PULP PROTECTION

                        

    This is a step in adapting the preparation for receiving the final restoration material.

     Sound dentin is the best barrier between a restorative material and pulp. So conservation of all sound dentin possible during cavity preparation should be beneficial.

     When the thickness of remaining dentin is minimal, heat generated by injudicious cutting can result in pulpal burn lesion, abscess formation or pulpal necrosis. So water or air spray coolant should be used with high speed rotary instrument. The remaining dentin thickness is measured by using dentinometer.

     Cutting of previously unexposed dentinal tubules will result in degeneration and death of affected primary odontoblast and their processes resulting in formation of dead tracts.

Other pulpal irritants are:

1.      Some ingredients of various materials

2.      Thermal changes conducted through restorative materials

3.      Forces transmitted through materials to dentin

4.      Galvanic shock

5.      Injuries of noxious products and bacteria through microleakage.

To protect the pulp from these kinds of irritation cavity liners, varnishes, cavity liner suspension, intermediary bases, cement bases, etc. are used.

                                               CAVITY LINER:

              Liners are volatile or aqueous suspension or dispersion of Zinc oxide or calcium hydroxide that can be applied to a tooth surface in a relatively thin film. A few microns to about a millimeter in thickness.

Liners Provide:

1. A barrier that protect the dentin from noxious agents.
2. Initial electrical insulator.
3. Some thermal protection.

           A traditional liner is used to medicate the pulp when suspected trauma has occurred. The desired pulpal effects include sedation stimulation, later resulting in reparative dentin formation. If the removal of infected dentin does not extend deeper than 1-2mm from initially prepared axial or pulpal wall usually no liner is indicated. If the excavation extends into or closes pulpal tissue, Calcium hydroxide, Zinc oxide Eugenol liner is used. There liners in thickness of 0.5mm or greater have adequate strength to resist condensation forces of amalgam and provide protection against short term thermal changes. Then should be approximately 2mm of bulk between pulp and metallic restorative materials.

          The ability of calcium hydroxide to stimulate formation of reparative dentin when it is in contact with pulpal tissue makes it is the material of choice in very deep excavations and known pulpal exposures.

                           CAVITY VARNISHES  

           There is no solution liner derived from natural gums, copal synthetic resins or rosin. When varnishes are applied to prepared tooth surface the solvent quickly evaporates leaving thin film of resinous materials (micro thickness). Two goals of varnish application are mandatory for complete seal. These are insoluble in oral fluids. These are applied to cavity wall using a small cotton pledge. Tooth varnishes usually applied just before the insertion of amalgam or cementation of cast gold restoration. These are the only material required in shallow preparations. These helps to prevent microleakage and reduce post operative sensitivity. These help to reduce pulpal irritation from leaking cement. They can be applied to enamel portion of the preparation. Tooth varnishes are not used under composite because solvent in the varnish reacts with resin component of composite and adversely affect the polymerization reaction. The free monomer of the resin can dissolve the varnish film. Varnishes will hamper the fluoride releasing property of glass ionomer cement. So they are not used under GIC also.

                                      CAVITY LINER SUSPENSIONS   

       These are suspensions of calcium hydroxide, zinc oxide which are particularly used under tooth colored restorative material. The film deposited by these materials is thicker. They will dissolve & disintegrate in oral fluids, thus allowing severe marginal leakage if they are brought in to cavosurface. The whitish color also affects the aesthetic value of restoration. So they are confined to dentinal wall only.

                                        

                                       INTERMEDIARY BASES.

          There is no clear distinction between intermediary bases & cavity liners. Two forms of intermediary bases used are calcium hydroxide &modified zinc oxide eugenol.

   Zinc oxide eugenol has topical anesthetic properties termed as obtudant effect. When a history of discomfort is found, zinc oxide intermediary base can be used.

    They are contraindicated under composite because they will affect the polymerization reaction. Calcium intermediary bases are used as indirect pulp capping agents, protective chemical barrier under filled &unfilled resins. Calcium hydroxide has no otundant properties.

                                         CEMENT    BASES

Cement bases are relatively thick materials placed under the restorative material which will provide chemical &thermal insulation. They should be capable of providing support to the restoration that is subjected to occlusal function. Four types of base material used are Zinc phosphate, Reinforced Zinc oxide eugenol, Glass ionomer cement and Zinc polycarboxylate.

