PIA answer in text Flashcards
What are the symptoms and what is the physiological mechanisms of Vasovagal syncope?
Sympyoms: Light-headedness, narrowed vision, nausea.
Physiological mechanisms:
1. Sudden decrease in blood pressure due to stress
2. Decreased blood perfusion to the brain
3. Results in brain shut down due to low levels of oxyegn in the brain
What are the symptoms and what is the physiological mechanisms of Postural hypotension?
Symptoms: Light-headedness/dizziness, blured vision, weakness, nausea
Physiological mechanisms:
1. Prolonged periods of being in supine position
2. Blood pools in veins of legs
3. There is a decrease in venous return
4. Decreases venous return reduces the cardiac output
5. Decrease in cardiac output results in decrease blood pressure, because blood pressure equals to the product of cardiac output and systemic vascular resistance
6. When patient rises to a sitting position and standing position, the reduced blood pressure causes a deficit of oxygen travelling to the brain
7. Brain has an absolute need for oxygen, thus when there is a deficit, it shuts down
What are the symptoms and what is the physiological mechanisms of Changes in BGL?
Symptoms: Constant hunger, nausea, blurred vision, confusion
Physiological mechanisms (possible mechanism):
1. High blood glucose levels
2. Polyuria
3. Dehydration
4. Impared cognitive functions
5. Decrease in blood volume, decrease in systemic peripheral resistance, resulting in decreased blood pressure because blood pressure equals to the product of cardiac output and total peripheral resistance
6. Syncope due to brain shutting down due to low oxygen perfusion
What are the symptoms and what is the physiological mechanisms of hyperventilation syncope?
Symptoms: Weakness, confusion, dizziness, shortness of breath
Physiological mechanisms:
1. Ventilation exceeds body’s metabolic needs for CO2 removal
2. Partial pressure of CO2 in blood decreases
3. Blood pH increases due to respiratory alkalosis
4. Hypocapnia
5. Cerebral vasoconstriction
6. Lowered cerebral perfusion
7. Syncope due to reduced cerebral perfusion
What are the procedures in SADS to deal with a syncope?
- Stop dental treatment
- Implements DRSABCD:
Danger
Response
Send for help
Airway
Normal Breathing
CPR
Defibrilaetor - Call your tutor
- After incident, require dental record documentation including completing SLS incident report & debriefing with tutor
What to do in SADS if a patient shows symptoms of syncope?
- Stop dental treatment
- Elevate patient’s legs to achieve a position where their head is lower than the heart. If patient is in dental chair, tilt the chair back to a horizontal angulation
- Allow patient to recover slowly
- Measure patient’s blood pressure & heart rate
What are systemic manifestations of diabetes?
- Micro & Macro vascular damage
- Retinopathy
- pEripheral Vascular Disease
- Cardiac Disorders
- Kidney Problems
- Nerve Damage
What are oral manifestation of diabetes?
- Caries risk & Periodontal disease
- Xerostomia
- Slow healing ability
- Susceptibility to developing oral mucosal disease
- Taste disturbance
- 2-way interaction of oral infections & increased BGL
What are the steps to radio-graph assessment?
- Exposure
- Detector orientation
- Horizontal detector positioning
- Vertical detector positioning
- Horizontal beam angulation
- Vertical beam angulation
- Central beam position
- Colimator rotation
- Sharpness
- Overall diagnostic value
What are the steps to gingival assessment?
C - colour
C - contour
C - consistency
T - texture
E - exudate
What are the steps to ILA?
- Patient
- CC
- MHx
- SHx
- DHx
- Exam
What is TRIM?
TRIM is an acronomy for:
Timing
Relevance
Involvment
Method
What is differential diagnosis?
It is a process where a physician is able to assign probability of one illness in comparison to others accounting for patients sympotms.
What is a white spot lesion?
A white spot lesion is an incipient caries lesion, it has a dull opaque chalky appearance and occurs due to demineralisation of enamel caused by cariogenic bacteria
What is the pathogenesis of caries?
