TEMPOROMANDIBULAR JOINT Submitted by: Batallones, Amery Rose Galeno, Chris Carlo Saunar, Maurice Cheekz Talag,Bryan Matthew Ursal, Alyssa Mae Villacorta, Aimee Carmina
TEMPOROMANDIBULAR JOINT This is the articulation between the condylar head of mandible and the anterior part ofthe glenoid fossa of two temporal bones. The mandibular articulation with the skull on eachside is better termed as Craniomandibular Joint since the articulation is between the movablemandible and the immovable cranium or skull. The articulation is bilateral because the left andright sides work as a unit and this is the only visible free moving articulation in the head. Temporomandibular Joint has distinct features compared to the other joints: Thecoordinated movements of the right and left joints are complex and usually are controlled byreflexes. Both the maxillae and mandible carry teeth whose shape and position greatly affectthe most closed portions of mandibular movements. The articulating surface of the TMJ is notformed of Hyaline cartilage but of a sturdy avascular fibrous layer. TMJ is the only synovial jointin the body with articulating disc which is present between the joint surfaces of cranium andmandible which makes it a double joint.Classification of Joints Joints are classified in various ways. Most common and simplistic classifications areFibrous joints, Cartilaginous joints, and Synovial Joints.Fibrous Joints In a fibrous joint two bones are connected by fibrous tissue and 3 types are describedunder this classification of joint, the first type is the suture, it is a joint that permits little or nomovement. Articulation by processes and indentations interlocked together. Its histologyclearly indicates that the function is to permit growth, since the articulating surfaces arecovered by an osteogenic layer which is responsible for new bone formation to maintain thesuture as the skull bones are separated by the expanding brain. The second type of fibrous jointis gomphosis, articulation formed by the insertion of a conical process into a socket. It is seen inthe articulation of the teeth with the alveoli of the maxillary bones. In gomphosis, thefunctional movement is restricted to intrusion and recovery in response to biting forces. Thethird type of fibrous joint is syndesmosis, surfaces are united by interosseous ligament thatpermits limited movement. Common examples are the joints between tibia and fibula, andradius and ulna.
Cartilaginous Joints Cartilaginous joints are classified into primary cartilaginous joints or secondarycartilaginous joints. In a primary cartilaginous joint, bone and cartilage are in direct apposition.An example is the articulations of the ribs with their cartilages (costo-chondral). In a secondarycartilaginous joint, the tissues of articulation occur in the sequence bone-cartilage-fibroustissue-cartilage-bone. An example is the pubic symphysis. Cartilaginous joints and fibrous jointspermit little if any movement between the bones involved.Synovial Joints In synovial joint, which generally permits significant movement, two bones are unitedand surrounded by a capsule that creates a joint cavity. This cavity is filled with synovial fluidformed by the synovial membrane. The cavity may be divided by an articular disk. Variousligaments are associated with synovial joints to strengthen the articulation and check excessmovement. Synovial joints are further classified by the number of axes in which the bonesinvolved can move: uniaxial- all movements take place around one axis. Ex. Ginglymus and Pivot-joint biaxial- movements around two horizontal axes at right angles to each other or at any intervening axis between the two. Ex. Condyloid and Saddle-joint multiaxial/polyaxial- movements around more than two axes. Ex. Ball-and-socket joint Synovial joints are also classified by the shapes of the articulating surface: a. Planar- a synovial joint in which the opposed surfaces are flat or only slightly curved. b. Ginglymoid- articular surfaces are molded to each other in such a manner as to permit motion only in one plane, forward and backward. c. Pivot- movement is limited to rotation; the joint is formed by a pivot-like process turning within a ring. d. Condyloid- one in which an ovoid head of one bone moves in an elliptical cavity of another, permitting flexion, extension, adduction, abduction and circumduction, but not axial rotation.