The level to which the base is built should never compromise the desired tooth preparation resulting in inadequate restorative material thickness. Since cement base materials are subjected to stress during insertion of restorative material and also they are indirectly supportive of masticatory functions, they also require their own specific retention in the prepared cavity. Retentive grooves are made using round burs directly laterally in the dentin.

   In case of pin retained restorations, cemented pins are used for pulpal protection.

  These are different methods of pulpal protection.

Regardless of the material used protecting the pulp appropriately is mandatory for the successful restoration of the teeth

      

 REFERENCES-

                                  •Sturdevant’s Art&Science of Operative Dentistry

                                  •Principles&Practice of Operative Dentistry-Gerald T Charbeneau

                                  •Textbook of Operative Dentistry-Vimal Sikri

                                  •Textbook of Operative Dentistry-Satish Chandra

                                                               

Patient Complains of sensitive teeth on biting after Restoration. What to do?

A Pressure sensitive teeth after filling is an annoying condition. Many of us have such cases.Now lets see why this occurs and how to solve it.There are many causes for it lets see it one by one and consider the treatments
NOTE- In this article we will consider the causes of sensitive teeth on biting only (Pressure Sensitive teeth )  and not for Hot and cold sensitive or continuous pain after filling.

Cause 1. Composite restoration cases- if there is a bubble entrapment at the bonding interface of composite and dentin it will cause sensitivity. This occurs because the bubble shrinks during biting and applies pressure.
Solution-Remove the restoration and replace it with corrected one,use Single bond agents which does not require separate etching and boning.

Cause2. Deep caries.Dentin is too thin to protect the underlying pulp.
Solution - After removal of caries apply a nice layer of Calcium Hydrroxide/Dycal and cover it with temporary restoration. Ask the patient not to bite heavy on the particular tooth and recall after 4 weeks. Ask about the symptoms.If not resolved then let it be there for 4 more weeks.If resolved then replace the temporary restoration with permanent one.

Cause 3. Pulp hyperemia or thermal trauma during cavity preparation.
Solution- Remove the restoration and replace it with ZOE filling ,Relieve the tooth from occlusion, Start any NSAID for three days Recall after 3 weeks ask about symptoms, if relieved then replace the ZOE with permanent restoration.
[Additional]-Check your bur and replace it if its worn out, check for water spray of your handpiece it should be directed on the bur, Don't apply pressure will tooth preparation.

Cause 4. High point on the restoration.
Solution- Take an Articulating paper,Check for the high point and clear them. Recall after 5 days. If patient still have pain relieve the tooth from occlusion and start any NSAID.  

Gingival Depigmentation Technique using Bur Abrasion {Step Wise}

When we talk about gingival depigmentation it all comes to "Smile". Most of your patients will come to you with a complain of blackish gums.They will say "My gums are black and they don't look good please do some treatment"  people are concerned about their smile. So what to do ? how to reduce the black discoloration of the gums?  
There are many techniques - Laser, scalpel surgery,Bur abrasion, epithelial excision, electrocautery, cryotherapy.

• Here we will discuss a technique which can be performed in a regular dental set up and does not require higher equipment,You don't have to be a Periodontist to do this surgery you can do this if you are a dental graduate,Bur abrasion is relatively easy and safe and it can be easily repeated if there is any residual pigmented area. 

Before Treatment

After Bur Abrasion

Initial Healing

The Process-


Step 1- 

• When patient arrives and show concern about the blackish gums tell them this condition can be treated and you can reduce the blackish color of their gums, Show your confidence in treatment (remember patient buys confidence in you) tell them about benefits of improved looks and improved confidence.  
• If patient shows interest, inform them about the treatment procedure and possible results.Show them before and after photographs of your successful cases ( If you don't have photos then "right click & save" the pics given in this article and use them)
• Once patient gets ready for the treatment take proper medical and family history,Do all the necessary blood investigations and rule out any contraindications for surgery,
• Take written consent this is very important I ask all the young dentist to take written consent before any kind of surgery, this will be very helpful if you are subjected to malpractice claims. 

