Primary Care Flashcards
What is the palmar system?
Primary teeth= a-e
Permenant teeth= 1-8
How many teeth are in the primary dentition?
- 2 incisors, one canine and 2 molars
What is the FDI system?
Permanent teeth= 1-8
Primary teeth=1-5
Quadrants numbered 1-8
First 4 are permanent quadrants
What are primary eruption dates?
6-9 months= lower then upper As 7-10 months= lower then upper bs 12-16 months= all ds 16-20 months= lower then upper cs 23-30 months= lower the. Upper es
What is the occlusion at birth?
Gum pads occlude distally
Anterior oval opening to allow suckling
Fleshy labial frenum
What is the 6-10 month occlusion?
Maxillary incisors erupt labially to the mandibular incisors
What is the 36 months/3 year occlusion?
Primary dentition is complete Incisors vertical and spaced Deep over bite Anthropoid spaces mesial to maxillary canine and distal to mandibular canine Flush terminal plane
What is the occlusion at 6 years?
Overbite decreases
Spaces of anteriors
Attrition of incisors
What are the eruption dates of the permanent dentition
6-7 years= lower 6s and 1s, then upper 6s, the upper 1s 7-8= lower 2s 8-9= upper 2s 9-11= lower 3s 10-12=all 4s then all 5s 11-12= upper 3s 11-13= all 7s
What is the mixed dentition occlusion of a 6 year old?
Eruption of first permanent molars
Mesial migration of primary molars
Anthropoid spaces close
Permanent molars in class 1 or half class 2 relationship
Occlusion of 7-8 year old?
Maxillary incisors erupt spaced and more proclaimed the there primary predecessors
Maxillary lateral incisors are often distally inclined
Maxillary incisors labial to mandibular
What is leeway space?
The difference between the combined mesiodistal width of the primary canines and molars, and the permanent canines and premolars
How big is the maxillary arch?
1.5mm
How big is the mandibular arch?
2.5mm due to larger 2nd molars
Describe the 9-12 year occlusion
Primary canines and molars are exfoliated Permanent molars drift into leeway space and form class 1 occlusion
When can we palpate the upper canines?
At 10 years old
Describe the 11-12 year occlusion
The Incisal spacing reduces as the maxillary canines erupt
Describe the 11-13 permanent occlusion
All primary teeth have exfoliated
First permanent molars I class 1
Second permanent molars erupting
What are the potential consequences of loosing primary teeth early?
Delayed or accelerated eruption of the successor
Space loss and crowding in the permanent arch
Should teeth erupt out of sequence?
Eruption dates may vary, but sequence should not
A tooth may not erupt at the same time as it’s contralateral counterpart, but you should not be suspicious until a tooth has still not erupted 6 months after it’s counter part
What were the conclusions of the child dental health survey?
Overall improvements in decay seen in permanent teeth
No significant reduction in decay experienced in primary teeth
Clear regional differences with no change
What are the high risk categories?
Medical history Dietary habits Clinical evidence Social history Use of fluoride Plaque control
What are the medical factors of caries risk?
Medically compromised
Physical disability
Xeristomia
Long term cariogenic medicine
What are dietary factors of caries risk?
Frequent sugar intake
Intake between meals
What clinical signs help determine caries risk?
New various lesions Premature extractions Anterior caries/restorations Multiple restorations No fissure sealants Fixed orth
What social signs help determine caries risk?
Social deprivation High caries in family Low knowledge of dental disease Irregular attendance Readily available snacks Low dental aspirations
What fluoride factors help determine caries risk?
Fluoridated water
No toothpaste/un fluoridated
No fluoride supplements
What plaque control factors which help determine caries risk?
Infrequent or ineffective cleaning
Poor manual control
Prevention strategies of caries
Diet Fluoride Fissure sealants Ohi Prevention of maternal transmission of s.mutans Cpp-acp
What is ecc?
Early childhood caries
dmft in primary dentition before 71 months
Commonly seen due to bottle feeding. Lower anterior teeth spared
What are the causes of ecc?
Frequent consumption of sugary drinks in a bottle
Longer period of exposure to cariogenic substance
Low salivary flow at night
Parental history of untreated caries
What are the characteristics of ecc?
Rampant caries effecting the maxillary anteriors
Lesions appear later on posterior teeth
Canine usually less affected due to later eruption
What are the consequences of ecc?
Higher risk of new carious lesions
Increased treatment cost and time
Risk for delayed physical growth and development
Loss of school days and increased days with restricted activity
Diminished oral health related to quality of life
Hospitalisation and a and e appointment risks
How do we try to prevent ecc?
Reduce parent and siblings strep mutants levels to decrease over all transmission
Minimise saliva sharing activities
Implement oral hygiene measures
Avoid high frequency consumption of foods contains sugar
Encourage infants to drink a cup by 1 year
How do we manage ecc?
Cessation of habit Dietary advise Fluoride application Build up of restorable teeth Extractions if required Appropriate advise, no blame Possible treatment under GA
How do we know if we have successfully managed ecc?
Has the bottle stopped Have oh practises changed No progression of the disease No new lesions Caries shows signs of arresting
What is the purpose of a caries risk assessment?
Helps us treat the risk not the outcome of the disease
Individual selects frequency of protective and restorative treatment
Anticipates progression and stabilisation
Why do we do prevention based on risk?
Because decay is unevenly distributed within a population
What are the none fluoride prevention methods?
Diet modification Oho and dental earth education Fissure sealants Sugar free medicine Chewing gum Chlorhexadine
What did the coma report 1989 say?
