TYPES OF FINGER RESTS AND FULCRUM IN DENTISTRY FOR MAXILLARY AND MANDIBULAR TEETH

I would like to give brief about types of finger rest , types of fulcrum , Ideal wrist position and what is the importance of it in my blog

● Finger rest are very important part in dentistry for every treatment what ever we do which includes right from oral examination to other instruments like scaling, extraction and as well while performing root canal treatment which are usually a time taking without improper finger rest there will be excess strain on the dentist. To get least amount of stress and strain on the dentist while performing dental treatments for prolonged periods of time.

● Finger rest even important in proper retraction of cheek or tongue. Wrist position is also an important aspect to get proper finger rest and helps in reducing the strain on your hand. The fulcrum is a finger rest which is used to stabilize the working hand during periodontal treatment. A fulcrum gives us precise control over the amount of pressure being applied during each stroke.

TYPES OF FINGER RESTS FOR DENTAL SCALING FOR MAXILLA AND MANDIBLE

Conventional finger rest : The finger rest is established on the tooth surfaces immediately adjacent to working area

Cross arch finger rest : The finger rest is established on the tooth surfaces on the other side of the same arch which is being worked on

Opposite arch finger rest : The finger rest is established on the tooth surfaces on opposite arch. For example like finger rest is taken on the mandibular arch while working on the maxillary arch

Finger on finger rest or reinforced finger rest : The fourth finger of the operating hand rests on the index finger while the non operating hand on the lingual surfaces of maxillary posterior teeth are instrumented

Palm up extra oral fulcrum : The back of the finger rest on the right lateral aspect of mandible while the maxillary right posterior teeth are instrumented

Palm down extra oral fulcrum : The front surfaces of finger rest on left lateral aspect of mandible while the maxillary left posterior teeth are instrumented

TYPES OF FULCRUM IN DENTISTRY

Intra oral fulcrum : The stabilizing Finger is placed on the tooth close to the working area

Extra oral fulcrum : The fingers are placed on the chin or cheek outside mouth to get better stabilization

IDEAL WRIST POSITION IN DENTISTRY

Wrist position is also an important aspect to support ideal finger rest in order to decrease the stress on your wrist and tendons while working. These are 4 to 5 things which should be kept in mind to get an ideal wrist position

● Wrist should be aligned with lower arm

● Palm should be open and relaxed to decrease the strain on the wrist muscles

● Light pressure against the handle and with the thumb in oder to get good grip

● Index finger thumb held in rounded shape against the instrument being used

So, proper technique , finger rest , fulcrum and ideal wrist position are very essential which should be followed to give proper and stress free positioning for the dentist to work on.

Reference :- self notes

DENTAL PLAQUE

Plaque is a sticky film of bacteria that constantly forms on teeth. Bacteria in plaque produce acids after you eat or drink.These acids can destroy tooth enamel and cause cavities and gingivitis

Untreated plaque can harden into (tough to remove ) tartar. Proper oral hygiene, including daily brushing and flossing gets rid of plaque

SYMPTOMS AND CAUSES

● plaque forms when bacteria present in mouth mixes with sugary or starchy foods such as milk, juice, bread ,pasta and soft drinks. These bacteria release acids that breakdown carbohydrates in food and drinks.

● Symptoms : A fuzzy feeling on teeth is the top sign of plaque. Other indicators include halitosis( bad breath ) and red , swollen , tender gums that bleed after brushing.

COMPLICATIONS

Plaque and tartar can lead to

• Cavities

• Gingivitis and periodontal disease

• Tooth decay and loss

• Tooth infection ( Abcessed tooth)

DIAGNOSIS

Since plaque can cause cavities, dental X rays to check cavities. Dental hygienest uses instruments during regular checkups to find and remove plaque

MANAGEMENT AND TREATMENT

Good oral hygiene includes regular brushing and flossing, removes plaque and prevents tartar buildup.