Step 2

• Materials used- Lignocaine with adrenaline in the ratio 1:100000 by weight. Gauze pieces, A high speed hand piece with round diamond bur, hand piece should be sterilized before the treatment and you should use a new bur not the bur you are using for endo or operative purpose.

Step 3

• [Prepare the patient] Surgery is usually required from premolar to premolar region of maxillary anterior. If patient wants the treatment for both arch then involve mandibular arch too.Now anesthetize the area with local infiltration.

Step 4

• Start Deepithelization by removing the epithelium of the gingiva with help of round diamond bur, just touch the revolving bur on the surface of pigmented gingiva and move the bur with feather light strokes, don't keep the bur at one place for long time it may result in thermal trauma and permanent harm to underlying tissue.
• There is no need of pressure in this procedure just touch the bur to superficial part of epithelium and remove it upto connective tissue care must be taken not to harm underlying periostium.   
• Use round bur of biggest size because small bur will produce small pits rather then surface abrasion. 
• Controle the bleeding and check for any pigmented area and remove it to prevent relaps. Epithelium should be removed upto connective tissue/"Lamina proprria".
• Bleeding Control- It can be done by applying pressure by a gauze piece on the denuded epithelium Soak the  gauze piece in Adrenaline containing Local anesthetic.
• Caution- Removal of gingival melanin pigmentation should be performed cautiously and the adjacent teeth should be protected, since inappropriate application may cause gingival recession, damage to underlying periosteum and bone, delayed wound healing, as well as loss of enamel.    

Step 5- 

• Apply a surgical dressing like 'Co -pack' for few days and prescribe Chlorhexidine mouthwash for 1 week.

Step 6 -

•  Recall after 1 weeks and check for the status and any healing problems. 

Some common hematological medical diseases encountered in dental clinics

• Hematological disorders-

1. Anaemia
2. Thalassaemia
3. Polycythemia Vera or Primary Polycythemia
4. Disseminated intravascular coagulation
5. Leukemia
6. Thrombocytopenia (quantitative disorder of platelets)
7. Thromboasthenia (qualitative disorder of platelets)
8. Haemophillia A/B
9. VWD
10. Liver disorders
11. Vitamin k deficiency 

• Anaemia-Hemoglobin level is below the normal range in a given individual on the basis of age and sex.
• Thalassaemia-Thalassemia  is an inherited blood disorder that causes your body to make less hemoglobin.There are two types of thalassaemia-Alpha(major/minor) ; Beta (major/minor).
• Polycythemia Vera-Increased production of all type of blood cells-R.B.C,W.B.C and platelets.This makes blood thick.
• DIC- In DIC, the body's natural ability to regulate blood clotting does not function properly. This causes the blood's clotting cells (platelets) to clump together and clog small blood vessels throughout the body. This excessive clotting damages organs, destroys blood cells, and depletes the supply of platelets and other clotting factors so that the blood is no longer able to clot normally. This often causes widespread bleeding, both internally and externally.
• Leukemia-When you have leukemia, the bone marrow starts to make a lot of abnormal white blood cells, called leukemia cells. They don't do the work of normal white blood cells, they grow faster than normal cells, and they don't stop growing when they should.Over time, leukemia cells can crowd out the normal blood cells. This can lead to serious problems such as anemia, bleeding, and infections. Leukemia cells can also spread to the lymph nodes or other organs and cause swelling or pain.
• Thrombocytopenia-Decreased platelets count.
• Thromboasthenia-Normal platelet count but still there is defective haemostasis as in case of drugs intake like aspirin;VWF;splenomegaly.
• Haemophillia-Deficiency of clotting factors.(VIII in haemophillia A & IX in haemophillia B)
• VWD-There is decrease in von willibrand factor in blood.This factor is must for the maintenance of factor VIII & also for platelet aggregation.
• Liver disorders-Liver is must for the production of clotting factors.so any insufficiency can affect the normal clotting process.Thrombocytopenia can be seen in cirrhosis.
• Some common blood test-