Caries is positively related to frequency and amount of non milk extrinsic sugar consumption
Recommended:
Consumption of nmes should be reduced and replaced by fruit, vegetables and starchy food
What is the daily recommended sugar intake according to delivering better oral health?
10% of daily energy intake
Less than 60g per day for adults
Less than 33g per day for young children
What did the vipeholm study show?
Positive correlation between caries and sugar intake
More frequent sugar intake not at meal times leads to increased caries
What was the message of the hope wood house study?
Children ha massively reduced levels of decay compared to the rest of the population due to strict sugar controlled diet
When they left the house and no longer eat the provided diet, levels of decay massively increases
Will toothbrushing help prevent dental decay?
Little evidence to support that tooth brushing alone will prevent caries
However, use of fluoride toothpaste is of benefit
What do the cochranne collaboration say about fissure sealants in children and adolescents?
Recommended in the occlusal surface of permanent molars
Effectiveness is evident at high caries risk
78% less caries in permanent molar teeth with resin based sealer after 2 years and 60% less after 4 years
Some evidence that sealing is better than fluoride varnishes
Who do we fissure seal?
Children and young people with:
Impairments
Caries in primary teeth
Where can we fissure seal?
First permanent molars
Palatal pits of permanent lateral incisors
Second permanent molars and premolars
Primary posterior teeth in children at high risk of caries
Teeth must be erupted enough for good moisture control
How do we etch for fissure sealants?
With 30-40% phosphoric acid for 20-40 seconds
What materials can we use to fissure seal?
Resin
GIC
Compomer
Fluoride contains sealants
Can chewing gum prevent caries?
Xylitol and sorbitol have anti caries properties through saliva stimulation.
Xylitol is more effective than sorbitol
Should encourage patient use
According to sign 47
What does sign 47 say about chlorhexidine?
Can be used prophylactic in the form of rinse, gel or pasteand can achieve a substantial reduction in caries
Can also consider chlorhexidine varnish as prevention
What do cochrane say about fluoridated milk?
Insufficient evidence
What do cochrane say about topical fluoride?
Used in addition to fluoride toothpaste show a modest reduction in caries compared to fluoride toothpaste alone
What prevention should we consider for all children?
Diet diary and sugar reducing advise
Fissure sealants for first permanent molars
Evaluation of fluoride sources
Twice daily toothbrushing, supervised under sevens
What toothpaste should 3+ children be using?
1350-1500 ppm, a pea sized amount
What should we be doing for all high risk children?
1350-1500 ppm toothpaste
Duraphat varnish 3-4 times yearly
Also add ether mouthwash or prescribed higher fluoride toothpaste
How do we prescribe high fluoride toothpaste?
10+ 2800 ppm
16+ 5000 ppm
What mouthwash can we give children able to rinse and spit (6+)?
Sodium fluoride mouth was daily 10ml= 0.05%
Sodium fluoride mouthwash weekly 10ml= 0.2%
What are the benefits of water fluoridation?
1ppm
50% overall reduction in caries. Particularly on interproximal and smooth surfaces
30% reduction in pits and fissure
Minimum amounts of mottling
How does fluoride work?
Low concentrations of fluoride in the saliva
Creation of fluorapatite crystals instead of hydroxyapatite
Reduces critical ph from 5.5 to 3.5
Resistance to acid dissolution
Reduces demineralisation
Predominant effect is topical
What’s in our fluoride toolkit?
Toothpaste Mouthwash Varnish Drops Tablets Gel Foam Glass beads
What did cochrane say about toothpaste?
Fluoride toothpastes are effective at preventing caries
Benefit only shown at 1000ppm and above
Dose response relationship
Potential for fluorosis i under 12
What did cochrane say about fluoride supplements?
Reduction in caries increment when compared to no supplement in permanent teeth
Effect unclear on primary teeth
Evidence overall is weak
When should we not use duraphat topical varnish?
Ulcerative gingivitis
Stomatitis
History of hospital admissions due to allergy, including asthma
What do cochrane say about topical fluoride varnish?
When used twice yearly:
DFMT prevented 46%
dmft prevented 33%
What is a toxic dose of fluoride?
Approx 1mg F/kg body weight causes gi upset
32-64 mg F/kg causes lethal poisoning
What happens with to much fluoride?
Blocks cell metabolism
Interferes with calcium metabolism
Nerve impulses and conduction
What are the signs and symptoms of fluoride over dose?
Nausea/vomiting/diarrhoea
Excessive salvation/tears/mucus/sweat
Headache
Generalised weakness
How do we deal with a fluoride overdoes?
Get a clear history
Check dose of fluoride against packet and see how much is left
Support vital signs
Management depends on dose. 5mg/kg+ send to a and e
As much milk as possible
What do we do with 5-15mg/kg overdose?
Send to a and e
Observe, support vitals, milk
Gastric lavage
What do we do with +15mg/kg over dose?
Send to a and e
Calcium gluconate Iv
Activated charcoal 1g/kg ever 4 hours and gastric lavage
Life support and cardiac monitoring
What is the mechanism of fluorosis?
Affect on enamel maturation by impairing mineral mineral acquisition
Greatest risk for centrals at 15-30 months
Coronal development completed at 6 years
How do we prevent fluorosis and overdoes?
Good history Examine packaging carefully Aim for topical not systemic Avoid critical age 0-6 Targeted use Good education for parents Prescribe maximum of 120mg of supplements at a time
Describe the anatomy of primary molars?
Thin, uniform thickness enamel Smaller crowns with marked constrictions Narrow occlusal table Broad contact areas Large pulps Large mesio buccal horn Thin pulpal floor Early radicular pulp involvement
What are the implication of primary molar anatomy on restorative dentistry?