- Cariogenic bacteria requires simple sugars for anaerobic respiration
- Glucose is processed through glycolysis in the cariogenic bacteria
- Glucose is converted into 2 pyruvate
- In order to than convert NADH electron carrier into NAD+, pyruvate is converted into lactic acid
- Lactic acid accumulates in the cariogenic bacteria and is released into the oral environemnt
- Lactic acid has pH of about 2.35 which is slower than the critical pH of hydroxyapatite which means Lactic acids is able to cause dissociation of hydroxyal groups in hydroxyapatite which leads to demineralisation of the enamel
How can we remineralise a tooth?
In presence of Calcium, Phopshate and/or Fluoride in the biofilm or in salivary pool, if pH of above 4.5 is restored the tooth would be immediatley remineralised
Why is fluoride so effective?
- It is able to stop cariogenic bacteria metabolism
- Drive remin
- Create fluoride salivary pool
Why is calcium still needed for fluoride incorpiration?
Fluoroapatite still needs calcium and phosphate
How would you describe WSL
L - location
C - colour
T - texture
C - contour
What are the functions of the salivary proteins and dissolved materials?
1.Acid neutralisation
2.Promotion of remineralisation
3.Creation of pellicle
4.Antibacterial properties
What type of buffer does stimulated saliva?
Bicarbonate
What type of buffer is in unstimulated saliva?
Phosphate
What can change the balance of the oral environment?
1.More refined, softer foods
2.Refined CHO
3.Increase in fermentation
What are the steps to bonding resin to enamel?
1.Prophylaxis
2.Acid treatment – for microporosities – increase of surface area for interlocking in the area and create a macromechenical bond – increase of surface area by 2000 times
3.Wash and dry – stop the demin process and remove moisture
4.Fluid (unfiled) resin – flow into microporosities to create resin tags – chemical bonding
5.Unfilled resin polymerised
6.Composite resin placed
7.Polymerised
What are the steps to bonding to dentine?
Etching – this will expose collagen – may cause pulpal fluid to flow up which can compromise the bond – etch for a little less
Use a primer – wet or dry – dry: collagen is collapsed which rehydrated – wet: small amount of water remains – creation of hybrid zone
Unfilled resin
Polymerise
Filled resin
Polymerise
How do GIC bond?
They bond chemically throguh ion exchange and can exchange ions with tooth and oral environment.
Why do we need to protect the GIC during the maturation phase?
GIC are vulnerable to take-up of extra water or water loss. This may create a loss in physical properties. This can be avoided by layering of unfilled resin of G-coat over the top.
What are the steps in applying GIC?
1.Clean the surfaces with pumice and water – for better ion exchange
2.Use Polyacrylic acid – depending on % - to remove the smear layer and exposure the clean tooth surface for ionic exchange
3.Wash it off – stop the reaction
4.Dry but do not desiccate – stop flow of dentinal fluid
5.Place GIC
6.Protect in the moisture sensitive phase
What are the steps of amalgam placing?
1.Remove caries or remove failed amalgam
2.Consider depth of cavity – at least 2 mm into dentine
3.Remove unsupported enamel
4.Retention - macromechanical retention
5.Liner/base
6.Pack amalgam using a plugger – permite ect amalgam used in sim
7.Burnish
8.Carve using cuspal inclines
9.Articulating paper and adjustment
10.Polish 24 hours later
What are some of the techniques for caries diagnosis?
1.Visual Examination – clean, dry, illuminate well and use the tip of the explorer
2.Radiographs - just remember of superimposition, it is probably bigger than it is on radiographs
3.DIAGNOdent - measuring reflected light – little to no florescence in clean, healthy teeth
What are some of causes of damage to the dentine and pulp?
1.Caries - through bacterial acids, toxins and enzymes
2.Micro-leakage – due to unsealed margins – could cause sensitivity and recurrent caries – seal so bacteria can go into a dormant state
3.Mechanical damage – fracture, cavity preparation, cracked cusps, dehydration
4.Thermal damage – during cavity preparation friction, polishing, absence of insulation (base & liner)
5.Chemical damage – Hema & Tegma & other acids
What type of questions can we ask the patient about their pain?
1.Location
2.Commencement of pain
3.Character of pain
4.Frequency
5.Duration
6.Time
7.Precipitation factors
8.Other complains
Explain hydrodynamic theory.
