Bitewing & Occlusal Techniques PDF

Bite-Wing and Occlusal Radiography Prof. Hossam Kandil Oral and Maxillofacial Radiology Cairo University Learning Objectives State the basic principle of the bitewing technique. Describe the purpose and use of bite-wing technique. Describe the patient and the film placem...

Bite-Wing and Occlusal Radiography Prof. Hossam Kandil Oral and Maxillofacial Radiology Cairo University Learning Objectives State the basic principle of the bitewing technique. Describe the purpose and use of bite-wing technique. Describe the patient and the film placement for the premolar-molar bite-wing views.. Describe the purpose of occlusal examination. List the uses of each occlusal view. Describe the patient, film and angulations during occlusal projection. State the purpose of localization techniques. Describe the different localization techniques. Bitewing Technique (interproximal radiograph)  Indications Detection and monitoring proximal caries. Assessment of existing restorations and detection of overhanging margins. Assessment of the alveolar bone crest, monitoring changes in marginal bone height and evaluating periodontal conditions.. Detection of inter-proximal calculus. Detection of pulp stones. Types 1- horizontal B.W.: long axis of the film orienting parallel to the occlusal plane. 2- vertical B.W.: which is usually used when the patient has moderate to extensive bone loss, thus orienting the film vertically increases the possibilities to record upper and lower residual alveolar ridges. Principle and Procedure Patient Position: The head is normally positioned so that the maxillary arch is parallel to the floor and the mid-sagittal plane is perpendicular to the floor.  Film Placement The film is placed in the mouth parallel to the crowns of both upper and lower teeth. The tab should be positioned parallel to the upper and lower edges of the film packet. The film is stabilized when the patient bites on the bite wing tab.  The film should be placed in contact with the teeth or as close as possible. The film edge should be placed parallel to the dental arch. Vertical BW horizontal BW  Vertical Angle The central ray is directed through the contacts of the teeth, using a zero to +10 degrees vertical angulation. This angulation is recommended for the bite-wing radiograph to compensate for the slight bend of the upper portion of the film and the curvature of the maxillary teeth. Horizontal Angle To adjust the horizontal angulation, the central ray must be directed through the contact areas between the teeth to be at right angle to both the film and tooth Correct HA Incorrect HA Ideal exposure factors for B.W. Assessment of caries and restorations: film should be well exposed and show good contrast so that DEJ is seen. Assessment of periodontal status: film should be under-exposed to avoid burn-out of thin alveolar crest bone.  What is occlusal radiography? It is defined as those intra-oral radiographic techniques where the film packet is placed on the occlusal plane. It displays a relatively larger segment of the dental arches (maxilla or mandible) and may include palate and floor of the mouth with reasonable extent of contiguous lateral structures. Pediatric size Indication of occlusal radiograph It provides us with the 3rd dimension so we can: Locates roots, supernumerary teeth and impacted canines. Localizes foreign bodies in the jaw bones. Localizes fractures of jawbone with better determination of its nature, extent and degree of displacement. Determines the B-L extent of jaws lesions. Foreign bodies Other indications Localizes stone of salivary glands. Examines the anterior, medial and lateral walls of the maxillary sinus. In patient with trismus. Used with uncooperative children or handicapped patients. Examination of area of cleft palate. Measuring changes in the size and shape of maxilla and mandible. Types of occlusal views Occlusal Views Topographic Views Cross-sectional views Anterior Lateral Topographic Topographic Principle Of Topographic Projection * It is the same as bisecting angle- technique. Axis of upper Central ray teeth bisector *The central ray is directed perpendicular on the bisector bisecting the angle between film the long axis of the teeth and the plane of the film. Axis of lower teeth  Principle of Cross-sectional Technique The central ray is directed perpendicular on the film Central ray VA= 90 HA= 0 film In case of the mandible: can be done In case of maxilla, we do some modification to avoid vital organs. Otherwise use occlusal cassette Maxillary projections 1- Anterior maxillary Topographic 1- Patient position: upright 2- Film placement: Horizontally 3- tube-head position: VA= 65 HA=0 Point of entry= above the bridge of the nose at the Nasion.  