Rapid caries progression
Short clinical crown makes matrix bands difficult
Need to restore broad contact point
Thin enamel with less tooth structure protecting the pulp
Mesio buccal pulp horn easily exposed
Long flared roots make pulp extinct difficult
Is ionisation radiation risk greater I’m children?
Yes. Below 10 the risk is 3x higher. Therefore radiation should be alarp
What is the first choice radiograph in children with both deciduous or mixed dentition?
Intra-orals
Oblique laterals and dpts may be needed in some situations
Do radiographs in children improve diagnostic yield?
Yes. 2-8x more than clinical examination alone
What are the radiographic recommendations for high caries risk children?
6 monthly bitewings until no new active lesions are apparent and the individual has entered another category
What are the radiographic guidelines for a moderate caries risk child?
Annual bitewings
What are the radiographic guidelines for a low caries risk child?
Bitewings every 12-18 months in the primary dentition and every 2 years in the permanent. More extended intervals can be used if there is explicit evidence of low risk
What percentage of children have radiographs with there GA referral?
10-12%
100% need them
What toothpaste should 0-3 year olds be using?
1000 ppm, a smear
What are the limitations of radiographs in children?
Cooperation issues
Anatomical difficulties: narrow arch, shallow palate
Occlusal caries may not be visible
May have overlap
What size film should be used I under 10s?
Size zero
With a tab not holder in under 7s
What is the distribution of disease in 5year olds?
70% have caries free dentition
Average dmft is 1.1
More than 86% of those with caries are untreated
What is the most frequent are of decay in 10year olds?
60% is interproximal
Wha are the factors influencing the choice of restorative material?
Patient factors: caries status, general health, para function, age, diet, cooperation
Tooth factors: teeth location, cavity design, pulp involvement, dentition, occlusal load, tooth quality
Operator factors: material properties, quality of finish, moisture control, expertise, anaesthesia
How do you manage approximal surface caries which is confined to enamel?
Encourage to arrest: topical fluoride, prevention advise, monitor
How do you manage approximal caries which is into dentine?
Restore: inter coronal/extra coronal restorations
What are Fuji 2 lc, Fuji 8, vitremer, photic fil?
Resin modified cement
Lower viscosity but similar strength to compomer
What are the advantages of resin modified GIC?
Adhesive Aesthetic Leach fluoride potentially Light cured Radioopaque Wear resistant
What are the disadvantages of resin modified cement?
Limited data
Leach fluoride?
Need good moisture control
What is poly acid modified resin?
Compomer
What are the advantages of compomer?
Adhesive Aesthetic Leach fluoride? Light cured Radiopaque
Disadvantages of compomer?
Multistage technique
Leach fluoride?
Moisture control
What are the advantages of GIC?
Adhesive
Aesthetics
Fluoride leaching
Good temporary
What are the disadvantages of GIC?
Long set Brittle Poor resistance to wear and erosion Radiolucent Moisture damage Only useful for less than 2 years in class 2
What is the evidence for amalgam in class 2s in primary molars?
A systematic review shows they would survive a minimum of 3.5 years.
However concerns over safety and aesthetics are making them less popular, despite a lack of evidence
What does the evidence say about GIC and rmgic in class 2 cavities in primary molars?
A systematic review says that GIC should not be used. There is evidence that rmgic is successful in small to moderate cavities. There is some evidence that conditioning dentine improves the success of rmgic
Which dental material would we temporise with in child dentition?
Conventional GIC= triage/Fuji 7
What permanent restorations would we consider in the primary dentition?
If a rubber dam can be placed we would use composite. If not we would place rmgic (Fuji 2) or compomer (dyract)
Indications for a ssc in the primary dentition?
Most interproximal cavities
2 or more carious surface
All pulp ally involved primary molars
Young children
What are the contraindications of ssc in the primary dentition?
Non-vital
Small occlusal cavity
Tooth soon to exfoliate
Parental preference
What are the frankl behaviour ratings?
1=definitely negative
4=definitely positive
Is there a difference between pulp regeneration in primary and permeate teeth?
Not really
Is there a difference between reparative potential of dentine pulp complex in primary or permed any teeth?
Reparative potential is greater than anticipated in primary teeth, if caries progression can be haunted before the pulp is overwhelmed
What is pulpal inflammation like in primary teeth?
Occlusal less so than proximal
What are the symptoms of a reversible pulpitis?
Provoked Disappears on removal of stimulus Shorter duration Relieved by analgesia Sharp pain
What are the symptoms of irreversible pulpitis!
Spontaneous Constant Long duration Not always relieved by analgesics Dull throbbing Sleep disruption
Do we vitality test primary teeth
No
Do we use ttp in primary teeth?
Yes. Distinguish food impact ion from peri-radicular pathology
When debating restore vs extract, what factors do we consider?
Medical
Social
Dental
Pulp status
What are some medical reasons we would retain a primary molar rather than extract?
Bleeding disorders
Patient at risk of GA
What are some medical reasons we would extract a primary molar rather than restore?
Immune compromised
Cardiac disorder such as ie risk
What pulp therapy would we consider in a vital pulp?
Pulp capping
Pulpotomy
What pulp therapy would we consider in a non-vital primary pulp?
Pulpectomy
Extraction
What is pulp capping?
A method of maintaining the vitality of the pulp by placing a dressing either directly on to an exposed pulp or onto residual dentine over nearly exposed pulp. Aims to protect pulpal health
What medicaments is commonly placed in a direct pulp cap?
Calcium hydroxide
What are the aims of a direct pulp cap?
To promote dentine bridge formation over exposure and to preserve vitality
Is direct pulp camping successful?