Dentinal tubules contain an extension of the odontoblasts (odontoblastic process) in the part of the tubule that is proximal to the pulp. Around the odontoblastic process, coiled are small nerve extensions. The rest of the space inside a dentinal tubule is filled by dentinal fluid.
If the fluid is disturbed through heat, cold, dehydration and even touch and pressure, it causes the fluid to move which activates the pulpal nociceptros around the odontoblastic processes this cause an action potential and signals for pain.
How do we assess the fractures?
1.Tissue exposed – enamel only, enamel and dentine or exposed pulp
2.Surfaces involved
3.Check occlusion
What is the pattern of erosion relating to intrinsic sources?
1.Upper posteriors are affected first
2.Diffuses and affects the upper anterior next
What is the pattern of erosion relating to extrinsic sources?
1.Occlusal of lower affected first
2.Palatal of upper anterior
How would you assess the teeth on the radiograph?
- State what radigraph and side you are looking at
- FDI: notatation with restorations and radioopacities
- Pathology: radiolucencies, extent and causes
How would you identify gingivitis?
1.Localised - 10% - 30% BOP
2.Generalised - >30% BOP
No pain or no clinical attachment loss
How would you identify periodontitis?
Proximal clinical attachment loss of equal or above 2 teeth, non-adjacent
OR
Buccal/oral clinical attachment loss of 3mm with 3mm pocketing at 2 teeth or more
What are the steps to occlusal analysis?
1.Teeth present/missing
2.Morphology of teeth
3.Wear - mild, moderate, sever
4.Crowding,spacingrotations
5.Axail inclanations
6.Shape of dental arch
7.Cruve of spee and wilsons curve
8.Angle molar classification/canine classification
9.Overbite (%) / overjet (mm)
10.Mediolateral
What is the 4A’s framework?
Ask, assess, acknowledge and address that can be used to adress a patient with dental anxiety
What is ALARA?
It stand for as low as reasonably possible - which is a concept used in radiography in order to reduce radiation exposure for both the operator and patient.
1.Keep your distance
2.Shield
3.Do not take unnecessary radiographs
What is the needle stick inury protocol in dental emergencies?
- Stop
- Place needle/sharp aside
- Take off gloves
- Wash hands with soap and water
- Dry and cover with non-stick dressing
- Apply pressure if bleeding
- Let tutor know
- Contact SADS registered nurse for risk assessment
- Write up incident report - SLS
What is stage 1 periodontitis?
1.1-2mm attachment loss
2.Coronal third bone loss
3.No tooth loss
4.Maximum probing depth of below 4mm
5.Mostly horizontal bone loss
6.Extent variable
What is stage 2 periodontitis?
1.3-4mm attachment loss
2.Coronal third bone loss
3.No tooth loss
4.Maximum probing depth of below 5mm
5.Mostly horizontal bone loss
6.Extent variable
What is stage 3 periodontitis?
1.5mm or more attachment loss
2.Bone loss extending to middle or apical third of the root
3.Tooth loss due to periodontitis of 4 or less teeth
4.Probing depth of 6 mm or more
5.Vertical bone loss of 3 mm or more
6.Class II or III furcation
7.Moderate ridge defect
What is stage 4 periodontitis?
1.5mm or more attachment loss
2.Bone loss extending to middle or apical third of the root
3.Tooth loss due to periodontitis of 5 or more
4.Probing depth of 6 mm or more
5.Vertical bone loss of 3 mm or more
6.Class II or III furcation
7.Moderate ridge defect
8.Mastication disfunction
What is Grade A periodontitis?
When there are no evidence of loss over 5 years
What is Grade B periodontitis?
When there is a below 2 mm loss over 5 years.
What is Grade C periodontitis?
When there is an above 2mm loss over 5 years
What are two types of local anaesthetic?
- Amino esther - broken down by enzymes
- Amide type - metabolised in the liver
What is the mechanism of action of anaesthetics?
The molecules bind to amino acids on amino acids, and simply blocking the channel. This does not allow for depolarisation thus stop the propagation of action potential.
What is the main problem that LA needs to overcome prior to blocking the sodium ion channel?