1. Bleeding time (B.T) - Normal B.T=2 to 6 minute Increased in DIC,Leukemia,Thrombocytopenia,Thromboasthenia,VWF
2. Clotting Time (C.T)- Normal C.T=5 to 15 minute Increased in Haemophillia,VWF,DIC
3. PT-monitors extrinsic pathway (amount of factor III,VII,V) Normal value 10-12 sec.
4. PTT-monitors intrinsic pathway(VIII,IX,XI,XII) normal values 25-38 sec.
5. C.B.C- Normal R.B.C- 4-6 million/mm cube of blood                                                                          Normal W.B.C- 4000-11000/mm cube of blood                                                                         Normal Platelet count- 150000-400000/mm cube of blood                                                                Normal Hb- Female 14gm/dl  male 16 gm/dl                                                                           Haematocrit-The hematocrit measures how much space in the blood is occupied by red blood cells. It is useful when evaluating a person for anemia. Males-40%-54% Females-37%-47%                                                     WBC differential- Neutrophil- 40-75%  Lymphocyte- 15-45%  Monocytes- 1-10%  Eosinophils- 1-6% Basophils-0 - 2%

• Neutrophil- Normal value 1500-7000 cells/mm cube.Increases in bacterial infections.Decreases in Viral infection.                                                                                                                                           1000-1500cells/mm cube = Mild chances of infection chances

          500-1000 cells/mm cube=Moderate chances of infection

          Less than 500 cells/mm cube=severe chances of infection.                                                                                                In case of mild or moderate neutropenia before every dental procedure make patient use non alcoholic mouthwash gargle.Administer systemic antibiotics even after the treatment.In case of severe neutropenia neutrophils can be administered.

• Lymphocyte count increases in viral infections.
• Eosinophils increase in allergies,parasitic infections
• Normal platelet count-150000-400000/mm cu

When platelet count goes below 150000 than its called as throbocytopenia.For major surgeries count should be 100000/mm cube.For oral and periodontical surgeries normally platelet should be 75000/mm cube.For minor dental procedures paltelet count should be about 50000/mm cube.Spontaneous bleeding occurs when count is below 20000/mm cube.Such cases need platelet rich plasma.

Idiopathic thrombocytopenia-auto antibodies against platelets cells

• Anemia- 

Iron deficiency anemia,Thalesemia: MCV;MCH;Hematocrit;Hb all decreases.

Folic acid deficiency/vit.B12 anemia:MCV;MCH increases but Hb;Haematocrit decreases.

Aplastic anemia:MCV and MCH all are normal.Hb & hameatocrit decreases.

Differ routine dental t/m in case of severe anemia(Hb less than 50%)

• Drugs which affect platelets-

Quality-Aspirin,indomethcin,phenylbutazone,sulphinpyrazone (NSAIDS COX inhibitors)

Quantity-Quinine,sulfonamide drugs(Thiazide diuretics,sulfonylurease),rifampicin,cytotoxic drugs(chemotherapy)

• Immediate bleeding-Beyond 24 hours of operation or surgery.Defect in platelets.

          Delayed bleeding-after 4 or 10 days of operation.Defect in clotting factors.

• Thalassaemia-If there are repeated blood transfusions, it’s possible for body to get too much iron. This can damage organs, especially the liver. Make sure to avoid vitamins that contain iron, and don't take extra vitamin C, which can increase how much iron absorbed from food. If there is too much iron, you can give chelation therapy. 

                     

