DN9 - provide chairside support during the provision of fixed and removable prostheses

Question 1

STAGES FOR FIXED AND REMOVABLE PROSTHESES:

Answer 1

there are three stages to fixed and removable protheses:

• preparation, temporisation and and fitting of fixed protheses
• construction and fitting of removable protheses
• fitting, monitoring and adjusting of fixed and removable orthodontic appliances

Question 2

WHAT ARE FIXED PROTHESES?

Answer 2

fixed prostheses are the tooth restorations or replacements that are cemented within, or onto, a tooth and include the following protheses:

• TEMPORARY OR PERMANENT CROWN - a cap or shell-like device made to cover three-quarters to the whole surface of a single tooth
• TEMPORARY OR PERMANENT BRIDGE - two or more crown-like units joined together as a single device, at least one of which is to replace a missing tooth
• VENEER - a facing made to fully cover the labial surface of a tooth
• INLAY - an insert of a tooth cavity that has been constructed in a laboratory

Question 3

WHAT ARE REMOVABLE PROTHESES?

Answer 3

removable protheses are all types of dentures - appliances that are made in the laboratory in various stages to replace missing teeth. they can be removed from the mouth by the patient and reinserted again easily, without the use of cements.
FULL DENTURE - when there are no teeth left in the jaw, it is said to be edentulous and the artificial replacement is called a full or complete denture
PARTIAL DENTURE - if some teeth are still present, the replacement is called a partial denture

Question 4

WHAT ARE ORTHODONTIC APPLIANCES?

Answer 4

orthodontic appliances are used to allign teeth within each arch to correct the occlusion between the two jaws. they are either fixed appliances, which are cemented in a similar way to fixed protheses, or they are removable appliances that are constructed in a similar way to removable protheses, but do not require the intrim construction stages for their completion. however, once fitted they do require regular monitoring and adjustment as the treatment progresses.

Question 5

FOR A FIXED PROSTHESIS APPOINTMENT, THE PROCEDURE WILL BE ONE OF THE FOLLOWING OPTIONS:

Answer 5

• crown preparation or crown fitting( temporary or permanent)
• bridge preparation or bridge fitting (temporary or permanent)
• veneer preparation or fitting
• inlay preparation or fitting

Question 6

FOR A REMOVABLE PROSTHESIS APPOINTMENT, THE PROCEDURE WILL BE ONE OF THE FOLLOWING OPTIONS:

Answer 6

• first or second impressions, with or without shade taking
• occlusal registration, with or without shade taking
• try-in or re-try
• fitting

Question 7

FOR AN ORTHODONTIC APPLIANCE, THE PROCEDURE WILL BE ONE OF THE FOLLOWING OPTIONS:

Answer 7

• working model impressions for removable appliance construction
• removable appliance fitting
• fixed appliance bonding
• fixed or removable appliance monitoring and adjustment
• fixed appliance debonding and fit retainer
• removable retainer fit

Question 8

INSTRUMENTS, MATERIAL AND EQUIPMENT REQUIRED FOR FIXED PROTHESIS PREPARATION:

Answer 8

DIAMOND BURS - tapered so that no undercuts are produced on the prepared tooth or teeth, otherwise the fixed prothesis will not seat fully on the tooth
AIR TURBINE HANDPIECE - for use with the burs during preparation
RETRACTION CORD - cord soaked in an astringet solution that is then packed into the gingival crevice to cause shrinkage of the gingiva away from the prepared tooth - this provides a definitive tooth margin which is reproduced in the impression and also the cast model
IMPRESSION TRAYS - variety of plastic or metal boxed trays, sized to fit fully over the dental arch - upper and lower styles. also triple tray system.
CROWN-FORMER - pre-formed plastic or polycarbonate tooth-shaped formers, in a variety of sizes and availiable for each tooth shape- required when preparing for crowns or bridges
BEEBEE CROWN SHEARS - short beaked shears for cutting and shaping the margins of temporary crowns
SHADE GUIDE - shaded teeth in holder, to determine the required shade of the prosthesis by comparing each example to the adjacent teeth and determining the best match available
POST SYSTEM - required if a post crown is being provided

Question 9

IMPRESSION MATERIALS FOR THE WORKING ARCH, THE OPPOSING ARCH, AND TEMPORARY CEMENT:

Answer 9

• WORKING ARCH:
• elastomer material with mixing gun, mixing machine or waxed pad and spatula
• OPPOSING ARCH:
• alginate material with bowl and spatula, or mixing machine
• TEMPORARY CEMENT:
• zinc oxide and eugenol-based temporary luting cement to hold the temporary crown or bridge in place
• glass ionomer-based cement for veneer tooth coverage
• temporary filling material for inlay preparation
• appropriate mixing pad/glass slab and spatula for each

Question 10

INSTRUMENTS, MATERIAL AND EQUIPMENT REQUIRED FOR FIXED PROTHESIS FITTING:

Answer 10

FINE ARTICULATING PAPER - to accurately check the occlusion of the prothesis when fitted - indicates any high spots by leaving a coloured mark on it and on the opposing tooth
MILLER FORCEPS - used by some operators to hold the articulating paper in place. many operators place the articulating paper with their fingers only
VARIETY OF POLISHING BURS - to smooth over any areas of the prosthesis requiring reduction while the occlusion is corrected, so that a smooth, polished surface remains
PATIENT MIRROR - to allow patients to view the prothesis before fitting and ensure they are happy with the shade and allignment

Question 11

REMOVABLE PROSTHESIS - ITEMS FOR FIRST IMPRESSIONS:

Answer 11

STOCK IMPRESSION TRAYS - to be sized and used to take the initial impressions, so that the special trays can be constructed - they may be upper and/or lower, and edentulous or dentate (boxed)
ALGINATE IMPRESSION MATERIAL AND ROOM TEMPRETURE WATER - to be mixed in a mixing bowl with spatula, loaded into the trays and inserted to produce the initial impressions
SHADE AND MOULD GUIDES - to determine the colour and shape of the denture teeth, to be as close in appearance to any remaining teeth as possible - usually a diffrent shade guide to that used for fixed protheses
WORK TICKET OR DOCKET - to record the patient and dentist details, the denture design and base material to be used, the tooth shade and mould, the type and position of any clasps, and the return date

Question 12

REMOVABLE PROSTHESIS - ITEMS FOR SECOND IMPRESSIONS:

Answer 12

STUDY MODELS AND SPECIAL TRAYS - to make more accurate second impressions where required, in order to produce the working models
ALGINATE OR ELASTOMER IMPRESSION MATERIAL - to take the more accurate second impressions of the arch where the prosthesis is to be fitted
WORK TICKET - to record the next stage request and the return date

Question 13

REMOVABLE PROSTHESIS - WHAT ARE FIRST IMPRESSIONS FOR?

Answer 13

these are taken to produce the initial working model for the prosthesis construction and are sent to the laboratory for casting up

Question 14

REMOVABLE PROSTHESIS - WHAT ARE SECOND IMPRESSIONS FOR?

Answer 14

these are taken to provide more detail and better accuracy of the completed prosthesis, and many operators often incorporate this stage with that of the bite registration

Question 15

REMOVABLE PROSTHESIS - WHAT IS BITE REGISTRATION FOR?

Answer 15

this stage records the way that the patient normally bites, so that the prosthesis can be made to accurately fit into that bite, rather than to alter it. with edentulous patients, their occlusal face height has to be measured as a guide for the technician, as the patient has no actual bite to refer to.

Question 16

REMOVABLE PROSTHESIS - ITEMS FOR BITE REGISTRATION:

Answer 16

WAX BITE RIMS - adjusted in height so that the correct face height of the patient can be recorded
HEAT SOURCE - to warm the hand instruments and rims for adjustments
WAX KNIFE - to remove or add additional wax to the rims, as necessary
BITE REGISTRATION - to be mixed and applied to the rims, so that they are held in the correct position once set
PINK SHEET WAX - for addition to the rims, as necessary
WILLIS BITE GUAGE - to record the desired occlusal face height in edentulous patients, where no natural teeth remain as a guide
WORK TICKET - to record the next stage request and return date

Question 17

REMOVABLE PROSTHESIS - WHAT IS THE TRY-IN FOR?

