Radiographic Anatomy of Mandible

Radiographic Anatomy of Mandible

Mandible - Postero-Anterior View

Mandible - Oblique View

Mandible – Lateral View

Orthopantogram (OPG)

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Radiographic Anatomy of Facial Bones and Mandible with Radiological Abnormalities of the Skull and Facial Bones

Radiographic Anatomy of Facial Bones and Mandible with Radiological Abnormalities of the Skull and Facial Bones

Radiographic Anatomy of Facial Bones

Postero-Anterior Caldwell View

Occipito Mental (OM) (Waters) View

Postero-Anterior 30° (Modified Parietocanthial)

Occipito Mental 30° (OM30) View

Submentovertex (SMV) / Slit Basal / Jughandles View

Adult Facial Bones - Lateral View

Slit Townes View

Abnormalities of the Skull and Facial Bones
Cause	Radiological Features
Enlargement of Skull Vault
Children
Hydrocephalus	Sutural  diastasis, increased convoluted markings, “copper beaten skull”
Raised intra cranial pressure	Bulging of fontanelle in infancy.
Adults
Acromegaly	Enlarged frontal sinuses and mandible, erosion and enlargement of sella turcica
Paget’s disease	Thickened skull vault, increased density of vault and facial bones.
Increased Density
Localised
Hyperostosis frontalis	Symmetrical thickening of the inner table of skull vault, usually in women, of no significance.
Meningioma	Area of  localised sclerosis, possible enlarged groove of feeding artery.
Fibrous displasia	Asymmetrical, affecting the facial bones maxilla and base of skull.
Generalised
Paget’s disease	Irregular sclerosis with thickened vault.
Secondary deposits. e.g. prostate & breast	Irregular sclerosis, thickened vault.
Lytic lesions
Childhood
Secondary deposits, neuroblastoma, leukaemi	Variable appearances,  Sutural deposits may mimic sutural diastasis.
Eosinic granuloma, Histiocytosis X	Transradient defect with bevelled edges.
Adults
Myelomatosis	Rounded translucent (2-10mm) multiple ‘holes’
Secondary deposits	Generally ill defined translucent patches.
Hyperparathyroidism	Mottled appearance of ‘pepper pot’ skull.
Paget’s	Sharply defined zones affecting large areas of the vault.

Radiographic Anatomy of Mandible

Mandible - Postero-Anterior View

Mandible - Oblique View

Mandible – Lateral View

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A NOTE ON PTERYGOPALATINE FOSSA

A NOTE ON PTERYGOPALATINE FOSSA

PTERYGOPALATINE FOSSA

The pterygopalatine fossa—

           A small, pyramid-shaped space.

           Situated between the maxilla, sphenoid, and palatine bones.

           It communicates via canals, fissures, and foramina with various regions of the skull.

          The contents of the pterygopalatine fossa include

                     The terminal portion of the maxillary artery;

                     The pterygopalatine ganglion;

                     The maxillary division of the trigeminal nerve; and branches of these structures.

Maxillary Artery

The third, or pterygopalatine portion, of the maxillary artery enters the pterygopalatine fossa from the infratemporal fossa via the pterygomaxillary fissure

Maxillary artery and its distribution in the deep face

Branches of the pterygopalatine portion of the maxillary artery are the posterosuperior alveolar, infraorbital, greater palatine, pharyngeal, and sphenopalatine arteries as well as the artery of the pterygoid canal.

The posterior superior alveolar artery branches from the maxillary artery as that vessel enters the pterygomaxillary fissure. It travels on the maxillary tuberosity and enters the posterior superior alveolar foramen accompanied by the like-named nerve. The vessel ramifies within the maxilla to vascularize the maxillary sinus, molars, and premolars as well as the neighboring gingiva.

The infraorbital artery, a continuation of the maxillary artery, enters the orbit through the inferior orbital fissure, lies in the infraorbital groove, leaves the orbit via the infraorbital canal, and enters the face by way of the infraorbital foramen. Branches of the infraorbital artery are the orbital branches, serving the lacrimal gland and the inferior oblique and inferior rectus muscles; the anterior superior alveolar branches, which vascularize the anterior teeth and the maxillary sinus; and the facial branches.