In permanent teeth yes
Not recommended in primary molars as treatment is rarely iatrogenic
What are the aims of an indirect pulp cap?
Arrest caries
Allow for formation of reactionary dentine and remineralisation of dentine
Promote pulp healing and preserve vitality
What are the indications for an indirect pulp cap?
deep carious lesion
No signs/symptoms of pulpal pathosis
No radiographic pathology
What is a pulpotomy?
The removal of the coronal part of the pulp tissue, assuming this part is irreversibly inflamed
Done in vital, asymptomatic/transient pain, no radiographic pathology
Does pulpotomy use a rubber dam?
Yes
What are potential pulpotomy medicaments?
Ferric sulphate- haemostatic agent. Agglutination I blood proteins .Reaction with blood forms a barrier
Why don’t we use calcium hydroxide in pulpotomy?
High failure rate
Internal resorption
Why don’t we use formocresol in pulpotomy?
Safety concerns
Why don’t we use MTA in pulpotomy?
Expensive and not readily available
What is mih?
Hypo mineralisation of systemic origin of one or more of the four permanent molars, as well as any associated or affected incisors
What is the prevalence if mih?
3.6-25%
How does mih present?
Affects one or more of permanent molars Demarcated patches White-brown, cream Post eruptive breakdown Missing sixes Heavily restored abnormal restorations Calculus
What are the differential diagnosis’s of mih?
Fluorosis
Ameligenesis imperfecta
Turner tooth
Idiopathic hypo mineralisation
What happens in amelogenesis?
Odontoblasts secrete type 1 collagen Ameloblasts differentiate Secrete enamel proteins Change shape Cause mineralisation
What happens during the secretory phase of amelogenesis?
Defines the form of the tooth
Deposition of organic matrix plus small thin crystals
Incremental growth in thickness
Not a continuous process
What causes enamel hypoplasia?
Disruption in secretory phase
Early in development
Small pits and grooves
Gross enamel surface defect
What is the maturation phase of amelogenesis?
Establishes the quality of the tooth Degradation of the organic matrix Mineralisation Ameloblasts move ca2+ and po4 Process continues post eruption Apoptosis of the ameloblasts
Describe enamel hypomineralisation
Disruption in the maturation phase Poor mineralisation of matrix Later in development White/brown opacities Normal thickness but more quality
How does enamel hypo mineralisation appear down the microscope?
Altered ca/p ration
Less distinct enamel rods
Bacterial penetration of enamel
Lower hardness
Is mih linked to chemical exposure?
Evidence for exposure to environmental chemicals is weak
It is connected with breast feeding
Weak evidence of an association with fluoride
Do peri-natal problems increase mih prevalence?
Malnutrition, maternal health, birth problems
Many confounding factors
Weak evidence
Do common childhood illnesses implant on mih?
No clear evidence
Weak evidence for chronic problems
What are the options for repairing the aesthetics on mih incisors?
Micro abrasion Etch bleach seal Bleach Composite Bleach and composite
What do we do in etch bleach seal?
60s etch
Bleach 5% NaCL, 5-10 mins
Reetch and fissure seal
Is caries in the first permanent molars common?
Yes, over 50% of children over 11 have it
Occlusal surface 6s accounts for 90% of caries in children
When managing first permanent molars we consider what?
Patient factors
Dental factors
Orthodontic factors
What radiographs do we need to assess patient factors I. The management of permanent molars?
Dpt to examine the other teeth, some yet to come through
When is the best time to extract a first permanent molar?
Root bifurcation of the 7 forming
8-10 years
Which is worse, late extraction of 6 or early?
Late
What is the preferred restorative technique in a fpm which is vital but with deep caries?
Indirect pulp capping
Not direct or pulpotomy due to long term prognosis
What are the issues with ssc in fpm?
Technically more challenging
La often required
Monitor eruption of 7s as potential for impact
Occlusion
What anatomy will affect an idb in a child?
Children’s ascending Ramus is shorter and narrower anterior posteriorly
Decreases depth of needle penetration
Describe articane
4%
1:100000 adrenaline
Which teeth are used for a grubby score?
Upper right six
Upper left one
Lower left six
Lower right one
What are the gum scores?
0= healthy pink and stippled 1= marginal reddening, no swelling 2= red with swelling 3= bleeding on gentle probing
What are the signs of a faint?
Nausea Pallor Thready pulse Loss of consciousness Cyanosis Fits
How do we manage a faint?
Supine
Maintain airway
Give oxygen
What are the signs of hypoglycaemia?
Trembling Sweating Hunger Truculence Disorientation Slurring Loss of consciousness
How do we treat hypoglycaemia?
Conscious= glucose drink 10-20g
Unconscious= glucagon 1mg intra muscularly
Airway and oxygen
Transfer to hospital
How do we manage an epileptic fit?
Protect from injury during
Maintain airway and oxygen
In status epilepticus give midazolam buccal liquid 10mg/ml
What kind of la is articaine?
Ester, processed by plasma cholinesterases
In what form is la active?
Hydrophilic ionised form
What’s the half life of lidocaine?
90mins
45-60 min pulpal duration
What’s te half life of articaine?
20mins
Pulpal duration 75mind
Which areas will be innervated by the posterior superior alveolar nerve?
All of the 8 and 7
May not get the mesio buccal root of the 6
What does the nasopalatine nerve innervate?
Palatal gingival 3-3
What does the greater palatine nerve innervate?
Palatal gingival 8-4
What are the landmarks for an idb?
Thumb on the coronoid notch
Pterygomandibular raphe
What is alveolar osteitis?