● Fluoride treatments : to slow the growth of plaque causing bacteria and stop tooth decay

● Chlorhexidine Mouthwash

● Dry mouth medication : to increase saliva production

PREVENTION

Plaque can be prevented by :

● Floss daily: Floss once a day with dental Floss or water flosser to get rid of food and plaque stuck between teeth. Studies shows that flossing before brushing teeth removes more plaque

● Brush twice a day: brush for 2 minutes with soft bristled toothbrush and fluoride toothpaste

● Use mouthwash : rinse with an over the counter or prescription antiseptic mouth wash

● Choose healthy food: Cut down sugary, starchy foods and drinks

Source: healthline.com

Lateral wall of nose

STRUCTURE

Lateral wall of nose has three owing projections called as conchae. These conchae increase the surface area

Lateral wall of the nose is partly made up of bone and partly by cartilage and partly made up of soft tissues

Lateral wall is subdivided into three parts

• Small depressed area in the anterior part is called vestibule which contains short and stiff hair called vibrissae

• Middle part is called as atrium of middle meatus and posterior part contains conchae and space separating conchae are called meatus

Conchae and meatuses

Nasal conchae are curved bony projection which are directed medially and downwards

● Superior concha and middle concha are made up of ethmoid bone and inferior concha is an independent bone

● Meatuses are the passages beneath overhanging conchae. Each meatus will communicate with nasal cavity proper

● Inferior meatus is present underneath the inferior concha and it’s largest of all meatuses. nasolacrimal duct opens into it and it’s opening is guarded by hasner’s valve

● Middle meatus lies underneath the middle concha. Frontal air sinus , anterior ethmoidal air sinus and maxillary sinus opens into it

● Superior meatus lies below the superior concha. It receives openings of Posterior ethmoidal air sinus

● Sphenoethmoidal recess is triangular fossa present just above superior concha it receives opening of sphenoid air sinus

BLOOD SUPPLY

● Anteriosuperior quadrant is supplied by anterior ethmoidal artery and assisted by posterior ethmoidal artery. Anterioinferior quadrant is supplied by branch of facial artery

● Posteriosuperior quadrant supplied by branches of sphenopalatine artery. Posterioinferior quadrant is supplied by greater palatine artery

● Venous drainage : Veins form plexus which anteriorly into facial vein and posteriorly into pharyngeal plexus of veins

● Nerve supply : Anteriosuperior quadrant is supplied by anterior ethmoidal nerve branch of opthalmic nerve. Anterioinferior quadrant is supplied by anterior superior alveolar nerve, branch of infraorbital and continuation of maxillary nerve

● Posteriosuperior quadrant is supplied by lateral posterior superior nasal branches of pterygopalatine ganglion. Posterioinferior quadrant is supplied by anterior palatine branch from pytergopalatine ganglion

Clinical significance

Hypertrophy of mucosa over inferior nasal concha is a common feature of allergic rhinitis which is characterised by sneezing , nasal blockage and excessive nasal discharge from nose. Drugs like Nasal decongestants and antihistamines may be given.

Reference : B.D chaurasia

Tongue (part -2)

Functions of tongue : deglutition, taste sensation, speech, mastication

Blood Supply

●Tongue is mainly supplied by lingual artery branch of external carotid artery, tonsilar branch of facial artery and Ascending pharyngeal artery branch of external carotid artery

● Venous drainage : dorsal lingual veins and deep lingual veins

● Sensory supply: lingual nerve supplies anterior 2/3rd of tongue, glossopharngeal nerve supplies posterior 1/3rd of tongue, Vagus nerve supplies posterior most part of tongue

● Motor supply : All extrinsic and intrinsic muscles of the tongue are supplied by hypoglossal nerve except palatoglossus supplied by vagus nerve

Clinical significance

● Ankyloglossia (tongue tie) : Occurs due to abnormal length of frenulum that extends to the tip of the tongue . Ankyloglossia can be corrected surgically.

● Fissured tongue: Occurs when small furrows present on dorsal surface of the tongue. They are generally painless and benign and often associated with other syndromes

● Geographic tongue: asymptomatic and benign characterized by presence of red patches with greyish white border covering dorsum of tongue

Interesting facts

● An average adult has 2000- 4000 taste buds

● You cannot see your taste buds with naked eye. Those tiny pink and white bumps you see are actually papillae

● Tongue muscles are only muscles in the body working independent of the skeleton

● An oversized tongue is indicative of sleep apnea disorder

● Children sense flavours more intensely compared to adults. Umami is new variant of taste , monosodium glutamate is chemical responsible for this taste

● Women have shorter tongue than men.