e. Saddle- one having two saddle-shaped surfaces at right angles to each other. Same movement with condyloid articulations. f. Ball-and-socket- form of joint in which the distal bone is capable of motion around an indefinite number of axes which have a common center. Movements of a synovial joint are initiated and affected by muscles working together ina highly coordinated manner. This coordination is achieved through the joint’s sensoryinnervation which establishes Hilton’s Law, the principle that the nerve supplying a joint alsosupplies both the muscles that move the joint and the skin covering the articular insertion ofthose muscles.Type of joint of Temporomandibular Joint The Temporomandibular joint articulation is a synovial joint and described as synovialsliding-ginglymoid joint articulation because its movements are combination of glidingmovements and a loose hinge movement and also the condyle undertakes rotationalmovements which is the initial movement of the jaw when the mouth opens and translationalmovements which is the secondary gliding motion of jaw as it is opened widely.Innervation and Vascularization Sensory innervation of the temporomandibular joint is derived fromthe auriculotemporal and masseteric branches of mandibular branch of the trigeminal nerve. The arterial blood supply is provided by branches of the external carotid artery,predominately the superficial temporal branch. Other branches of the external carotid arterysuch as deep auricular artery, anterior tympanic artery, ascending pharyngeal artery,and maxillary artery also contribute to the arterial blood supply of the joint. The specific mechanics of proprioception in the temporomandibular joint involve fourreceptors. Ruffini endings function as static mechanoreceptors which position themandible. Pacinian corpuscles are dynamic mechanoreceptors which accelerate movementduring reflexes. Golgi tendon organs function as static mechanoreceptors for protection ofligaments around the temporomandibular joint. Free nerve endings are the pain receptors forprotection of the temporomandibular joint.
In order to work properly, there is neither innervation nor vascularization within thecentral portion of the articular disc. ANATOMY AND HISTOLOGY I. Anatomy (Bony Structures): The temporomandibular joint (TMJ) consists of the condylar head of the mandible articulating with the glenoid or temporomandibular fossa of the temporal bone. The articulating surface of the temporal bone is convex anteriorly at the tubercle and concave posteriorly at the fossa. The articulating surface of the condyle and the opposing surface of the temporomandibularfossa, including the anterior tubercle, are covered by fibrocartilage. Chondrocytes in theposterior aspect of the mandibular condyle, a region exposed to greater tensional forces thancompression, express collagen types I and II. The condyle of the mandible is composed of cancellous bone covered by a thin layer ofcompact bone. The trabeculae are grouped in such a way that they radiate from the neck of themandible and reach the cortex at right angles, thus giving maximal strength to the condyle. Thelarge marrow spaces decrease in size with progressing age by a marked thickening of thetrabeculae. The red marrow in the condyle is the myeloid or cellular type. In older individuals itis sometimes replaced by fatty marrow. During the period of growth layer of hyaline cartilage lies underneath the fibrouscovering of the condyle. This cartilaginous plate grows by apposition from the deepest coveringconnective tissue. At the same time its deep surface is replaced by a bone. Remnants of thiscartilage may persist into old age.
The roof of the mandibular fossa consists of a thin compact layer of bone. The articulartubercle is composed of spongy bone covered with a thin layer of compact bone. In rare cases,islands of hyaline cartilage are found in the articular tubercle. Articular fossa is resembles the long axis of that of the condyle. The root of the fossa isvery thin, indicating that the role of this part of the joint is rather passive. The deeper part ofthe fossa apparently acts more or less as a bed for the thicker posterior part of the articular discwhen it is resting in its most posterior position. The articular surface proper is the posterior andinferior part of the articular eminence , which is a roll of bone, more or less steep in itsposterior slope, with an anteroposterior curvature of variable constricture. It has already been pointed out that the cranial and mandibular surfaces of the jointsare not congruent. They do not touch each other even when the teeth are in intercuspalcontact. The distance from the articular surface of the condyle to the opposing cranial surface isfilled by an articular disc.II. Histological Part:Articular Capsule It is attached to the fossa, to the tubercle of the temporal bone, and to the neck of thecondyle. It is consist of an outer fibrous layer that is strengthened on the lateral surface to formthe temporomandibular ligament. The inner or synovial layer is a thin layer of connective tissue.It contains numerous blood vessels that form a capillary network close to its surface. From itssurface, folds or fingerlike processes (synovial folds or villi) protrude into the articular cavity. Afew fibroblast of the synovial membrane reach the surface and, with some histiocytes andlymphatic wandering cells, form an incomplete lining of the synovial membrane. A small amount of a clear, straw-colored viscous fluid, synovial fluid, is found inthe articular space. It serves as a: 1. Lubricant: As it the principal role of synovial fluid is to reduce friction between the articular cartilage of synovial joints during movement. 2. Nutrition: Providres as fluid for the avascular tissues covering the condyle and the anterior tubercle and for the disc.
