ORE Part 1 cheat sheet

Enamel is approximately 96% inorganic (hydroxyapatite) by weight; dentine is approximately 70% inorganic, 20% organic (mainly type I collagen) and 10% water.

A-delta nerve fibres are myelinated and mediate sharp, well-localised dental pain; C fibres are unmyelinated and mediate dull, poorly localised pain.

Cardiac output = heart rate × stroke volume; normal resting cardiac output is about 5 L/min.

A local anaesthetic pKa above tissue pH means inflamed acidic tissue reduces the unionised base fraction and lowers anaesthetic efficacy.

Parathyroid hormone raises plasma calcium by increasing bone resorption, renal calcium reabsorption and renal 1-alpha-hydroxylase activity.

Osteoclasts are multinucleated cells that resorb bone; osteoblasts synthesise osteoid, which mineralises after a lag phase.

Resting whole salivary flow is about 0.3-0.4 mL/min; stimulated whole salivary flow is about 1.5-2.0 mL/min.

Warfarin inhibits vitamin K epoxide reductase; heparin potentiates antithrombin III.

The mandibular division of the trigeminal nerve (V3) supplies sensation to the lower teeth, chin and lower lip and motor supply to the muscles of mastication.

Conventional glass-ionomer cement bonds chemically to enamel and dentine through polyalkenoic acid and releases fluoride over time.

Volumetric polymerisation shrinkage of dental composite is about 2-3%; shrinkage stress rises as the C-factor (bonded to unbonded surface ratio) increases.

Enamel is usually etched with 37% phosphoric acid for 15-30 seconds; dentine etch times are shorter, typically 10-15 seconds.

Endodontic working length is conventionally set 0.5-1.0 mm short of the radiographic apex.

Sodium hypochlorite dissolves organic pulp tissue and has antimicrobial activity; EDTA chelates the inorganic smear layer.

Ante's law states that the total root surface area of abutment teeth must equal or exceed that of the teeth being replaced.

A ferrule of 1.5-2.0 mm of parallel axial dentine improves the fracture resistance of a post-retained restoration.

An ideal crown-to-root ratio is about 1:2; 1:1 is often regarded as the minimum for a conventional fixed prosthesis.

BPE codes 0, 1 and 2 require no full periodontal charting; codes 3 and 4 indicate that full periodontal assessment and charting are required.

Clinical attachment level = probing depth + gingival recession, or probing depth − gingival enlargement.

Smoking and poorly controlled diabetes are major modifiable risk factors for periodontitis.

Plaque-induced gingivitis is reversible and does not cause attachment loss; periodontitis involves clinical attachment loss.

Inferior alveolar nerve injury risk is highest in deep mandibular third molar surgery and with lingual flap retraction.

Dry socket (alveolar osteitis) presents with severe pain and an empty socket 2-4 days after extraction.

NICE guidance does not recommend routine antibiotic prophylaxis for infective endocarditis before dental procedures; cardiology advice is sought for exceptional high-risk patients.

Maxillary sinus pneumatisation can bring the sinus floor close to maxillary molar roots, increasing the risk of oro-antral communication during extraction.

Lidocaine with adrenaline has a maximum dose of about 4.4 mg/kg, with an absolute adult cap of 300 mg.

Oral squamous cell carcinoma most commonly arises on the lateral border of the tongue and floor of the mouth.

Leukoplakia is a clinical diagnosis of a predominantly white lesion that cannot be characterised as any other definable lesion.

Oral lichen planus classically shows reticular white Wickham striae with a bilateral buccal distribution.

Pemphigus vulgaris is an IgG-mediated intraepithelial blistering disease with a positive Nikolsky sign; mucous membrane pemphigoid is subepithelial.

A persistent oral ulcer or red/white lesion present beyond 2-3 weeks is an indication for biopsy.

Ameloblastoma typically presents as a multilocular soap-bubble radiolucency in the posterior mandible.

Odontogenic keratocyst has a high recurrence rate and may show a scalloped radiolucent outline; it can be associated with naevoid basal cell carcinoma syndrome.

Paralleling technique with a film holder reduces geometric distortion and gives reproducible periapical images.

Cone-beam CT delivers a lower dose than multislice CT but a higher dose than a panoramic radiograph.

Primary teeth usually begin to erupt at about 6 months, with mandibular central incisors first; the full deciduous dentition of 20 teeth is complete by about 2.5-3 years.

Fluoride varnish contains 22,600 ppm fluoride (5% sodium fluoride) and is typically applied twice yearly to caries-prone children in UK programmes.

Fluoride toothpaste strength is commonly 1,000-1,500 ppm for children, with 2,800 ppm reserved for high-risk children over 10 years under supervision.

Angle Class I occlusion: the mesiobuccal cusp of the upper first molar occludes in the buccal groove of the lower first molar.

Class II division 1 malocclusion shows increased overjet with proclined upper incisors; Class II division 2 shows retroclined upper central incisors.

The Index of Orthodontic Treatment Need combines a dental health component graded 1-5 with an aesthetic component graded 1-10.

DMFT counts decayed, missing due to caries and filled permanent teeth; dmft is the equivalent index for the primary dentition.

Fissure sealants are indicated for deep pits and fissures in caries-prone teeth, especially first permanent molars, when enamel is sound or incipiently carious.