● Your tongue is germ free only of its pink. If it is white there is a thin film of bacteria on it

● Blue whale has largest tongue in animal kingdom and weighs 5400lbs

Reference: B.D chaurasia and interesting facts from google

Tongue (part-1)

● Tongue is the muscular organ situated in the floor of the mouth

It has 2 surfaces

• Superior surface

• Inferior surface

● Superior surface is divided into 3 parts Anterior 2/3rd or oral part , posterior 1/3rd or pharyngeal part and base or root of the tongue

● Anterior 2/3rd and posterior 1/3rd are divided by V shaped sulcus terminalis, they are structurally and developmentally distinct.

● Inferior surface is covered by smooth mucous membrane. In midline a mucosal fold called frenulum connects tongue with floor of the mouth

● Lateral to frenulum deep lingual veins can be seen through mucosa lateral to lingual vein , mucosal fold called plica fimbriata is present

PAPILLAE OF TONGUE

Superior surface of tongue contains numerous papillae and have taste buds on their surface

Types of papillae

• Circumvalate papillae : present in front of sulcus terminalis , largest among papillae 8 to 12 in number

• Filliform papillae : Thin, long papillae with pointed ends. No taste buds. Identified by keratinization.

• Fungiform papillae: Slightly mushroom shaped , larger than Filliform papillae and present at apex of tongue and margins

• Foliate papillae : short vertical folds , present lateral to terminal sulcus and at margins

TASTE BUDS

Taste buds are sensory receptors for taste. Sensation of taste is called gustation.  Taste buds are located on surface of all papillae except Filliform papillae

Four taste sensation are sour, sweet, salty,  bitter and recently added is umami

MUSCLES OF TONGUE

● Intrinsic muscles: Main function is to alter the shape of the tongue ,they originate and insert within the tongue and no bony attachments.  ( 4) superior longitudinal,  inferior longitudinal,  vertical and transverse muscles

● Extrinsic muscles :  These muscles take origin from outside of the tongue and alter the shape as well.(4) Genioglossus, hyoglossus, styloglossus and palatoglossus

Superior longitudinal muscle: It lies just beneath dorsum of tongue. Action: It curls the tip upward and roll it posteriorly

Inferior longitudinal muscle : lies on each side lateral to the Genioglossus muscle. Action : To curl the tip of the tongue inferiorly

                                    

Transverse muscle: lies inferior to the superior longitudinal muscle and run from the septum to margins. Action : They narrow the tongue and increase the height

Vertical muscle: It lies inferolaterally to the Dorsum of tongue. Action : flattens the Dorsum

Genioglossus : origin- from superior mental spine and gets inserted into mucous membrane of tongue. It’s action is to protrude tongue, depress central part of tongue and increase the volume of sucking

Hyoglossus : origin- from greater horn and body of hyped bone and gets inserted to side of the tongue. It’s action is to depress side of the tongue assisting Genioglossus to enlarge the oral cavity

Styloglossus : origin- lower part of styloid process and upper part of stylohyoid ligament and inserts on side of the tongue. Action is to elevate and retract the tongue

Palatoglossus : origin- from soft palate and insertion lateral margin of tongue

♢ Styloglossus and palatoglossus attach the tongue Superiorly ,while Genioglossus and hyoglossus attached to the tongue inferiorly

♢ All the extrinsic and intrinsic muscles of tongue are supplied by hypoglossal nerve except palatoglossus supplied by vagus nerve

Reference: B.D chaurasia

Baroodontalgia

• Baroodontalgia refers to baro- pressure odonto – teeth Algia- pain. It’s also called as Aerodontalgia or flyers tooth or tooth squeeze

• It is the pain in the teeth caused due to changes in pressure which may be seen in case of high altitude as seen in pilots and in deep sea divers who also see severe changes in pressure which lead to pain in the tooth.

• Baroodontalgia is usually seen in teeth which have pre existing dental pathology or have improper dental treatments such as chronic pulpitis is the primary culprit; Restored teeth are more likely to be involved ; Maxillary sinusitis; Improper fillings Carious teeth and periapical cysts

• Note that normal teeth without any underlying pathologies are not affected by any change in pressure.