Dry socket
Usually post extraction
Inflammation of the alveolar bone
Thought to be loss of blood clot leaving alveolar bone exposed to the oral environment
What is the incidence of dry socket?
1-20% of routine extractions
Up to 30% of third molar extractions
What are the symptoms of dry socket?
Occurs a few days after extraction Painful Bad taste and odour Not relieved with analgesics No pyrexia No swelling or infection
What factors influence dry socket?
Smoking Oral contraception Local infection Compromised patient Altered bone metabolism Excessive trauma
How do you manage dry socket?
Examination - consider X-ray for retained root
Irrigation of socket with saline or chlorhexidine
Obtudant pack=
Alveogyl resorbable
Zinc oxide eugonol pack requires removing
Bismuth sub nitrate and iodoform paste bipp
Lidocaine based gels
What is alveogyl?
A brown fibrous paste which contains the following per 100g
25.7g butamben
15.8g iodoform
13.7g eugenol
Also includes other ingredients like olive oil, spearmint oil and sodium lauryl
What are the signs of adrenal insufficiency?
Pallor
Rapid thready pulse
Decreased bp
Loss of consciousness
How do we manage adrenal insufficiency?
Supine
Maintain airway and oxygen
Hydrocortisone 100mg Iv/Im
No improvement then call ambulance
What are the signs of anaphylaxis?
Sob Flushing Itching Pallor Loss of consciousness Cyanosis Very weak pulse Decreased bp Oedema
How do we manage anaphylaxis?
Supine Airway and oxygen 999 Adrenaline 0.5mls 1:1000 Im 1mg/ml Repeat at 5minute intervals
How do we manage mi?
Airway and oxygen Aspirin 300mg orally Gtn 999 Bls if needed
How do we manage asthma?
Maintain airway and oxygen Salbutamol inhaler 100 micrograms per puff Salbutamol nebuliser 5mg Hydrocortisone 100mg Iv im Repeat as required Consider adrenaline
What rate of chest compressions are needed?
100-120/min
What’s the molecular structure of la?
Aromatic ring - lipophillic
Intermediate linkage - ester or anise
Terminal amine - hydrophilic portion
What kind of la is lidocaine?
Amide, processed by the liver
Does dry socket need antibiotics?
Not thought to influence
Some evidence they may work prophylacticly
Evidence to support use in the immunocompromised patient
What local measures do we use for bleeding?
Move to suitable clinical area Good light Auction Assistance La with vasoconstrictor Sutures Haemostatic acids e.g. Surgicel/fibrin blocks Bone wax
What are the adult doses of amoxicillin for dental infections?
500mg every 8 hours
Double in serve infections
What is the amoxicillin does in children following a dental infections?
1-1 year old= 62.5mg every 8 hours
1-5 years= 125mg every 8 hours
5-18 = 250g every 8hours
What do we need from a radiograph pre endo?
At least one good peri apical
Treatment tooth centrally located
At least 3-4mm peri radicular tissue visible
Taken with a film holder to minimise distortion
Why do we need straight line access to root canals?
Because without it the files will deflect and a groove will be filled down the labial wall of the canal
Should an access cavity be undercut?
No
What shape should the access cavity be?
Dependant on the tooth.
Incisors have three pulp horns so have a triangular access cavity
Canines and premolars have 2 horns so an oval access cavity
How can we locate root canals?
Knowledge of pulpal anatomy Information from radiographs Magnification techniques Transillumination with white light Canal probe e.g. Dg explorer Fine endodontic hand instruments
When do we apply rubber dam in endo?
Once the pulp chamber is breached
What do we do in decayed teeth where isolation can’t be achieved for endo?
Restore them for efficient isolation
How can we improve a rubber dam seal?
Ultradent oraseal caulking agent
What shape canal do we want in endo?
Narrowest apically
Widest part coronally
Gradual outward flare
How do we measure working length?
Tables of averages
Apex locator
Radiography
How does an apex locator work?
Measures electrical resistance with direct alternating and high frequency currents
Measuring voltage gradients
Calculating ratio between impedances
What are the problems with apex locators?
Wet canals in absolute al machines:
Hydrochloride
Pus
Tissue exudate
Heavily restored crowns:
Amalgam
Gold inlay
Poor contact with lip electrode
How do we measure a radiographic working length?
Measure from fixed reference point to radiographic apex, then minus 1mm
What is the design of k files?
Tapering square cutting from the corners
Steel
Square on top
What is the design of hedstrom files?
Christmas tree shaped. Tapering circle
Steel
More aggressive than k files
What is the design of pro taper files?
Nickel titanium with elastic memory
Spongy grip
More expensive
What is the diameter of a gates gladden but in hundredth of a mm?
20 (gg+1) +10
How do we do orifice enlargement?
A size 10k file is passed gents to apical constriction to check patency
Using the largest hedstrom which will pass 3mm of the canal orifice is used circumferentially around the canal periphery, cutting on the out stroke
Progressively smaller headstrong are used to penetrate further down the canal
Instruments should only be taken to te beginning of the curve
Why do we do orifice enlargement?
Removes heavily infected materials
Improves access to apical third of the canal
Improves irrigation
Reduces effective curvature of the canal
What is ISO?
International standards applied to endodontic files
Standardised sizing related to diameter 1mm from tip.
Standardised length of working part
Standardised taper
What are the three available file lengths?
21, 25, 31
What is the cutting length on a file?
16mm
What is the standard instrument taper?
2%
What is the width at the tip of a file?
The number on the file divided 100
E.g. Size 25= 0.25
What are the endodontic instrument techniques?
Step back and crown down
What are the endodontic filing techniques?
Watch winding
Balanced force
Longitudinal circumferential
What is the main use of a modified step back technique?