ANATOMY OF HEAD & NECK

X-Ray TUBE

• An X ray tube is composed of a cathode and an anode situated within an evacuated(vacuum) glass envelope.
• Cathode- Negative charged focusing cup having tungsten filament
• Anode-Copper stem having tungsten target acting as focal spot.Its positively charged.
• Cathode releases electrons towards anode, which is directly proportional to the temperature of the tungsten filament of cathode.
• Current is passed through the cathode tungsten filament to heat it up,this heating produces production of electrons from the tungsten filament.The tube voltage difference between the cathode and anode causes movement of electrons from cathode to anode with a kinetic energy.This electrons hit the anode at focal spot and lose there kinetic energy which forms the X ray photons.
• Focal Spot-Its the area of anode on which electrons from cathode collide.Area of focal spot size is inversely proportional to the image sharpness.To increase the image sharpness therefore area of focal spot should be decreased,But if it is done than area of heat dissipation also decreases.So to overcome this focal spot is bent to an angle of 20 degree due to this actual focal spot size becomes 1mm* 3mm (increases area for heat dissipation) & effective focal spot size becomes 1mm*1mm (increases sharpness) .
• When electrons in the tube flows from cathode to anode than there is a flow of current in side tube called as tube current.
• But to make electrons move from cathode to anode there need to be a voltage difference between anode and cathode,this voltage difference across anode & cathode is called as tube voltage.Tube voltage is amplified by high voltage transformer i.e. 110 V of outside voltage is converted to 60 to100 KV,this causes electron kinetic energy raised up to 60 to 100 Kev.
• Both the tube current and tube voltage can be changed from outside.
• Timer-The electronic timer controls the length of time that high voltage is applied to the tube and therefore the time during which tube current flows & X rays are produced.
• BREMSSTRAHLUNG RADIATION-This radiation is produced when a fast moving electron head on collides with the nucleus of tungsten atom and losses its all kinetic energy (equivalent to the potential difference  between cathode and anode) to produce a photon of maximum energy.More frequently some electrons don't collide target atom head on,rather high speed electrons have a near or wide misses with atomic nuclei. During deflection these electrons loose some of there kinetic energy that is released as photon.These photons produced have energy below that the one produced by head on collision.Thus Bremsstrahlung interaction produces a continuous spectrum of energy.
• Reasons for continuous spectrum-

1. Continuously varying Voltage difference between the target and filament(Half wave rectification).
2. Bombarding electron passes target nucleus at varying distances and thus releasing photon of different energy.
3. Many electrons participate in many bremsstrahlung interactions in target before loosing all energy.Electrons with higher kinetic energy produces more number of photons too.

• CHARACTERISTIC RADIATION-These radiations are produced when electron strike inner orbital electron of target atom.This knock out the target atom electron and at the same time electron from outer orbit jumps to inner orbit after releasing photon,which forms the Characteristic radiation.
• FACTORS CONTROLLING X RAY BEAM-

1. Exposure time-If exposure time is increased than current passed through cathode is more therefore electron produced are more from the filament which produces more photons on collisions with anode.When exposure time is doubled,number of photons produced are also doubled,but the range of photons energy remain unchanged.
2. Tube Current-As the current passing through the cathode is increased,the heat produced also increases that produces more electrons(tube current),which in turn increases the number of photon produced on collision to anode.Tube current is directly proportional to the number of photons produced,keeping other parameter constant .The quantity of radiations produced is equivalent to the product of tube current and exposure time.as far as this product remains constant number of electrons produced will be constant at a given tube voltage.
3. Tube Voltage-As the tube voltage is increased the number of photons produced and the energy of photons produced,both increases.The electrons emitted from cathode move with more kinetic energy when higher tube voltage is used.Thus more photons are produced by bremsstrahlung radiations.

• FILTRATION-Filtration is a process of preferentially removing some low energy photons from the x ray beam,which only lead to undue patient exposure. Filtration is done by using aluminium layer is called as extrinsic filtration.Inherent filtration is provided by insulating oil.Total filtration should be equal to 1.5mm of aluminium layer.
• COLLIMATION-Collimation is a metallic barrier with an aperture in middle used to reduce the size of X ray beam and thereby reducing the patient exposure.When patient gets exposed to x ray than 10% xray reaches the film rest is absorbed by the oral tissues and after absorption they are scattered back.These scattered photons affect the quality of X ray.Thus by collimation production of scattered photons also get reduced,thereby increasing the quality of X ray.Lead is used for collimation.

MUSCLES OF TONGUE

• DIVIDED INTO TWO TYPES OF MUSCLES- EXTRINSIC & INTRINSIC
• EXTRINSIC MUSCLES - 

1. GENIOGLOSSUS- origin: Genial tubercle of mandible; insertion: Tip and dorsum of tongue & hyoid bone.
2. HYOGLOSSUS-origin: Greater cornua of hyoid bone; insertion: Side of tongue 
3. STYLOGLOSSUS- origin: styloid process; insertion: Side of tongue
4. PALATOGLOSSUS-origin: palatine aponeurosis; insertion: side of the tongue at the junction of tongue and pharynx.