• Baroodontalgia occurs during initial pressure from 14.7psi to 12- 18 psi.

Why there is pain in tooth due to pressure change?

• Due to change in external pressure there will be expansion of gas with compensatory increase in pressure within the pulp chamber and root canal of the tooth which is defective due to any underlying pathology

• Direct pressure in the exposed nerve endings and microleakage of Restorative material from a faulty restoration

• pain is most seen in maxillary posteriors and results from compromised blood supply to the tooth

• In pulpitis – pain on ascent and relief on descent and in Necrosis – pain on decent and relief on ascent

TREATMENT :

– Hyperbaric oxygen therapy is the treatment to avoid baroodontalgia where the person is put in a 100% compressed oxygen chamber which prepares the body for high pressures and compression

– Identification of underlying dental pathology and getting treated properly.

Source:- healthline.com

4th ventricle of brain

• Ventricles are the sites for CSF production.

• lateral Ventricles are the largest and most proximal. Interventricular foramen of Monro connects lateral ventricle and third ventricle

• Third ventricle connects fourth ventricle through aqueduct of sylvius.CSF flows through the entire pathway and exits fourth ventricle into surrounding CNS tissue or through spinal cord.

STRUCTURE AND FUNCTION

• As said earlier , Ventricles are the sites for CSF production. Majority of CSF is produced by choroid plexus. Although lateral Ventricles also produce most of the CSF due to their larger surface area

• CSF gets produced in all Ventricles. CSF provides support to brain, absorbs shock during trauma,keeps neurons in homeostasis, provides nutrition and contain immune cells that fight against infections of nervous system

• fourth ventricle is most inferiorly located directly draining into spinal cord.

• Superiorly it connects third ventricle through cerebral aqueduct of sylvius. Anteriorly it’s surrounding by pons and medulla . Posteriorly by cerebellum and inferiorly by spinal cord.

• lateral apertures or foramen of luschka and median aperture or foramen of magendie. These apertures help the spread of CSF around the spinal cord and surrounding neural structures. All the CSF produced does not drain out of these aperture goes into central canal of spinal cord

EMBRYOLOGY

• Neural tube forms around 4th week of gestation. Three dilation that form neural tube are procencephalon, mesencephalon and rhombencephalon.

• Procencephalon or forebrain develops into telencephalon and diencephalon . Mesencephalon becomes the midbrain while rhombencephalon grows into metencephalon ( pons and cerebellum) and melencephalon (medulla)

• Within each of these dilations that develop from neural tube are cavities that become Ventricles

• The cavity located in rhombencephalon becomes fourth ventricle

BLOOD SUPPLY

posterior inferior cerebellar artery , anterior inferior cerebellar artery and superior cerebellar artery supplies majority of blood flow to fourth ventricle

CLINICAL SIGNIFICANCE

• Ependymomas are the third most common pediatric brain tumour. They are CNS malignancies that originate from the ependymal lining of Ventricles. These tumours are often treatable or require surgery to remove these tumors

• Hydrocephalus is presence of too much of CSF, which often results problem with CSF absorption. A condition called fourth ventricle outlet obstruction is a type of non communicating Hydrocephalus where there is disconnection between subarachnoid space and ventricular system

• Dandy walker malformation (DWM)that demonstrates a cystic enlargement of fourth ventricle and agenesis or hypoplasia of cerebellar vermis . CNS disorders associated with DWM include holoprosencephaly, neural tube defects and dysgenesis of corpus callosum

Reference :- B.D chaurasia

Laser dentistry

• laser dentistry potentially offers a more comfortable treatment option for number of dental procedures

• The term LASER stands for “light amplification by stimulated emission of radiation”. Use of laser proved to be an effective tool to increase efficiency , specificity, ease, cost and comfort of the dental treatment.

• The instrument creates light energy in a very narrow and focused beam. This laser light produces a reaction when it hits tissue allowing it to remove or shape the tissue.

• Types of lasers used in dental practice can be classified by various methods . According to laser medium used gas laser, solid laser ; According to tissue applicability hard and soft tissues ; According to range of Wavelength.