Indications (Image field) Periapical assess. of ant. teeth in children or in cases of trismus. Detection of un-erupted canines, supernumerary teeth and odontomas. Extension of lesions in anterior maxilla. Assess. Of fracture of ant. Teeth or alveolar bone.  2- lateral maxillary Topographic projection 1- patient position: Upright 2- Film placement : long axis parallel to MSP. 3- tube-head position: VA= 55 HA= 90 Point of entry = 2cm below the outer canthus of the eye  Indication (lat. Maxillary) Periapical assess. of upper posterior teeth (shows from lateral incisor to contralateral last molar). Evaluation of extent of lesion in posterior maxilla. assess. of floor of the maxillary sinus. Assess. of fracture in posterior teeth, alveolar bone and tuberosity. Maxillary cross-sectional projection Patient position: upright Film placement: long dimension perpendicular to the MSP in the mouth Tube head position: VA: + 90 HA: 0 Point of entry: above the head of the patient at the hairline on the vertex of the skull.  Indication (maxillary cross-sectional) It shows the palate, zygomatic process of the maxilla, the antro-inferior aspect of the sinuses, nasolacrimal canals, nasal septum and teeth from second molar to second molar. Modified Cross-sectional  Mandibular Occlusal Projections 1- Anterior Topographic View Patient position: patient is tilted back so that the occlusal plane is 45degrees above the horizontal plane Film placement: Long axis is perpendicular to MSP Tube head: VA = -45. HA= 0 Point of entry is below the chin at the midline Indication of mandibular anterior view Periapical assess. of lower anteriors. Evaluate size, extent of lesions in anterior mandible. Assess. of displaced fracture in anterior area.  Lateral Topographic Mandibular View Patient Position: the patient’s head is supported and then rotated away from the side under investigation and the chin is raised. The film packet with the white surface facing downwards is inserted into the mouth with its long axis antero-posteriorly. Cone is aimed upwards and forwards towards the film, from below and behind the angle of the mandible approximately 3cm lateral to the midline and 3cm posterior to the chin. V.A. -45  Indications of lateral mandibular view It provides an image for half the floor of the mouth if we reduce the exposure factors. B and L cortical plates of half of the mandible. The teeth from lateral incisor to the contralateral third molar for impaction, supernumerary or odontoms.  Mandibular Cross-sectional View 1- Patient position: the patient tips the head as far as is comfortable while it is supported. 2- Film placement: Long axis perpendicular to the sagittal plane 3- Tube head: from below the patient's chin in the midline (3 cm behind the chin), at an angle V.A.: -90 to the film.  Indications of mandibular cross-sectional Detection of the presence and position of SM SG calculi. All assessments in BL direction (impaction, supernumerary and lesions) Assessment of displacement of fracture in a horizontal plane. a- Normal b- Pathological lesion c- SG stones Uses of Occlusal Films in Extr-Oral Radiography Although the occlusal film is one of the intra-oral films, however it may sometimes be used as an extra-oral film. Intensifying screens and occlusal cassettes can be used in some cases with the occlusal films, this is used during the production of maxillary cross-sectional occlusal view to reduce exposure time and eliminate exposure of vital cranial structures to extra radiation.  The occlusal film can be used extra-orally in the following cases: Trismus and uncooperative children: occlusal film can be used as lateral oblique film (will be discussed later). Symphyseal fracture of the mandible (reverse topographic view): the film is held against the inferior border of the mandible below the chin and the central ray is directed at the midline of the chin with V.A. +75.  Stones in the stensen’s duct of the parorid gland: the film is placed posterior to the cheek surface and the central ray is directed perpendicular to the surface of the film while the patient is blowing his cheek outward (Puffing technique).