Answer 17

this stage is a trial insertion of the removable prosthesis before it is sent to the technician for completion. the prosthesis may be a waxed base, with or without stainless steel clasp, or it may be a chrome-based design with the teeth held in wax. final adjustments can be made to the wax , the stainless steel clasps, the teeth and their shade at this point, and minimal adjustments to the chrome base

Question 18

REMOVABLE PROSTHESIS - ITEMS FOR TRY-IN:

Answer 18

TRY-IN PROSTHESES - to deterine if fit, occlusion and aesthetics are correct before finishing the dentures
HEAT SOURCE - to warm the wax and make adjustments, as necessary
Le Cron CARVER - to make fine adjustments to the wax area of the try-in as necessary
WAX KNIFE - to warm and smooth the wax after adjustments, as necessary
SHADE AND MOULD GUIDES - to check or alter the shade or mould, as necessary
PINK SHEET WAX - for addition to the try-in, as necessary
ADAM PLIERS - to adjust stainless steel or chrome clasps
PINK STONE WITH STRAIGHT HANDPIECE - to make minimal adjustments to the chrome base, as necessary. if the chrome base is inaccurate, it will need remaking at this point
PATIENT MIRROR - to allow patients to view the try-ins and decide if they are happy with the apperance before the completion of the dentures
WORK TICKET - to record any changes required for a retry or to record the fit return date

Question 19

REMOVABLE PROSTHESIS - ITEMS FOR FITTING:

Answer 19

COMPLETED REMOVABLE PROTHESES - to fit, to the patient and dentist’s satisfacation
STRAIGHT HANPIECE AND SELECTION OF TRIMMING BURS AND CARBORUNDUM POLISHING STONES - to remove any acyrlic pearls or occlusal high spots before polishing and smoothing the adjusted area for comfort
PATIENT MIRROR - to allow patients to view the completed prostheses
ARTICULATING PAPER OR OCCLUSAL INDICATOR WAX - to identify occlusal high spots, for adjustment as necessary
PRESSURE RELIEF PASTE - to identify high spots on the denture fitting surface, for removal as necessary

Question 20

THE EQUIPMENT AND ITEMS REQUIRED FOR REMOVABLE APPLIANCE FITTING AND ADJUSTING:

Answer 20

ADAM UNIVERSAL PLIERS - to adjust all metal springs and retractors, as necessary
STRAIGHT HANDPIECE AND ACRYLIC TRIMMING BUR - to adjust all acyrlic areas of the appliance, as necessary
MEASURING RULER - to record any measurable tooth movement, such as the overjet
EXPANSION SCREW KEY, WHERE NECESSARY - to count the number of turns applied to the screw between visits, to ensure compliance by the patient

Question 21

THE EQUIPMENT AND ITEMS REQUIRED FOR FIXED APPLIANCE BONDING AND ADJUSTING:

Answer 21

ARCHWIRE - felxible nickel titanium or stainless steel wires, to fasten into the brackets or bands
END CUTTERS - right-angled cutters to trim the ends of the archwire after replacement
ALASTIKS - rubber bands to hold the archwire into the slots of each bracket
ALASTIK HOLDERS - ratcheted holders to apply the alastiks to the brackets
BRACKETS - metal or ceramic components attach to each tooth, if they have been lost since the the previous appointment
BANDS - metal rings to attach to molars in particular, although bands are available for all teeth and were the only attachments available before brackets were developed
BRACKET HOLDERS - to hold and position each bracket to the centre of the tooth if any replacements are required
BRACKET AND BAND REMOVERS - to remove brackets, bands and any residual bond material before replacing, if necessary
BONDING MATERIALS - acid etch and orthodontic resin bond material - to hold the brackets onto the tooth
BAND CEMENT - any luting cement material, to hold bands onto the molar teeth

Question 22

THE EQUIPMENT AND ITEMS REQUIRED FOR RETAINER FIT:

Answer 22

BRACKET AND BAND REMOVERS - to remove the various components of the fixed appliance from the teeth, without damaging the teeth or causing pain to the patient
RETAINER - a passive removable appliance similar to the removable appliance, or a vacuum-formed “gum shield” design, or a passive wire bonded to the palatal or lingual aspect of the teeth when fixed appliances have been used
SCALE AND POLISH EQUIPMENT - to clean the teeth of any plaque or calculus debris once a fixed appliance has been removed
AIR TURBINE AND POLISHING BURS - to remove any residual bond material from the teeth after a fixed appliance has been debonded

Question 23

IMPRESSION MATERIALS USED FOR FIXED AND REMOVABLE PROSTHETIC PROCEDURES:

Answer 23

• ALGINATE
• ELASTOMER MATERIAL:
• silicone
• polyether and similar materials

Question 24

REASONS FOR PLACING TEMPORARY CEMENTS:

Answer 24

• to avoid sensitivity with the tooth/teeth
• to maintain the space around the prepared tooth/teeth for the fixed prosthesis to fit over accurately
• to maintain the occlusion between the prepared tooth/teeth and the opposing teeth, so that the fixed prothesis will fit accurately
• for aesthetics