The greater palatine artery and its branch, the lesser palatine artery, pass through the pterygopalatine canal and gain entrance to the palate via the greater palatine and lesser palatine foramina, respectively, to vascularize the hard and soft palates as well as associated structures. The pharyngeal branch passes dorsally, through the pharyngeal canal, to vascularize the auditory tube, sphenoidal sinus, and portions of the pharynx. The sphenopalatine artery leaves the pterygopalatine fossa via the sphenopalatine foramen on its medial wall to enter the nasal fossa. The distribution of this vessel and its branches is discussed later in this chapter. The small artery of the pterygoid canal passes through the posterior wall of the pterygopalatine fossa via the pterygoid canal. It supplies part of the auditory tube, pharynx, middle ear, and sphenoidal sinus.

Maxillary Nerve

The maxillary division of the trigeminal nerve enters the pterygopalatine fossa at its posterior boundary via the foramen rotundum. While in the fossa, it gives off the zygomatic nerve, which, passing into the orbit through the inferior orbital fissure, will bifurcate to form the zygomaticotemporal and zygomaticofacial nerves.

The maxillary division of the trigeminal nerve

The posterior superior alveolar nerves also branch from the maxillary nerve, exit the fossa via the pterygomaxillary fissure, and enter the maxillary tuberosity to serve the maxillary sinus, molars, and adjacent gingiva and cheek. The maxillary nerve then enters the orbit by way of the inferior orbital fissure and is referred to as the infraorbital nerve.

While in the pterygopalatine fossa, the maxillary nerve communicates with the pterygopalatine ganglion via two small trunks, the pterygopalatine nerves; however, these nerves do not bear a functional relationship with the ganglion. Postganglionic parasympathetic fibers derived from the ganglion ride along and distribute with branches of the maxillary division of the trigeminal nerve.

Pterygopalatine ganglion and associated nerves and arteries

Orbital branches are slender nerves that supply the periosteum of the orbit and the mucoperiosteum of the ethmoidal and sphenoidal sinuses. The greater palatine nerve and its branches, the lesser palatine and posterior inferior nasal branches, descend through the pterygopalatine canal to supply regions of the palate, gingiva, tonsil, and lateral wall of the nasal fossa.

Posterior superior nasal branches leave the pterygopalatine fossa via the sphenopalatine foramen to serve the posterior aspect of the nasal fossa and part of the ethmoidal sinus. Its nasopalatine branch grooves the vomer bone in its path to the incisive foramen of the anterior hard palate, which it supplies. The pharyngeal nerve traverses the pharyngeal canal to innervate part of the nasopharynx.

Pterygopalatine Ganglion

The pterygopalatine ganglion seems to be functionally associated with the maxillary division of the trigeminal nerve because it is suspended by the pterygopalatine nerves within the fossa. It is, however, a parasympathetic ganglion of the facial nerve (cranial nerve VII).

This ganglion receives its parasympathetic preganglionic root by way of the pterygoid canal, which opens onto the posterior wall of the fossa. The preganglionic parasympathetic fibers synapse with postganglionic parasympathetic cell bodies within the ganglion. Postsynaptic parasympathetic fibers leave the ganglion and distribute with branches of the maxillary division of cranial nerve V. These fibers are secretomotor in function. They provide parasympathetic flow to the lacrimal gland and mucosal glands of the nasal fossa, palate, and pharynx.

         

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A Note on Anterior cross bite

A Note on Anterior cross bite

Anterior cross bite

Possible causes

Class III skeletal pattern

               Crowding

Retained primary teeth and roots  

Presence of supernumerary teeth

Clinical features

• Instanding maxillary incisor occluding behind the corresponding lower incisors.
• Over bite which can vary from nothing to excessive depth.
• Gingival recession of the lower incisor involved.
• Forward displacement of the  mandible-  instanding tooth comes into premature contact along the normal path of closure.
•      mobility of the lower incisor involved in the cross bite

Methods available for correction

Spoon handle biting.

Removable appliance with either cantilever spring or screw.