To get through the phospho-lipid bi-layer of the cell membrane
How do we modify local anathetic to overcome the phospho-lipid bilayer?
We design it to be amphiphatic
What does the pKa in local anaesthetic represent?
It represent the balance between charged and uncharged molecles of the solution. I.E. at pKa 7.6 there is equal number of molecules, thus at pH 7.6 there will be am equal number of molecules
What is the importance of RN in local anaesthetic?
The uncharged RN molecules, represent the number of molecules that can pass through the phospho-lipid bi-layer as they are water soluble. Turns to RNH+ which actually bind to sodium channel.
Why is the pH of injecting site important?
The pH at the injecting site may alter the numbers of RN making it unable to diffuse into the cells.
What happens when the pKa of LA is high?
This can decrease the number of RNs at the injection site thus will prolong the onset of the anaesthetic.
What is the objective of vasoconstrictors in LA?
1.Decrease blood flow
2.Slow absorption of LA into blood stream
3.Maintain higher local concentrations of LA
4.Longer duration of LA action
5.Reduced bleeding
What are the most common local anaesthetics and their vasoconstrictors?
- 2% Lignocaine (Xylocaine) with 1:80000 adrenaline
- 3% Prilocaine (Citanest) with 0.03 iu/ml octapressin
- 3% Mepivacaine (Scandonest Plain) - no vasocontrictor
- 4% Articaine (Articadent) with 1:100000 adrenaline
What is the standard local anaesthetic equipment?
- Aspirating and non-aspirating syringes
- Short (25mm) and long (40mm) needles
- 25, 27 (the usual size, and 30 gauge needles
- Glass cartridges
What are 3 commonly used LA techniques?
- Topical
2.Block
3.Infiltration
What are the landmarks that help to locate teh site of IAN?
1.Level - coronoid notch, 1cm above lower occlusal plane, midway between arches with mouth wide open, buccal pad
2.Angle - opposite premolars
3.Entry point - pterygotemporal depression
What are the 4 main abilities of pathogenesis?
1.Attache to host
2.Entry into host
3.Colonisation and growth within the host
4.Ability to avoid host defenses
What are the 5 Pathogenic Determinants pf Cariogenic Bacteria?
- Sugar transport - high and low affinity transport systems
- Acid production for proliferation
3.Aciduricity - ability to survive in acidic environments
4.EPS production - contributions to plaque matrix
5.IPS production - allows for production of acit when sugar is not available
What is hypoplasia?
It is the reduction in the amount of enamel matrix produced - presents as pitting, may caause sensitivity
What is hypomineralisation?
It is the inability for sufficient organic material to be removed during maturation stage of amelogenesis - presents as variation in colour from white-yellow-brown, teeth are highly vulnerable to staining and tooth wear
What is hypocalcification?
It is insufficient inorganic material deposition during maturative stage - teeth adopt chalky, yellow appearance, highly vulnerable to staining and tooth wear
What are 3 types of enamel defects?
- Hypoplasia
- Hypomineralisation
- Hypocalcification
What is the aetiology of periodontitis
- Bacterial build in biofilm - dominance of gram negative and opportunistic bacteria
- Gram negative bacteria release LPS
- This triggers an inflammatory response
- Influx of neutrophils (due to release of IL-8 by epithelial tissue) to form palisade
- Release of pro-inflamatory cytokines and enzyme - chemotaxic agents for leukocytes & marcophages
- Need for creation of space for cells - break down of collagen fibres and lateral prolifiration + apical migration of the junction epithelium - creation of the pseudo pocket due to oedema
- End result - damage to collagen but no damage to periodontal attachmnet
Give example of two local and two systemic factor for gingivitis and periodontitis.
Local: calculus and over hangs - more sites for harbouring of bacteria, xerostomia - reduciton in anti-microbial effect of saliva
Systemic: Smoking - reduction in blood flow and immune function - more periodontopathogens arise,; Diabetes - increased formation of Advanced Glyation End Products - increased osteo clast function and oxidative stress - increased tissue destruction
What are some of the treatment for perio?
Debridment.
Remember that long axis to the tooth should be parallel to the terminal shank
What happens to unpolarised resin?