Common hard tissue procedures include :-

-Cavity detection. Lasers can detect cavities early by finding evidence of tooth decay.

-Tooth preparations and dental fillings. Local anesthesia and traditional drills are often not needed with laser treatments. Lasers can kill bacteria in a cavity, which can aid in the long-term health of a tooth.

– Treating tooth sensitivity. Teeth that have sensitivity to hot and cold can be treated with dental lasers that seal tubules on the tooth’s root.

Common soft tissue procedures include :-

-Treating a “gummy smile.” Lasers are used to reshape gum tissue associated with “gummy smile,” in which the gums’ length covers much of the tooth.

-Crown lengthening. This procedure reshapes both gum tissue and bone for healthier tooth structure, which helps with placing restorations on the teeth. Treating tongue frenulum attachment. Those with a thick or tight frenulum (the fold of skin under the front part of tongue that anchors to the mouth floor) may benefit from a laser frenectomy. This treatment helps children whose restricted frenulum causes them to be tongue-tied, have difficulty breastfeeding, or have a speech impediment.

-Removing soft tissue folds. Lasers can remove soft tissue folds from ill-fitting dentures without pain or sutures.

Other laser procedures include:-

-Optical coherence tomography allows a doctor to safely see inside a tooth or gum tissue.

-Removing benign tumors. Lasers can remove tumors from the palate, gums, and sides of the lips and cheeks through a pain- and suture-free method.

-Treating obstructive sleep apnea.  Lasers can reshape the throat and relieve associated breathing problems when sleep apnea is caused by tissue overgrowth in the throat.

-TMJ (temporomandibular joint) treatment. Lasers can help reduce pain and inflammation in the joint.

– Nerve regeneration. Lasers can help regenerate damaged blood vessels, nerves, and scars.

-Treating cold sores. Lasers can minimize healing time and reduce pain from cold sores.

-Teeth whitening. Lasers speed up the bleaching process

Benefits of laser dentistry over other methods :-

– There is potentially a decreased need for sutures with soft tissue lasers.

-Bleeding is minimized in treated soft tissues, as the laser promotes blood clotting.

-With some procedures, anesthesia is unnecessary.

– The chance for bacterial infections is lower because the laser sterilizes the area.

-Wounds can heal faster, and it’s possible for tissue to regenerate. The procedures may involve less damage to the surrounding tissues.

Disadvantages of laser :-

– Lasers can’t be used on teeth that already have certain types of filling, such as metal amalgam.

-Hard lasers can sometimes injure tooth pulp.

-Some laser procedures still require anesthesia.

– Drills are still sometimes needed to complete fillings, including shaping, adjusting the bite, and polishing the filling.

Source:- http://www.healthline.com

Biomechanics of edentulous state

What is biomechanics?

It’s the interaction between the biological environment and the mechanical device that is fixed or removable prosthesis is called as biomechanics.

• They are 2 types of forces that is horizontal and vertical.

• The forces are directed in the vertical direction to the long axis of the tooth. Forces transferred by vertical direction are during mastication, clenching and swallowing.

• The forces transferred by the vertical direction is much more than the horizontal direction.

• The forces transferred by horizontal direction are mainly by the tongue and by perioral musculature.

• The factors for edentulism are trauma, patient’s oral hygiene, ageing , attitude of the patient , diet and financial status.

• If the forces are directed obliquely then the bone remodelling takes place and bone deposition will occur.

• In natural dentition , masticatory forces will be transferred through the periodontal ligament to the bone. The arrangement fibres in periodontal ligament also plays a major role.

• The periodontal ligament acts like a cushion and distributes the masticatory forces.

• The tooth is supported by the periodonium. Hard tissues supporting are cementum and bone and soft tissues are PDL and lamina propria of gingiva covered by the epithelium.

• The load taken up by the natural dentition is 20 kg and that in complete denture wearers is 8 kg.

• The major difference between the natural dentition is the compressibility of PDL and in the complete denture patient the oral mucous membrane has less compressibility to deliver forces.

• Normal mastication – 30 sec. Act of deglutution – 18 sec.

• We swallow about 500 times in a day and masticate about 17 minutes approximately in a day.

Reference :- deepak nallaswamy