Large canals
Most often anterior teeth
What is a modified step back technique?
The coronal aspect is opened up first before creating an apical terminal stop and flaring backwards to original flare
What is a crown down technique?
The canal is instrumented from the coronal aspect to the terminus
How do we create an apical stop?
Using successively larger instruments
Use balanced force and anticurvature filing
How many instruments are required to make an apical stop?
9
Need to recapitulate with a smaller file to clear debris
How do we step back?
Step back at 1mm intervals with each a successively larger file
Recapitulating in-between with the master file
How many instrument changes are required to step back?
14
What are the advantages of balanced force technique?
Superior shaping
File remains central within the canal
Less debris pushed apically
What cautions need to be taken with balance force?
Flute cleaning
Copious irrigation
Disregard damaged instruments
What is phase one of balanced force filing?
Power
Place file until it binds
Advance file by clockwise rotation of 60 degrees
What is phase two of balanced force?
Control
Apply apical pressure
Rotate file by 120 degrees in anticlockwise direction
What are some errors relating to canal preparation?
Incomplete debridement
Lateral perforations
Apical perforations
Blockage of canals
Ledging
Apical zipping due to inappropriate rotations of instruments
Elbow formation due to inappropriate precurving of instruments
When would we use longitudinal circumferential filing in step back?
For large irregular shaped canals
When balanced force is inappropriate as files would be to loose
What are the advantages of an anticurvature filing technique?
Avoids strip perforations
Uses a 3:1 filing ratio
Precurved k type files
How do we do a anticurvature filing technique?
Files are bent around mirror handle
Use push pull longitudinal filing technique
Never rotate
What are the ideal properties of a canal irrigant?
Non irritant Bacteriacidal Dissolve organic material Remove inorganic material Non staining to dentine Lubrication of instruments
Describe sodium hypochlorite as an irrigant
0.5-5% solution
Antibacterial
Dissolves organic
Non irritant to vital tissues at low concentrations
What is a chelating agent?
EDTA
Breaks down inorganic debris
Lubricant
When used with sodium hypochlorite causes effervescence which assists cleansing of those parts of the canal which are u instrumented. This is due to nitrogen, hydrogen and oxygen release
What are the advantages of chlorhexidine as a canal medicament?
Low toxicity
Broad spectrum if activity
Substantivity due to bicationic
What is the cutting length on a pro taper file?
14mm
What are the advantages of pro taper files?
Better in right canals
Fewer files needed
Engage a smaller area of dentine which reduces torsional loads, file fatigue and potential for separation
Balanced pitch and helical angle
Describe the design of a pro taper file
Convex triangular cross section Nickel titanium Stress induced phase change 3-5 times the elastic flexibility of stainless steel Decreased ledging and transportation
Describe sx alternative orifice enlargement
Enlarge dentine by gently turning clockwise until file is snug
Disengaged by rotating counterclockwise 45-90 degrees with pressure I ensure the file doesn’t wind out of the canal
Re establish patency with size 10k file and watch winding. Repeat with size 15k and size 20, using balanced force with size 20
Rotate the handle clockwise whilst withdrawing to ensure removal of debris
Following orifice enlargement, what are the next steps of crown down?
Using s1 file to full length of the canal
Use s2 to the full length of canal
Check patency with 20k
Use f1 and reinstrument with 20k. Stop if snug
What precautions do we take between endodontic appointments?
Place a medicament and a temporary restoration to prevent reinfection
What does ledermix contain?
Demethylchlorotetracyxline
Triamcinalone acetonide
When should we use ledermix?
Acutely inflamed vital pulp where analgesia can’t be obtained
In pulpal exposure with insufficient time for root canal
What is the usual interappointment medicament?
Calcium hydroxide
How does the hydroxide in calcium hydroxide work?
Ph 12.5 Bacteriacidal Effective solvent to organic material Premises connective tissue repair Promotes hard tissue genesis Neutralises acids in areas of resorption
What are options for an interappointment temporary restoration?
GIC
Zinc oxide eugenol
What does it mean if the gp cone is too long?
Incorrectly calculated working length
Gp is to small and has pushed through he terminus
What does it mean if the gp come is too short?
Incorrectly calculated working length
Debris is blocking the terminus
To large of a master point
Why do we obturate?
Prevent microorganisms from entering and reinfecting the root canal
To prevent tissue fluids from percolating back into the canal system and acting as a culture medium for residual bacteria
Produce a 3d hermetic seal to prevent microleakage
Apical seal and coronal seal
What are the ideal requirements prior to filling a canal?
Dry canal
Absence of pain and other symptoms
Signs of resolution of infection -reducing Radiolucency
Absence of signs of residual infections - fistula or sinus
Reduction in mobility
In rct, what are the potential problems with a smear layer?
May harbour microorganism
May create an avenue for leakage of microorganism
May act as a substrate for proliferation
How do we remove a smear layer?
EDTA and sodium hypochlorite
10-55% citric acid followed by rinsing with sodium hypochlorite
What are the functions of a root cabal sealer?
Cements the core material into the canal Helps fill voids Lubricant Bacteriacidal Thermal insulator on placement if gp
What are the ideal characteristics if a sealer?
Non irritating to peri apical tissues Hermetic seal Insoluble in tissue fluids Dimensionally stable Radiopaque Bacteriostatic Non staining to dentine Sticky with good adhesion to canal walls Easily mixed and removed
Discuss zinc oxide eugenol sealers
Form a weak porous material when set Decompose in tissue fluid Cytotoxic Extended working time available Most popular 92-95% success
Describe calcium hydroxide sealers
Developed on the assumption that they would stimulate healing and hard tissue formation
Setting ability similar to Zoe
Discuss resin sealers
Good sealing and adhesive properties
I ritual inflammatory reaction
Antibacterial properties
Less popular due to expense and poor handling properties
Discuss GIC sealers
Ability to adhere to dentine
Initial inflammatory response which subsides
Patch sealing
What length should the finger spreader be?