3. Regulatory: Separates the articular disk from the articulating surfaces. This is elaborated by diffusion from the rich capillary network of the synovialmembrane, augmented by mucin possibly by the synovial cells.Articular Disk In young individuals, it is composed of dense fibrous tissue. The interlacing fibers arestraight and tightly packed. Elastic fibers are found only in relatively small numbers. Thefibroblast in the disc are elongated and send flat cytoplasmic winglike processes into theintertices between the adjacent bundles. With advancing age, some of the fibroblast develop into the chondroid cells, which latermay differentiate into true chondrocytes. Even small islands of hyaline cartilage may be foundin the discs of the older persons. Chondroid cells, true cartilage cells, and hyaline groundsubstance develop in situ by differentiatin of the fibroblast. In the disc as well as in the fibroustissue covering the articular surfaces this cellular change seems to be dependent uponmechanical influences. The presence of chondrocytes may increase the resistance andresilience of the fibrous tissue. The fibrous tissue covering the articular eminence and mandibular condyle as well asthe large central area of the disc is devoid of blood vessels and nerves and has limited ability.Articular Surface of the Temporal Bone The fibrous layer covering the articulating surface of the temporal bone is thin in thearticular fossa and thickens rapidly on the posterior slope of the artcular tubercle. In this region,the fibrous tissue shows a definite arrangement in two layers, with a small transitional zonebetween them. a. Inner Zone – the fibers are at right angles to the bony surface. b. Outer Zone – they run parallel to the bony surface. As in fibrous covering of the mandibular condyle, a variable number of chondrocytes arefound in the tissue on the temporal surface. In adults the deepest layer shows a thin s=zone ofcalcification. There is no continuous cellular lining on the free surface of the fibrocartilage. Onlyisolated fibrolast are situated on the suface itself. They are characterized by the formation oflong, flat cytoplasmic processes.
Mandibular Condyle It is composed of a fibrous layer of tissue that is of fairly even thickness. Its superficiallayers consist of a network of strong collagenous fibers. Chondrocytes may be present and theyhave a tendency to increase in number with age. They can be recognized by their thin capsule,which stains heavily with basic dyes. The deepest layer of the fibrocartilage is rich in chondroidcells as long as growing hyaline cartilage is present in the condyle. It contains only a few thincollagenous fibers. In this zone the appositional growth of the hyaline cartilage of the condyletakes place during the period of growth. Unlike the articulating surfaces in most joints of the body, the mandibular condyle is notcovered by naked hyaline cartilage. Instead, its articulating cartilage surface is covered by a thinlayer of poorly vascularized dense connective tissue with few fibroblasts. Collagen type I is themajor constituent found in this outer layer. However, during its development phase, the growing condyle is covered by aperichondrium and its bulk is made up of typical hyaline cartilage. A similar fibrous layer coversthe surface of the temporomandibular fossa and articular tubercle. The inner region of thisfibrous layer retains progenitor cells that give rise to prechondrocytes.Function of Mandibular Condyle: 1. Adapts the shifting vector of force, such as in chewing. 2. Undergo changes, some of which are related to changes in mandibular function and occlusion, since throughout life, the shape of the condyle undergo changes.III. Synovial Tissue A synovial membrane covers the inner surface of the joint capsule. The synovial membrane does not cover the articulating surfaces and the corresponding parts of the articulating disk. The synovial membrane is neither an epithelial lining nor an actual membrane; rather it is composed entirely of connective tissue rich in collagen V. The synovial membrane is well vascularized with numerous fenestrated capillaries. Histopathologic studies indicate that there is substantial variation in the morphology of the synovial lining of the normal TMJ, and that synovial inflammation of the TMJ tends to be less severe than that arising in other joints.
IV. Ligaments 1. Lateral Temporomandibular Ligament - Strengthens the lateral aspect of the capsule, and its fibers run downward and backward from the tubercle on the root of the zygoma to the lateral surface of the neck of the mandible. This ligament limits the movement of the mandible in a posterior direction and thus protects the external auditory meatus. 2. Sphenoparietal Ligament - Lies on the medial side of the joint. It is thin band that is attached above to the spine of the sphenoid bone and below to the lingual of the mandibular foramen. It represents the remains of the first pharyngeal arch in this region. 3. Stylomandibular ligament - Lies behind and medial to the joint and some distance from it. It is merely a band of thickened deep cervical fascia that extends from the apex of the styloid process to the angle of the mandible.DEVELOPMENT OF THE TMJ The development of the TMJ involves the following structures: Mandible Glenoid fossa Condyle Articular disc Upper joint cavity and Lower joint cavity At 12 weeks of the gestation, the TMJ begins to develop which is marked by theappearance of two distinct regions of mesenchymal condensation: the temporal/glenoidblastema and condylar blastema where the glenoid fossa and condyle arise respectively.