• INTRINSIC MUSCLES-

1. SUPERIOR LONGITUDNAL
2. INFERIOR LONGITUDNAL
3. TRANSVERSE
4. VERTICAL

• NERVE SUPPLY OF TONGUE-

1. SENSORY NERVE SUPPLY- Lingual nerve branch of mandibular nerve(general nerve for sensation) & chorda tympani nerve branch of facial nerve(Taste sensation except circumvallate papillae) supply anterior two third of tongue.Glossopharyngeal nerve supplies sensory & taste  innervation to posterior one third of tongue including circumvallate papillae.Laryngeal branch of Vagus nerve supply most posterior part of tongue
2. MOTOR NERVE SUPPLY-Hypoglossal nerve to all muscles except palatoglossus which is supplied by cranial part of accessory nerve.

• PAPILLAE- A small, round or cone-shaped bump on the surface of the tongue. There are several types of papillae in the mouth, and all but one type containtaste buds.
  
  Fungiform - taste bud-containing papillae located on the front two-thirds of the tongue. They can be seen as red bumps (the bumps that stand out in contrast to the pinkness of the rest of your tongue); under magnification, they look a bit like mushrooms (fungi).
  Circumvallate - taste bud-containing papillae toward the very back of the tongue; they are placed in an inverted “V.” It can be very hard to see your own, but it is fairly easy to see these in another person, especially if you use a flashlight.
  Foliate - taste bud-containing papillae located very far back on the sides of the tongue; they look like a series of folds or lines and can be very difficult to see.
  Filiform - papillae that do not contain taste buds. They cover the surface of the tongue in great abundance and are largely responsible for the texture of the tongue. The only purpose it serves in tasting is that it can help to hold taste compounds on the tongue, increasing the chance that the taste compound will interact with a taste receptor cell.

The Suprahyoid Muscles

• This group of muscles is located superior to the hyoid bone and connects to this bone and the skull.
• This group includes the mylohyoid, geniohyoid, stylohyoid and digastric muscles.

The Mylohyoid Muscles 

• These are thin, flat triangular muscles that form a sling inferior to the tongue.
• They form the floor of the mouth.
• Role of these muscles in grinding the food in the mouth.

• Superior attachment: mylohyoid line of mandible.
• Inferior attachment: raphe and body of hyoid bone.
• Innervation: mylohyoid nerve, a branch of the inferior alveolar nerve.

• It elevates the hyoid bone, floor of the mouth and the tongue during swallowing and speaking.

Geniohyoid Muscles 

• These are short narrow muscles that contact each other in the median plane.
• They are located superior to the mylohyoid muscles, where they reinforce the floor of the mouth.

• Superior attachment: inferior mental spine of mandible.
• Inferior attachment: body of hyoid bone.
• Innervation: C1 via the hypoglossal nerve (CN XII).

• It pulls the hyoid bone anterosuperiorly, and shortens the floor of the mouth and widens the pharynx.

The Stylohyoid Muscles 

• These muscles form a small slip on each side, which is nearly parallel to the posterior belly of the digastric muscle.

• Superior attachment: styloid process of the temporal bone.
• Inferior attachment: body of hyoid bone.
• Innervation: Stylohyoid branch of facial nerve (CN VII).

• It elevates and retracts the hyoid bone, thereby elongating the floor of the mouth.

The Digastric Muscles 

• Each of the strap-like muscles has two bellies (G. gaster, belly) that descend toward the hyoid bone.
• They are joined by an intermediate tendon that is connected to the body and the greater horn of the hyoid bone by a strong loop or sling of fibrous connective tissue.
• This fibrous pulley allows the intermediate tendon to slide anteriorly and posteriorly.

• Superior attachment: anterior belly-digastric fossa of mandible, posterior belly-mastoid notch of temporal bone.
• Inferior attachment: intermediate tendon to body and greater horn of hyoid bone.
• Innervation: anterior belly-mylohyoid nerve, a branch of the inferior alveolar nerve, posterior belly-facial nerve (CN VII).

• It depresses the mandible and raises the hyoid bone. Also, it steadies the hyoid bone during swallowing and speaking.

 

Mylohyoid muscle alnwith lingual nerve and submandibular and sunlingual gland 

hyoid bone-

Location of the hyoid

Anterosuperior aspect

Right aspect

A small, U-shaped bone situated centrally in the upper part of the neck, beneath the mandible but above the larynx near the level of the third cervical vertebra. It can be felt by pressing one's finger into the crease where the chin becomes the neck. The hyoid bone consists of three separate parts – the body, and the left and right greater and lesser cornu (horns) – which fuse in early adulthood.