2mm short of working length
What are common errors in obturation?
Inaccurate placement of master point Lack of snug fit at the apex Use I incorrect spreaders or points Extrusion of file or sealant through apex Use of excessive condensation pressure Inadequate coronal seal
Why might la fail in an infected patient?
Increased vascularity removes the solution
Acidic conditions impedes active component
The prostaglandins increase the threshold of nerves
How do we manage la problems in an infected patient?
Give block injection
More la or more concentrated solution
Intraligamental
If none of the above work prescribe antibiotics and wait 3-4 days for acute inflammation to become chronic
What do upper straight forceps look like?
Two arms
Not bent at the neck
What do upper premolars forceps look like?
Two arms
Bent, but not left or right
Fairly thin
What upper molar forceps look like?
Like premolars, but thicker and less bent
Left and right differ - beak to cheek
What do lower root forceps look like?
Bent to the side
Two arms with no grooves
Narrow
What do lower molar forceps look like?
Bent to the side
Grooved beaks
Thick
What do lower cow horns look like?
Similar to lower molars
Much thinner, have point not beaks
How many contact points are needed during an extraction?
2 points of contact between root and forceps blades
How do forceps enable delivery?
Expanding the socket
Wedging blades of the forceps between the root and bony socket causing displacement of conical root from socket
Due to forcep design, where is the force delivered to the tooth?
Apically
Where are the blades of upper forceps?
Inline with the handle
Where are the blades in lower forceps?
At right angles to the handles
What movement do you do to extract upper incisors?
Rotation due to conical root
What movement do you do to extract upper 3-8?
Bucco palatal
What movement do you do to extract lower incisors and canines?
Labial then rotations
What movement do you do to extract premolars?
Rotations, and where roots curved addition buccal and lingual movements
What movement do you do to extract lower molars?
Buccal lingual pressure
Deliver buccally
In what order should we do multiple extractions?
Start with lowers, and more posteriorly
Unless we need to extract a more anterior tooth to get better access
Extract painful tooth first
What is the difference between a liner and a base?
A liner is applied in a thin layer into dentine. A base is thicker and used to replace some missing dentine
What is the purpose of a liner?
Mainly used to seal dentine tubules to reduce pulpal injury due to microleakage
Thermal barrier especially in metallic fillings
A chemical barrier
An electric barrier
What is a luting material?
Used to retain or hold restorations in place
What properties should a luting material have?
Low initial viscosity to allow flow and proper seating
Low solubility
Describe the composition of zinc phosphate?
Powder: zinc Oxide and other metallic oxides
Liquid: phosphoric acid 45-64%
What is de trey zinc?
Zinc phosphate cement
How do we mix zinc phosphate?
No set ratio
Mixed on cooled slab
What are the properties of zinc phosphate?
No bonding affinity do tooth, metal or ceramic
Phosphoric acid roughens surface providing some microretention
Okay working time
Film thickness suitable for luting
Small be significant water solubility
May irritate pulp if used as a limit due to low ph (2-4)
Set material is opaque
What is poly f?
Zinc poly carboxylate
What is the presentation of poly f?
Powder and liquid
Powder: zinc oxide
Liquid: poly acrylic acid
Or
Powder:zinc oxide and freeze dried poly acrylic
Mix with water
Mix one scoop to two drops for luting
2:2 for temp
What are the properties of zinc polycaroxylate?
Acidic, but less so than zinc phosphate
Adhesive bond with enamel, dentine and non-precious metal
Weak bond with gold and no bond with porcelain
Strong bond with ss
What is aqua cem?
GIC cement
What is the composition of GIC luting cement ?
Powder: glass (sodium aluminosilicate glass) and 20% caF
Liquid: poly acid
2 scoops:4 liquid
Are particles of GIC bigger or smaller for luting and lining?
Smaller
What are the properties of GIC?
Same adhesive properties as poly f
More translucent than zinc oxide
Can withstand amalgam condensing
Thermal diffusivity close to that of dentine
What are resin luting cements?
Lightly filled composites with small sized filler particles to ensure thin film thickness
Strong, less soluble and more aesthetic than other cements
What is panavia f?
Resin Luton cement
What is kalzinol?
Zinc oxide eugenol
What is the composition of zinc oxide eugenol?
Powder: zinc oxide and zinc acetate
Liquid: eugenol and olive oil
5:1 mixed in glass slab
What are the properties of kalzinol?
Adequate working time and rapid setting Eugenol has soothing effect on the pulp High solubility so not suitable for luting unless temp Effective thermal barrier Thermal diffusivity similar to dentine
What is life?
Calcium hydroxide cement
What is the composition of calcium hydroxide?
The base is calcium hydroxide (50%), zinc oxide (10%) and sulphonamide (40%)
The catalyst is 40% glycol salicylate with varying amounts of titanium dioxide and calcium sulphate
What are the properties of life?
Weak
High solubility
Difficult to apply in thick sections so only used as lining
Highly alkaline so antibacterial and stimulates reparative dentine
What four things does caries need to develop?
Bacteria
Substrate
Tooth
Time
What kind of caries does actinomyces cause?
Root caries
What kind of caries does lactobacillus cause?
Progression of deep lesions
Where is the translucent zone in an early caries lesion?
The outer most later surrounding the body of the lesion.
Where is the dark zone in an early caries lesion?