It may damage the pulp because it is toxic thus it needs to be polymerised. Becomes a problem in wet environment or when placed in large increment.
What are the steps to bonding resin to enamel?
- Prophylaxis
- Acid treatment – for microporosities – increase of surface area for interlocking in the area and create a macromechenical bond – increase of surface area by 2000 times
- Wash and dry – stop the demin process and remove moisture
- Fluid (unfiled) resin – flow into microporosities to create resin tags – chemical bonding
- Unfilled resin polymerised
- Composite resin placed
- Polymerised
What is a closed sandwich technique?
When GIC if covered around with another material
What is an open sandwich technique?
When GIC is exposed outside the tooth – to the oral environment
Why do amalgam may need liners & base?
Due to their thermal properties
What are some of the materials are used in pulp protection?
- Varnishes - copalite – used to block dentine tubules – bad longevity
- Liners - cover the dentine – placed under restorations – used for shallow cavity – CaOH cement (Life) - very alkaline - GIC line bond LC
- Bases - similar to liners but are thicker – use as dentine replacement – ZnPO4 cement is an example – Zinc Oxide-Eugenol is another example – GIC like the Fuji series
Name 3 components of saliva that have anti-bacterial properties.
- Non-immunological defences
- Physico-chemical barriers
- Immunological barriers
How does the flow rate of saliva vary during 24hr cycle?
The rate of saliva production is relatively high during the day and decreases significantly during the night time
Is there an identified pathogen that causes gingivitis?
No. Gingivitis is a result of bacterial accumulation which could be the same type of bacteria or transition of bacteria from gram positive to gram negative.
What are the main features of randomised control trials?
- High level of evidence
- Eandom assignment
- Groups are exchangeable
What are the different types of RCTs?
- Parallel-arm RCTs
- Cross-over RCTs
- N-of-1 ‘single patient’ RCT
What is the structure of the parallel-arm RCTs?
- Selection
- Randomisation
- Treatment and control group establishment and intervention
- Follow up measures
- Analysis
What is the structure of the Cross-over RCTs?
- Selection
- Randomisation
- Treatment and control group and intervention
- Washout period
- Swap of control and treatment groups for second intervention
- Outcomes of interventions
- Analysis
What is the structure of the N-of-1 ‘single patients RCTs?
- One patient is selected
- They go through periods of treatment and non-treatments – the pattern is also random
- Outcomes of interventions are recorded
- Data is analysed
What is the design of a cohort study?
- Time baseline
- Time goes on
- We observe
- Analysis
- Outcome
How does a cross sectional study work?
- Select a group
- See if they were exposed or not
- Analyse
- Outcomes
Why do we do a cross-sectional study?
Have a snapshot and see the prevalence of health problems in a population
What is a perspective study?
The study is conducted before data is gathered.
What is a retrospective study?
The study is conducted after the data is made available.
Why do we sample?
Reduce costs and it is more efficient
What are some of the sampling methods?
- Simple random sample – equal chance being selected
- Stratified random sample – equal participation of sexes, races and other parameters
- Systematic - non-random – a set process e.g. every tenth person
- Clustered - geographic areas are selected, after the clusters of multiple people are selected
- Convenience sampling – just recruit people where we actively recruit people with needed traits
What is the main objective of case control study?
It is causal interference. What can we do to reduce the problem.
What is the main objective of ecological study?
It is casual interference. What can we do to reduce the problem.
What is the design of a case control study?
It starts with a known outcome that is classified as a “case”. Non-cases are treated as a control group.
What is the design of a case control study?
- A group of people with a known disease are classified as cases
- A group of people who are known not to have a disease are used as controls
- Both groups are sampled and separated into exposed and none exposed
- We get 4 groups thus 4 data steams
- Odds are calculated
What are ecological studies?
Ecological studies are epidemiological evaluations in which the unit of analysis is populations, or groups of people, rather than individuals. Example: Is the prevalence of dental caries lower in fluoridated areas?
What is a systematic error?
It relates to the way we conduct studies. It cannot be reduced by increasing sample size.
What is a systematic review?
They are a way of reviewing all the data and results from studies about a specific question in a standardized systematic way
What is empathy?