The function of the hyoid is to provide an anchor point for the muscles of the tongue and for those in the upper part of the front of the neck.

The hyoid is (uniquely in the vertebrate skeleton) not joined to any other bone but is suspended in position by muscles that connect it to the mandible, to the styloid process of each temporal bone at the base of the skull, to the thyroid cartilage, to the sternum, and to the scapula. The important muscles that are attached to the hyoid bone are shown in the lower two diagrams.

Mandible-anatomy

ASTRINGENTS

Astringents

Astringents cause contraction of tissues.They accomplish this by constricting small blood vessels,extracting water from tissue or precipitating protein.

Dentist can apply astringents to gingival tissues before taking impressions,placing ClassV or root surface restorations.They can alone be used  or in combination with retraction cords.

Aluminium Chloride::causes contraction or shrinking of tissues,making it useful in retracting gingival tissue.It also reduces secretions and minor hemorrhage.

Ferric Sulphate::is an effective and safe astringent and heamoststic for use in gingival retraction.

Aluminium sulphate::with other aluminium salts  is an effective and safe astringent and haemostatic for use in gingival retraction.

Aluminium Potassium sulphate::is not widely used, due to its limited properties.

SKULL ANATOMY

frontal view side view some more important sites- http://www.gwc.maricopa.edu/class/bio201/skull/antskul.htm http://www.csuchico.edu/anth/Module/skull.html Feature Location Description angle of jaw or mandible back of jaw the corner of the jaw where the mandible body turns upwards into the ramus aveolar process maxilla, root of teeth rugosities associated with tooth development condyle of mandible top of ramus of mandible a ball-like end to the ramus of the mandible that forms a hinge with the temporal bone coronal suture top of head between frontal and parietal cranial bones one of the major joints or sutures between the plates of the frontal and parietal cranial bones external acoustic meatus between ramus of mandible and mastoid process a hole in the temporal cranial bone allowing the passage of sound to enter the inner ear ethmoid bone eye cavity a cranial bone forming part of the eye cavity forehead boss or frontal tuberosity forehead a feature of the frontal bone that forms the "bumps" in the forehead above the eyebrows frontal bone top of face (forehead) and front top of head one of the major cranial bones that forms the forehead and front top of the head; roughly covers the frontal lobes of the brain glabella center of forehead an area in the center of the forehead, between the eyebrows, that assumes various shapes on different individuals lacrimal bone inner corner of eye socket a small bone forming a cavity for the tear gland lambdoid suture back of head suture or joint between the occipital and parietal cranial bones mandible or jaw bone lower part of jaw the lower jaw bone is the only skull bone that moves, i.e., during mastication, speech, and expression; carries the lower teeth maxilla upper part of jaw the two maxillae form the center of the face with many attaching muscles; carry the upper teeth; form part of the eye orbit; act like keystones into which the other facial bones fit mastoid process lower part of temporal bone, behind ramus of jaw built up area of the lower temporal bone where important neck muscles attach mental protuberance chin boss a feature of the mandible at the lower front part of the chin which underlies part of the chin boss mental tuberosities chin boss a dual bulbous formation of the mandible that underlies part of the chin boss nasal bone nose forms the upper part of the nose and nasal bridge; the lower part of the bridge is formed of cartilage nasal concha nasal cavity formations creating part of the nasal cavity nasal spine center of nose feature of maxilla facial bone at center of nose to which septum is attached occipital bone the lower rear of the head a major cranial bone at the lower back of the head; covers occipital lobe of the brain parietal bone top and side of head a major cranial bone that froms part of the top, back, and side of the head and roughly covers the parietal lobe of the brain ramus of mandible back part of the mandible the more vertical part of the mandible sphenoid bone temple and eye orbit area a cranial bone that forms part of the eye cavity squamosal suture side of head between parietal and temporal bones one of the major joints or sutures between the parietal and temporal cranial bones supraorbial foramen upper orbit of eye a hole in the frontal bone where nerves and blood vessels pass through; forms a notch in the orbit of the eye supraorbital process eyebrows a formation of the frontal bone above the orbit of the eye, under and above the eyebrows that affects the appearance of the eyebrows temporal bone side of the head, above the ear a cranial bone on the side of the head that roughly covers the temporal lobe of the brain; it extends down behind the ear towards the jaw temporal lines front part of temple and lower part of frontal bones lines in the frontal bone around the temple volmer nasal cavity a facial bone on the centerline of the nose that forms part of the nasal cavity zygomatic bone cheek the principal cheek bone; origin of zygomatic and other facial muscles zygomatic process bones bordering zygomatic bone the temporal and maxilla bones have areas next to the zygomatic bone