Mandible The Meckel’s cartilage is the one responsible for the skeletal support for thedevelopment of the mandible or the lower jaw that begins from 6 th to 7th week. It extends fromthe midline that goes laterally and posteriorly.Formation of the Glenoid Fossa Between 10th to 11th week, bone formation in the temporal blastema had begun andcontinues anteriorly while the condylar blastema remains undifferentiated and in betweenthem is a gap.Formation of the Condyle The condyle, at first is cartilaginous, develops between the 10th and 11th weeks from theaccumulation of mesenchymal cells called condylar blastema that is lateral to Meckels cartilage.Enchondral ossification progresses apically, creating a bony fusion with the body of the mandible.Immediately above the condylar blastema appears a cleft which becomes the lower joint cavityand then as the condylar blastema differentiates into a cartilage called condylar cartilage. Asecond cleft then appears in relation to the ossification of the temporal bone for the glenoidfossa which becomes the upper joint cavity.Formation of the Upper and Lower Joint Cavity The lower joint space appears first at about the 10th week, but later the upper jointspace overtakes it in its development. The upper joint space appears after about the 12th week and spreads posteriorly andmedially over Meckels cartilage with its contour corresponding to that of the future fossa. After13th week the lower joint space is already well formed as the upper joint space continues totake shape. From its beginning, the upper joint space has fewer individual islands of space andgrows more rapidly than the lower joint space. After 14th week both joint spaces are completelyformed.Formation of the Articular Disc With the formation of these two clefts is the formation of the primitive articular disc.The articular disk can first be identified after 7.5 weeks in utero as a horizontal concentration
of mesenchymal cells. Between weeks 19 and 20 its typical fibrocartilaginous structure is alreadyevident.MUSCLES OF MASTICATION The Masseter is a thick, somewhat quadrilateral muscle, consisting of two portions,superficial and deep. The superficial portion, the larger, arises by a thick, tendinousaponeurosis from the zygomatic process of the maxilla, and from the anterior two-thirds of thelower border of the zygomatic arch; its fibers pass downward and backward, to be inserted intothe angle and lower half of the lateral surface of the ramus of the mandible. The deepportion is much smaller, and more muscular in texture; it arises from the posterior third of thelower border and from the whole of the medial surface of the zygomatic arch; its fibers passdownward and forward, to be inserted into the upper half of the ramus and the lateral surfaceof the coronoid process of the mandible. The deep portion of the muscle is partly concealed, infront, by the superficial portion; behind, it is covered by the parotid gland. The fibers of the twoportions are continuous at their insertion. The Temporalis (Temporal muscle) is a broad, radiating muscle, situated at the side ofthe head. It arises from the whole of the temporal fossa (except that portion of it which isformed by the zygomatic bone) and from the deep surface of the temporal fascia. Its fibersconverge as they descend, and end in a tendon, which passes deep to the zygomatic arch and isinserted into the medial surface, apex, and anterior border of the coronoid process, and theanterior border of the ramus of the mandible nearly as far forward as the last molar tooth. The Pterygoideus externus (External pterygoid muscle/Lateral pterygoid muscle) is ashort, thick muscle, somewhat conical in form, which extends almost horizontally between theinfratemporal fossa and the condyle of the mandible. It arises by two heads; an upper from thelower part of the lateral surface of the great wing of the sphenoid and from the infratemporalcrest; a lower from the lateral surface of the lateral pterygoid plate. Its fibers pass horizontallybackward and lateralward, to be inserted into a depression in front of the neck of the condyleof the mandible, and into the front margin of the articular disk of the temporomandibulararticulation.