It is the ability to understand and share other people’s emotions.
In what form does LA exist in the solution?
- Unchanged lipid soluble molecules that are referred to as the base - more of it exist the better LA works - it can defuse through the cell membrane
- Positively charged molecules RNH+ - this is the molecules that is able to inhibit the work of the Sodium channels in neurons which disables the propagation of action potential - it can not defuse through the cell membrane
What is the relationship between pH and Rn and RNH+?
1.When pH is low, there is a large number of RNH+ as RN is converted into RNH+
2. IF pH is high, there is a large number of RN
How much of myelinated fibre needs to be covered by anaesthesia in order to anaesthetised the nerve?
8-10 mm
What are two main objective of LA?
- The LA must diffuse through the nerve sheath
- The LA must bind at receptor sites in the nerve membrane
What determines the number of basic and cationic forms of LA?
- The pKa of the solution
- The pH of the LA solution
- The pH of the site of injection
What does methylparaben do in LA solution?
Acts as an anti-bacterial preservative but has the
potential to cause allergy
What does bisulphite do in LA solution?
Acts as an anti-oxidant for the vasoconstrictor and
also tends to lower the pH of the LA solution. May
cause allergy problems
What does sodium chloride do in LA solution?
Makes the solution isotonic
What does sodium hydroxide do in LA solution?
Added to some LAs to adjust the pH
What does distilled water do in LA solution?
Used to dilute the solution and increase its volume
What does vasoconstriction do for LA solution?
- Decreased rate of absorption into the blood stream
- Increased duration of action and effectiveness
- Decrease bleeding at the site of injection, and
What are the 3 essential components of local anaesthetic equipment?
- Syringe
- Needles
- Cartridge
What are two common needles in SA dental clinics
1.Short, 25 mm length, 27 gauge
2.Long, 40 mm length, 27 gauge
What are 5 common anaesthetics in SA dental?
- Lidocaine hydrochloride - Lignospan
- Prilocaine hydrochloride - Citanest
- Mepivacaine hydrchloride - Scandanest
- Articane hydrochloride - Septanest
- Bupivacaine hydrochloride - Marcaine
What type of topical anaesthetic is used in SA dental?
Benzocaine, 15-30 seconds applied to the area of anaesthetic
What are two main technique in LA?
- Supraperiosteal infiltration - diffusion through cortical bone
- Nerve block - depositing solution to a nerve trunk
What are types of infiltration can be administered?
Labial, buccal or palatal
What types blocks are available for the maxilla?
- Maxillary - blockes whole of maxillary nerve
- Tuberosity - blocks posterior superior alveolar nerves
- Infraorbital - blocks anterior superior alveolar nerves
- Nasopalatine - anaesthetises palate back to canines
- Greter palatine - anaesthetises palate as far forward as canines
What are the steps of labial or buccal infiltrations?
- Position the patient
- Pull lip or cheek firmly out
- Define the fornix
- Wipe if necessary, then apply small amount of typical
- Insert needle, bevel towards bone, in the fornix
- Keep close to bone without touching, insert 2-3 mm, parallel to long axis of tooth
- Inject slowly (1-2ml depending on the procedure)
What are the steps to a palatal infiltration?
- Define point of entry
- Apply topical
- Insert needle, approximately at right angles to the palate, at junction of alveolar process and horizontal plate
- Advance needle gently 2-3 mm
- Inject slowly approx. 0.5 ml
Where is the location of injection for the maxillary block?
- Buccally beyond third molar
- Through greater palatine foramen
What are the advantages of palatal block?
Wide area of LA, including maxillary sinus
What some of the technique for anaesthesia of the mandible?
- Infiltration that is only possible in incisor region
2.Inferior alveolar nerve block
How to locate the place for IANB?
- Level - palpate the coronoid notch, find the deepest point
- Entry point - locate pterygotemporal depression. It is between the pterygomandibular fold medially and the ramus of the mandible laterally
- Angle - the angle of insertion is along a line drawn from the opposite lower second premolar to the pterygotemporal depression
What is the location of the inferior alveolar nerves?
It is close to the ramus between the ramus and sphenomandibular ligament that runs from the spine of the spenoid to the lingula
What is the location of lingual nerve?