Above: Frontal View. Legend: 1- Mental tubercle. 2- Body of mandible. 3- Ramus of mandible. 4- Anterior nasal spine. 5- Canine fossa. 6- Infra-orbital foramen. 7- Zygomatic-facial foramen. 8- Orbital surface of maxilla. 9- Temporal fossa. 10- Lateral surface of ethmoid. 11- Superior orbital fissure. 12- Lacrimal bone and groove. 13- Optic foramen. 14- Ethmoidal foramina. 15- Temporal line. 16- Supra-orbital notch. 17- Glabella. 18- Frontal tuberosity. 19- Superciliary arch. 20- Parietal bone. 21- Naso-frontal suture. 22- Pterion. 23- Great wing of sphenoid. 24- Orbital surface of great wing of sphenoid. 25- Squamous part of temporal. 26- Left nasal bone. 27- Zygomatic bone. 28- Inferior orbital fissure. 27- Zygomatic bone. 28- Inferior orbital fissure. 29- Zygomatic arch. 30- Apertura piriformis, displaying nasal septum and infeior and middle concha. 31- Mastoid process. 32- Incisive fossa. 33- Angle of mandible. 34- Mental foramen. 35- Symphysis menti.

Above: Lateral View. Legend: 1- Mental foramen. 2- Body of the mandible. 3- Maxilla. 4- Ramus of the mandible. 5- Zygomatic arch. 6- Styloid process. 7- External acoustic meatus. 8- Mastoid process. 9- Asterion. 10- Superior nuchal line. 11- External occipital protuberance. 12- Lambdoid suture. 13- Occipital bone. 14- Lambda. 15- Obelion. 16- Parietal bone. 17- Lower temporal line. 18- Upper temporal line. 19- Squamous temporal. 20- Bregma. 21- Coronal suture. 22- Stephanion. 23- Frontal bone. 24- Pterion. 25- Temporal fossa. 26- Great wing of sphenoid. 27- Zygomatic bone. 28- Zygomatic-facial foramen. 29- Fossa sacci lacrimalis. 30- Nasal bone. 31- Infra-orbital foramen. 32- Anterior nasal spine.

Above: Basal View of the lower surface of the cranium (mandible is removed). Legend: 1- External Occipital Crest. 2- Superior nuchal line of the occipital bone. 3- Foramen magnum. 4- Occipital condyle. 5- Mastoid notch. 6- Mastoid process. 7- External acoustic meatus. 8- Styloid process. 9- Mandibular fossa. 10- Foramen spinosum. 11- Angular spine of the sphenoid. 12- Foramen ovale. 13- Lateral pterygoid lamina. 14- Hamulus of medial pterygoid lamina. 15- Vomer. 16- Posterior nasal spine. 17- Horzontal part of palate bone. 18- Palatine process of maxilla. 19- Incisive foramen. 20- Intermaxillary suture. 21- Greater palatine foramen. 22- Zygomatic process of maxilla. 23- Inferior orbital fissure. 24- Infra-temporal fossa. 25- Zygomatic arch. 26- Left choana. 27- Pterygoid fossa. 28- Scaphoid fossa. 29- Foramen lacerum. 30- Opening of osseous part of auditory tube. 31- Carotid canal. 32- Jugular fossa. 33- Stylo-mastoid foramen. 34- Jugular process of occipital bone. 35- Groove for occipital artery. 36- Mastoid foramen. 37- Canalis condyloideus. 38- Inferior nuchal line of occipital bone. 39- External occipital protuberance. Skull from above Temporal Bone Sphenoid bone