Question 25

ZINC PHOSPHATE:

Answer 25

presented as zinc oxide powder and phosporic acid liquid, the cement is prepared by mixing increments of the white powder to the clear liquid on a glass slab with a spatula. setting of the cement takes a few minutes depending on various factors:

• a warm slab accelerates the setting time
• a cold slab slows down the setting time
• a thick mix sets more quickly than a thin mix
• a dry slab must be used, as moisture accelerates setting
• powder contaminated by moisture in the air will set too quickly for use, so that it is most important to screw the cap on tightly, immediately after using the bottle of liquid

Question 26

ZINC POLYCARBONATE:

Answer 26

this is presented as white zinc oxide powder and clear, viscous polyacrylic acid liquid or as these two components combined in the powder and sterile water as liquid. in each case, the cement is prepared by mixing increments of the powder with the liquid or sterile water on either a glass slab or a waxed paper pad, with a spatula. a measure is provided by the manafacturer for the exact measurement of each increment.

Question 27

GLASS IONOMERS:

Answer 27

these are composed of a powedered glass-like mixture of aluminosilicate particles and polyacrylic acid, which is measured accuratley with a scoop and then mixed with water.

Question 28

ORAL HYGIENE INSTRUCTIONS FOR FIXED PROSTHESES:

Answer 28

the general oral health messages to be relayed to patients following crown or bridge cementation are as follows:

• regular and thorough tooth brushing daily
• use of fluoride toothpaste and a medium textured toothbrush
• regular flossing to clean crown margins interproximally
• careful use of floss so as not to dislodge the crown
• attend for dental examinations so that margins can be checked professionally
• sensible diet, low in non-milk extrinsic sugars
• regular use of a good quality mouthwash to reinforce plaque control

Question 29

ORAL HYGIENE INSTRUCTIONS FOR REMOVABLE PROSTHESES:

Answer 29

Instructions are given on the wear, care and cleaning of the new dentures, as follows:

• a demonstration of how to insert and remove the dentures is given, with the patient then practising the techniques in front of the mirror and under the operators supervision
• avoid wearing them overnight if possible, to avoid the development of oral fungal infection (thrush)
• store them overnight in a denture pot containing water, or ideally a soaking agent such as steradent (for all-acrylic dentures) or dentural (for metal dentures)
• clean after each meal if possible, using a denture brush and denture toothpaste - some ordinary toothpastes may be too abrasive for use on the acrylic teeth
• clean over a bowl of water to avoid damage damage to the denture if it is dropped
• avoid soaking in bleach-based cleaners if any metal components are included in the design
• eat soft foods initially, while the oral soft tissues acclimatise to the prostheses
• take time to chew foods thoroughly to avoid causing indigestion by swallowing large food particles
• harden oral soft tissues by carrying out hot salt water mouthwashes initially, otherwise the new dentures are likely to rub the soft tissues and make them sore
• return to the surgery if any ulceration occurs beneath the dentures, as further adjustments are likely to be required to remove high spots and deep flange edges
• debate patients must continue to attend for oral health assessment at their regular recall interval, and edentulous patients are advised to attend at least once every 2 years, but ideally annually

Question 30

ORAL HYGIENE INSTRUCTIONS FOR FIXED ORTHODONTIC APPLIANCES:

Answer 30

• careful manual tooth brushing should be carried out after each meal
• good quality electric toothbrushes, may be safely used
• use of fluoridated toothpaste
• daily use of internal brushes to clean around each bracket individually
• avoidance of cariogenic and acidic food and drinks for the full period of treatment
• avoidance of sticky foods for the full period of treatment
• use of fluoride mouthwash daily to minimise the risk of decalcification
• regular use of of disclosing tablets to highlight problematic areas where plaque is being retained, in order to minimise the risk of decalcification

Question 31

ORAL HYGIENE INSTRUCTIONS FOR REMOVABLE ORTHODONTIC APPLIANCES

Answer 31

• wear as directed by the dentist
• clean the appliance and teeth after each meal using a toothbrush and toothpaste
• avoid cariogenic and acidic foods and drinks, as advised
• attend all dental appointments for the necessary adjustments
• contact the surgery immediately if there are any breakage or the the appliance is lost
• expect the appliance to feel tight initially after each adjustment
• contact the surgery if any prolonged or excessive symptoms occur
• If the appliance is to be removed for meals, ensure it is placed safety in a rigid container to avoid breakage during mealtimes