special children

1. PARALLELING AND BISECTING RADIOGRAPHIC TECHNIQUES Presented by: Ritu Gupta BDS- Final year

2. CONTENTS INTRODUCTION HISTORY TYPES OF RADIOGRAPH SIZE OF INTRAORAL FILMS EXTRAORAL FILMS INTRAORAL PERIAPICAL RADIOGRAPH PARALLELING TECHNIQUE BISECTING ANGLE TECHNIQUE PROBABLE TECHNICAL ERRORS RADIOGRAPHIC EXAMINATION IN SPECIAL CHILDREN GAG REFLEX BIBLIOGRAPHY

3. INTRODUCTION A conventional radiograph is a 2-D projection image of a 3-D object in which an entire volume of tissues between the X- ray source and the film is projected onto the 2-D image. Radiographic examination plays a vital role in the diagnosis and treatment planning of both children and adult.

4. In pediatric dentistry radiographs also plays a significant role in assesment of growth and development . It also helps in detection of -dental caries - diagnosis of cysts -tumors

5. HISTORY The work of many scientists culminates in discovery of X-rays by ROENTGEN on Nov- 8,1895. X-ray was named by ROENTGEN because of simple fact that the nature of these rays was not known at that time of discovery.

6. TYPES OF RADIOGRAPHS Radiographs of a pedo patient are categorized in two groups- 1. Intra-oral radiographs 2. Extra-oral radiographs According to the films used in radiographic examination it can be- 1. Intra-oral films 2. Extra-oral films

7. INTRAORAL FILMS They are meant for positioning inside the mouth during exposure. There are three types of intraoral radiograph projection- 1.Intraoral periapical radiograph (IOPA) 2. Bitewing radiographs 3. Occlusal radiographs

8. IOPA BITEWING RADIOGRAPH OCCLUSAL RADIOGRAPH TYPES OF INTRAORAL RADIOGRAPH PROJECTIONS

9. SIZE OF INTRAORAL FILMS Size 0(22x35 mm)- used for bitewing and periapical radiographs of small children. Size 1 (24x40mm)- used for radiographing anterior teeth in adults. Size 2 (31x41mm )- standard film Size 3 (57x76mm)- used for posterior bitewing examination. Occlusal film (57x76mm)- used for visualizing the entire maxillary or mandibular arch.

10. Size of intraoral films

11. EXTRAORAL FILM Extra-oral films used in dental practice vary in their sizes depending on individual projection for which they are employed. 5x7 inches films -used for TMJ views and lateral oblique views. 8x10 inches films -uses for lateral cephalometry and paranasal sinus view. 6x12inches films

12. INTRAORAL PERIAPICAL RADIOGRAPH (IOPA) IOPA radiographs are useful in the evaluation of teeth and their associated structures. IOPA radiograph can be taken by using two techniques- 1. Short cone technique or bisecting angle technique. 2. Long cone technique or paralleling technique .

13. PARALLELING TECHNIQUE PRINCIPLE - X-ray film is placed parallel to the long axis of teeth and the central ray is directed at right angle to teeth and film. Since the film is placed farther away from the object ,a film holder is necessary.

14. ADVANTAGES Better dimensional accuracy. No superimposition of structure like zygomatic arch. Head position is not critical .

15. DISADVANTAGES As the small size of mouth in children precludes the placement of film beyond the apical region of teeth. Less comfortable. More limited.

16. BISECTING ANGLE TECHNIQUE PRINCIPLE-Based on simple geometric theorem- cieszynskis “ rule of isometry ”. It basically states that two triangles are equal if they have equal angles and a common side. The central ray is directed perpendicular to a plane that bisects the angle created by long axis of teeth and film.

17. In small children with primary dentition size-0 film should be used. Older children or in situation where large area is visualized size-1 film should be used.

18. INDICATIONS To identify any pathology involving primary teeth such as periapical pathology or internal resorption. In analysis of space in mixed dentition. To evaluate status of periodontal ligaments. To detect developmental anomalies-supernumerary or un-erupted teeth To diagnose pulp calcification , root resorption and root development. To diagnose traumatic injuries.

19. TECHNIQUE OBTAINING CHILD’S COOPERTION FOR RADIOGRAPH- Explain the child what you are planning to do. Obtain the confidence and cooperation of child. Talk to child to distract his attention and establish confidence.

20. PROJECTIONS For maxillary teeth- head of the patient should be upright. For posterior projection-film is kept on lingual sulcus. For lower anterior projection-film is kept on floor of mouth.

21. PROBABLE TECHNICAL ERROR FOR A PEDIATRIC PATIENT In general there is no scientific difference in technique applied for children and adult radiograph , but some errors can be commonly seen – Improper placement of film. Cone cutting. Overexposure. High exposure to patient to radiation because of repeated radiographic examination Incorrect vertical angulation. Incorrect horizontal angulation.

22. RADIOGRAPHIC EXAMINATION IN SPECIAL CHILDREN 18 inch (46cm) length floss is attached through a hole made in tab. The patient should wear lead apron with a thyroid shield and anyone who helps hold the patient and the films.

23. GAG REFLEX The patient should be advise to breath rapidly through nose. Stimulating the posterior closure of tongue or soft palate initiate the gag reflex. In extreme case a topical anesthetic agent can be applied.

24. BIBLIOGRAPHY White S. , Pharoah M. Oral Radiology: Principles and Interpretation. 1 st South Asia Edition. New Delhi (India) : Elsevier India ; Sept 2014. Tandon S. Textbook of Pedodontics . 2 nd edition. Hyderabad (India) : Paras Medical Publisher ; 2009 Ghom AG. Basic Oral Radiology. 3/e. New Delhi (India) : Jaypee Brothers Medical Publishers (P) Ltd ; 2014