Just before the translucent zone
Which is the most porous are of an enamel caries lesion?
Centre of body is 25% pore volume
What is happening at te advancing front of dentine caries?
Demineralisation but not infection yet
What is happening in the zone of penetration in dentine caries?
Tubules penetrated by bacteria
Describe the appearance of an arrested carious lesion
Matt due to porosity
Soft and leathery texture
What are the defence mechanisms of the dentine pulp complex
Tubular sclerosis
Reactionary dentine
Inflammation of the pulp
Pulpitis symptoms
What are the ideal characteristics of a restorative material?
Radio-opaque Tooth coloured Adhesive to tooth No volume change on setting Provide protection from Recurrent caries Have adequate strength Insoluble and non-corrodible Non toxic and non irritant Resist plaque formation Wear rate similar to enamel Coefficient of thermal expansion similar to tooth structure Thermal diffusivity similar to tooth Have low water absorption
What is a class 1 cavity?
Caries affecting pits and fissures
What is a class 2 cavity?
Posterior interproximal
What is a class 3 cavity?
Anterior interproximal
What is a class 4 cavity?
Caries affecting the approximal surface of anterior teeth and the Incisal edge
What is a class 5 cavity?
Caries effecting the cervical surfaces
Other than caries, why might we do a restoration?
Trauma
Erosion/abrasion
Enamel hypoplasia
Masking discolouration
What is an e1 lesion?
Caries confined to outer 1/2 of enamel
What is an e2 lesion?
Caries confined to inner 1/2 of enamel
What is a d1 lesion?
Caries 0.5mm into dentine
What is a d2 lesion?
Caries more the 0.5mm into dentine but more than 0.5mm from the pulp
What is a d3 lesion?
Caries within 0.5 mm of pulp
Are bite wings useful to diagnose class 2 lesion?
Increase diagnosis of interproximal lesions 4 fold when compared to clinical examination alone
Are laser fluorescence machines used?
Only for occlusal lesions with visual inspection
How long does it take for an interproximal lesion to reach the adj?
3-4 years in children
Maybe as long as 6years in adults
When do we recommend interproximal intervention?
When lesions extend more than 0.5mm into dentine
Indications for posterior composites?
Small-moderate class 2
Metal allergy
Where unsupported enamel may be strengthened
Where it’s not possible to obtain retention for a non-adhesive material
What are the contraindications to posterior composite restorations?
High caries activity and poor oh Inadequate isolation Multiple large restorations with cuspal contact Bruxism Allergies to resin
What is the survival are of a gold inlay after 25 years?
84%
What do ears involve?
The rebuilding of cusps
Provision of auxiliary retention
Postpone cast restoration
What are the advantages of ears over cast restorations?
Less invasive
Less expensive
Less time
How do we provide auxiliary retention?
Cavity design features
Pins
Adhesives
Posts
What is retention?
Features of a cavity preventing withdrawal of the restoration in the long axis of the prep
What is resistance?
Features preventing dislodgement of the restoration under other forms of loading
How should we create slots?
A depth no greater than 1mm
A width no more than the instrument used
Sharp internal form which increase stresses within the tooth material- for resistance form
Do pins provide retention or resistance?
Both!
What are the types of pins?
Cemented pins
Friction grip pins
Self threading pins- more retentive
What influences pin retention?
Larger diameter pins are more retentive
Depends on resilience and firmness of dentine
Only place in healthy dentine
What are the disadvantages of pins?
Pulp exposure
Root perforation
Cause stresses in the tooth - except cemented
Cracks I’m dentine surrounding the pins
What is the evidence for adhesives used with amalgam?
There isn’t evidence for or against them
In what type of patient are ears likely to fail?
Old
What are the technical failures of ears?
Defective contact point/over hangs
Non retentive
Fractured restoration - doesn’t necessarily come out. Could stay and facilitate secondary caries
What are inlays/onlays made from?
Gold alloys
Composites
Ceramics
Zinconium oxide
What are the indications for an inlay/onlay?
Large restoration Endodontic tooth Teeth at risk of fracture Wide open contacts and occlusal plane correction Prosthodontic abutment Dental rehabilitation Sub gingival lesion
Contraindications of an inlay/onlay?
Young dentition with large pulp chambers Developing and deciduous teeth Aesthetics Poor oh Small restorations
What are the advantages of inlay/onlays?
Strength
Biocompatibility
Low wear
Control of contours and contacts
What are the disadvantages of inlays/onlays?
Extensive tooth prep Cemented restoration, discrepancy and microleakage Abrasive and slitting forces on natural teeth Galvanic currents Number of appointments Cost Temporary required Techniques sensitive
What are the feature of an inlay/onlay prep?
Undercut free
Maximum height
Minimum taper
Single path of insertion
How much chlorhexidine is in corsodyl?
0.2%
How much fluoride is in duraphat varnish?
22600 ppm
What are the 4 safety benefits of rubber dam?
Control root canal irrigants
Barrier between operator and oral fluids
Control and protection of soft tissues
Prevents inhalation or swallowing
What the advantages of rubber dam for patient management?
Avoids need for continued rinsing
Improves access and vision
Provides gingival retraction
reduces operating time
What are the disadvantages of rubber dam?
Gingival damage Fractures porcelain restorations Fractured heavily restored teeth Inhalation of clamps Contact allergy
What’s the difference between bland and retentive claps?
Bland claps grab teeth above the gingival margin
Retentive claps grasp below, they are angled downward accordingly
What is the correct placement of a rubber dam clamp?
The bow of the clamp is distal
The clamp has 4 anchorage points
The clamp grips below the maximum bulbosity