The Pterygoideus internus (Internal pterygoid muscle/Medial pterygoid muscle) is athick, quadrilateral muscle. It arises from the medial surface of the lateral pterygoid plate andthe grooved surface of the pyramidal process of the palatine bone; it has a second slip of originfrom the lateral surfaces of the pyramidal process of the palatine and tuberosity of the maxilla.Its fibers pass downward, lateralward, and backward, and are inserted, by a strong tendinouslamina, into the lower and back part of the medial surface of the ramus and angle of themandible, as high as the mandibular foramen. Nerves.—The muscles of mastication are supplied by the mandibular nerve. Actions.—The Temporalis, Masseter, and Pterygoideus internus raise the mandibleagainst the maxillæ with great force. The Pterygoideus externus assists in opening the mouth,but its main action is to draw forward the condyle and articular disk so that the mandible isprotruded and the inferior incisors projected in front of the upper; in this action it is assisted bythe Pterygoideus internus. The mandible is retracted by the posterior fibers of the Temporalis.If the Pterygoidei internus and externus of one side act, the corresponding side of the mandibleis drawn forward while the opposite condyle remains comparatively fixed, and side-to-sidemovements. Such as occur during the trituration of food, take place.Table 1. Muscles of MasticationMuscle Origin Insertion Nerve Supply Action Lateral surface ElevatesMasseter Zygomatic arch ramus of mandible to mandible occlude teeth Anterior and superior fibers Coronoid Floor of elevateTemporalis process of temporal fossa Mandibular mandible: mandible division of posterior fibers trigeminal nerve retract mandible Greater wing of (V3)Lateral Neck of Pulls neck of sphenoidpterygoid mandible mandible Lateral(two heads) Articular disc forward pterygoid plate Tuberosity ofMedial Medial surface maxilla Elevatespterygoid of angle of Lateral mandible(two heads) mandible pterygoid plate
BIOMECHANICSMANDIBULAR POSITIONS 1. Postural Position of Mandible Muscles of mastication are relaxed Teeth are not in contact in mastication, swallowing or speech Lips at rest and jaws apart Free Way Space or Vertical Dimension of Rest • Space between mandibular and maxillary teeth when mandible is in postural position. Average space = .3 – .7 mm 2. Centric Occlusal Relation Position of the mandible with maximum intercuspation of teeth. 3. Right Lateral Occlusal Relation Points to the right of centric relation.
4. Left Lateral Occlusal Relation Points to the left of centric relation. 5. Protrusive Occlusal Relation Anterior upper and lower incisors are into an edge-to-edge contact.MANDIBULAR MOVEMENTS It is named after the direction of movement of the mandible takes as it moves from theintercuspal position. 1. Right Lateral Movement Jaws move to the right bringing the teeth together in a right lateral occlusal relation.
2. Left Lateral Movement Jaws move to the left bringing the teeth in a left lateral occlusal relation. 3. Protrusive Movement Mandible depressed then moves forward bringing a protrussive occlusal relation. 4. Retrusive Movement Both condyles are upward and back into the mandible fossa. Teeth are in a non-functional occlusal relation. 5. Bennett Movement Movement of the mandible to the right or left during mastication.CLASSIFICATION OF MANDIBULAR MOVEMENTS: 1. Border Movements Limits of mandible movement in any direction. 2. Intraborder Movements Any mandibular movement within the perimeter of border movements and is chiefly associated with free movements. 3. Contact Movements Movements which the mandibular and maxillary teeth maintain contact. 4. Free Movements Movement wherein the reference point failed to reach its border and the teeth do not come into contact.ENVELOPE OF MANDIBULAR MOTION (by Posselt)
Mandible follows a curved trajectory in opening and closing. In closing: Molars - horizontal path; Anterior teeth - vertical movement Curvature of dental arches enables occlusal balance throughout mandibular movementrange.CLINICAL CONSIDERATIONS (TMJ)1. Bruxism - A condition where in you unconsciously grind, gnash or clench your teeth during day or night time. - Over a long period of time, it may tend to causes tooth wear and breakage, disorders of the jaw (pain and limited movement) and headache. - This is considered parafunctions of the adults and are thought to result from physiological stress with or without occlusal interference. - In children, it has alleged associations with allergies, asthma, digestive upsets, nervousness. Bruxism In primary dentition is a special problem which might termed a “functional malocclusion” and not necessarily pathogenic. Genetic factors and psychosomatic symptoms is correlated with bruxism in children.