Lower inclined bite plane.

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Describing Radiographic Lesions

 Describing Radiographic Lesions

Describing radiographic lesions can be a tricky thing at first, but with practice and radiographic examples it starts to become second nature. The acronym below I created for my students when teaching them how to describe radiographic lesions. The entire acronym applies to intraosseous (within bone) lesions. Not all the letters/topics apply to all radiographic lesions

L – Location
E – Edge
S – Shape
I – Internal
O – Other Structures
N – Number

L – Location
Position in the Jaws
A) Identify the loca'tion in the jaws ie – maxilla versus mandible and anterior versus posterior

Localized or Generalized
A) If an abnormal appearance affects all the osseous structures of the mandible or maxilla of both jaws the entity is generalized

B) If the entity is confined to one quadrant or area, it is localized. It may be unilateral orbilateral


E – Edge

Identify whether the edge of the abnormality is well-defined, ill-defined or well-localized

A- A well-defined entity has a sharp boundary that allows the entire edge of the lesion to be traced. The surrounding bone of a well-defined lesion appears normal up to the edge of the abnormality. Some well-defined borders have a radiopaque border and are classified ascorticated. A corticated border can be thin to thick

B- An ill-defined entity is a gradual transition between normal appearing bone and the abnormal bone of the lesion. The border of the lesion cannot be traced and the boundaries of the lesion are not clear

C- A well-localized entity is visible in a specific area but the borders may not be clearly identified around the entire lesion.


S – Shape

Identify the general shape of the abnormality. Common shapes include circular, ovoid, linear or scalloped


I – Internal structure

Radiolucent

Identify if the entire internal aspect of the abnormality is completely radiolucent. Further classification includes unilocular versus multilocular

A- Unilocular is completely radiolucent
B- Multilocular has bony septum within the entity

Radiopaque
A) Identify if the entire internal aspect of the abnormality is completely radiopaque

B) Determine the radiopacity of the interanal aspect. For example – similar radiopaicyt to tooth structure, bone, etc

Mixed Radiolucent/Radiopaque

Identify if the internal aspect is a mixture of radiolucent and radiopaque areas


O – Other structures

Teeth
Identify if the adjacent teeth are being displaced or resorbed

Evaluate which direction the teeth are displaced

Evaluate where the resorption is occurring – ie midroot or apex

Inferior Alveolar Nerve Canal

A) Identify any changes to the course of the canal. Note if the canal being displaced inferiorly or superiorly

B) Identify if there are changes to the size of the canal. Is it being enlarged or smaller than what is within the range of normal

Cortical Bone

A) Identify any changes in the thickness of the cortical bone. Is there thinning or the cortical bone in the area of the abnormality

B) Identify any changes in the loca'tion of the cortical bone. Is the cortical bone being displaced inferiorly, superiorly, lingually or facially


N – Number

Single or Multiple
A) If there is one abnormality, it is a single entity

B) If there is more than one site throughout the jaws, it is multiple

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Burket's Oral Medicine

             

                 Burket's Oral Medicine

                      

                                            Download Link

                                       http://ryushare.com/427beb88a5e6 

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Fundamentals of Tooth Preparation for Cast Met'al and Porcelain Restorations

Fundamentals of Tooth Preparationfor Cast Met'al and Porcelain Restorations

Shillingburg

Book Chapters:

1. Biomechanical Principles of Preparations
2. Finish Lines and the Periodontium
3. Instrumentation
4. Full Veneer Crowns
5. Maxillary Posterior Three-Quarter Crowns
6. Mandibular Posterior Three-Quarter Crowns
7. Anterior Three-Quarter Crowns
8. Pin-Modified Three-Quarter Crowns
9. Seven-Eighths Crowns
10. Proximal Half-Crowns
11. Inlays
12. MOD Onlays
13. Anterior Porcelain-Fused-to-****l Crowns
14. Posterior Porcelain-Fused-to-****l Crowns
15. All-Ceramic Crowns
16. Preparation Modifications for Damaged Teeth
17. Preparation Modifications for Special Situations

Download Link
http://goo.gl/DPbWY

PASSWORDroomi

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