It is medial and anteriorly to the inferior alveolar nerve and in close proximity to the lateral surface of medial pterygoid muscle.
What are steps to IANB?
- Position patient in chair
- Palpate the right ramus with the left index finger and define the coronoid notch
- Slide finger medially so that the ball of the finger lies in the retromolar area between the external and internal oblique ridges
- Hold syringe in right hand, with the barrel parallel to the occlusal plane. Insert the needle halfway between the fingertip and PMF, with the barrel over premolars on the left hand side
- Advance the needle with minimum force until it touches bone
- Withdraw slightly, aspirate, inject 1-2 ml
- Move barrel towrds midline, withdraw half the amount of insertion, inject for lingual nerve about 0.5 ml
- Complete withdrawal
How to perform anaesthesia of buccal nerve?
- Inject just medial to anterior border of mandible, distal buccal to the last molar tooth around the level of the lower occlusal plane
- Hold the syringe parallel with the occlusal plane on the same side
- Advance the neddle until the needles gently touches the mucp[eriosteum/bone, then slightly withdraw and then inject
What are the steps for a mental block?
- Hold lip between finger and thumb and pull anteriorly and downwards
- Insert needle just lateral to the fornix, distal to second premolar
- Direct the needle medially, anteriorly and inward into the canal. Inject slowly
What nerve innovate the upper molars?
The posterior superior alveolar nerve
What nerve innovates the upper premolars?
The middle superior alveolar nerve
What nerve innovates the anterior upper teeth?
The anterior superior alveolar nerve
During odontogenic infection, what is the path of least resistance in the mandible?
- If above the mylohyoid line, the infection would progress lingually, eroding the lingual cortical plate and entering the sublingual space. This will elevate the tongue and create diffuculties with breathing
- If below the mylohyoid line, the infection would progress down into the submandibular space. This may causes swelling near the angle of the ,and able to potentially causing trismus and therefore diffuculties chewing..
How does an odotontic infection spread if it is not treated?
- Caries reach the root
- Pulpal progression
- Root progression
- Progression to the apex
- Progression into other tissues and cavities
What is the usual cause of infection in the sub mandibular region?
Usually the source is second and third molar because their roots are entirely below the attachment of mylohyoid muscle.
The infection starts in the periodontal pocket and spreads to the musculature of the floor of the mouth. Infection pierces through the lingual cortical plate of the mandible.
The infection moves lingually rather than buccally, as the lingual aspect of the tooth socket is thinner and provides the path of least resistance.
The infection than moves into sublingual space.
What are common routes of pulpal entry for bacteria?
- Exposed dentinal tubules
- Cavitated carious lesions
- Micro leakage of restoration
- Injury
What is the function of odontoblasts during the defence of pulp against bacterial infections?
1.Express Pattern Recognising receptos
2.Secrete antibacterial products
3.Release cytokines for chemo attraction of defence molecules
What is the process of tertiarry dentine formation?
When odontoblasts receive signal about presence of bacteria near the pulp they are able to react by up regulating the production of reactive dentine (tertiary dentine) which creates a barrier between the pulp and the bacteria.
If odontoblasts die, pulp is able to create reperative dentine. The main cells in deploying reparative dentine are the pulp fibroblasts or stem cells.
What is the function of neurovascular network in protection of pulp during bacterial infection?
Secretion of neuropeptides causing vasodilation, vascular permeability increased, and promotion of immune cells. This also promotes tertiary dentine formation
What type of tissue is labial mucosa?
Non-keratinised stratified squamous epithelium. Labial mucosa has many elastic finred for flexibility and blood supply.
What is the main arterial supply to the lips?
It is predominantly supplied by external carotid artery, specifically via the facial artery.
What is the main venous drainage from the lips?
Through superior and inferior labial veins into the facial vein into external jugular and into subclavian vein
What is the main nerve supply to the lips?
The supply to the muscles is via the facial nerve and sensory via trigeminal nerve
What mechanism does the cell regulate for prior to S phase?
1.Cell size
2. DNA damage
What mechanism does the cell regulate for prior to M phase?
- DNA damage
- DNA replication completeness