- This can be artificially induced by sustained tooth clenching like mouth guards/night guard, Mandibular Advancement Devices.2. Arthritis - The synovial fluid is reduced in amount and becomes thicker in viscosity. This result inpain and swelling in joint capsule. Sometimes very small cyst also appears in condylar heads.3. Fractures - The thinness of the bone in the articular fossa is responsible for fractures if the Mandibular head is driven into the fossa by heavy blow. - Patients with fractures of the neck of the condyle usually present history of severe trauma to the symphysis or directly to the joint. Symptoms are swelling, altered occlusion and pain in the area of the joint. - when the dentist places a finger in the external auditory meatus while the patient moves his mandible, no condylar movement is felt.4. Structural Changes - The finer structure of the bone and its fibrocartilaginous covering depends upon mechanical influences. A change in force or direction of stress, occurring especially after loss of posterior teeth, may cause structural changes. This frequently occurs after the loss o posterior teeth. The important change is separation between the collagen bundles (thin, fragile, and separated from each other). This results in the pain at the TMJ.5. Disharmony in the relation of teeth and the Temporomandibular joint. - Clinical symptoms: pain in the region of joint and pain radiating to the temporal, infraorbital, supraorbital, and postauricular areas, which may be of such severity as to produce trismus. The joint has palpable irregularities and produces popping and clicking noises.6. Myofacial Pain Dysfunction (MPD) Syndrome characterized by a. pain (dull ache in ear or preauricular area which may radiate to the angle of mandible
b. masticatory muscle tenderness, most frequently, the lateral pterygoid, and then, the temporalis, medial pterygoid, and masseter. c. limited opening of mandible (<37mm) d. joint sounds (clicking or popping noise in the TMJ) These symptoms are seen more often in females. Hypersensitivity and spasm of themuscles of mastication account for many of the symptoms. Since the condition may be relatedto stress, treatment should be as conservative as possible.7. Luxation or Dislocation of Temporomandibular Joint - the Dislocation of Temporomandibular Joint is a forward displacement of the head of condyle in front of the eminence. (during wide opening of mouth like in yawning) - *very careful external manipulation of mandible in downward and backward direction for extrusion of mandible at proper place* happens mostly in aged persons and mostly in females because of (a) wearing and resorption of articular eminence (b) reducing muscle tone with the advancing age. Treatment: injection of various sclerosing solutions are given in TMJ capsular lgaments to tone them up with variable success rate. - Treatment of luxation consists of reduction and immobilization for a week, using interdental arch wires and rubber bands, to permit tissue repair. For acute dislocation, reduction and immobilization for 2 to 3 weeks to prevent secondary hemorrhage and to permit tissue repair.8. Ankylosis - is immobility and consolidation of joint and its most frequent cause is injury to the joint or infection in or around the joint. It may occur due to (a) intrauterine fetal abnormality (b) forcep deliveries (c) malunion of condylar fractures (d) metastatic malignancies (e) rheumatoid arthritis (f) inflammation of joint from infection in ear like otitis media - two types:
a. Fibrous ankylosis – also called partial ankylosis, is the result of fibrotic changes in the joint following hemorrhage caused by external trauma. A slight space can be seen between the condyle and the fossa in the roentgenogram. b. Bony ankylosis – is generally the result of infectious or suppurative disease. Complete bony union between the condyle and the fossa can be seen in the roentgenogram.9. Aplasia of condyle - Failure of development of Mandibular condyle may occur unilaterally or bilaterally. Inunilateral condylar aplasia, there is obvious facial asymmetry toward the affected side.10. Hypoplasia of Mandibular Condyle - underdeveloped or defective formation of condyle, which may be congenital oracquired because of reasons like forceps deliveries in newborns and damage following radiationtherapy of jaws.11. Hyperplasia of Mandibular Condyle - Chronic mild inflammation may cause hyperplasia of condyle unilaterally causingunilateral elongation of face and deviation toward the normal side.
BibliographyJulian B. Woelfel and Rickne C. Scheid : Dental Anatomy: Its Relevance to Dentistry, 5th EditionBertram S. Kraus : Kraus Dental Anatomy and OcclusionP.R. Grant : Oral Cells and TissueOrban : Orban’s Oral Histology and EmbryologyNathan Allen Shore : Temporomandibular Joint Dysfunction & Occlasal Equilibrium 2nd EditionHenry Gray : Gray’s AnatomyRichard Snell : Clinical Anatomy by Regions, 8th EditionRobert E. Moyers : Handbook of OrthodonticsTen Cate, A.R. : Oral Histology- Development, Structure, and Function, 4th Edition