Flashcards
Introductory Techniques
Cards in this deck (24)
- 1Define: Labial and BuccalLabial - Front surface of anterior teeth, closer to the lips
Buccal - Front surface of posterior teeth, closer to the cheeks - 2Define: Lingual and PalatalLingual- Surface closest to the tongue in the mandible
Palatal - Surface closest to the palate in the maxilla - 3Define: Mesial and DistalMesial - Surface nearest to the midline of the body
Distal - Surface furthest from the midline of the body - 4Define: Incisal and OcclusalIncisal - The cutting edge or the anterior teeth
Occlusal - The biting and grinding surface of the posterior teeth - 5Draw and label the anatomical landmarks that may be present on an edentulous maxilla...
- 6Draw and label the anatomical landmarks that may be present on an edentulous mandible...
- 7Describe the FDI tooth notation systemThe FDI identifies teeth using two digits. The first digit indicates the quadrant, the second digit indicates the tooth number from 1-8.
Deciduous teeth quadrant 5-8, tooth number from 1-5 - 8Define: A dental impressionA dental impression is a negative likeness of the hard and soft tissues in the patients oral cavity in which a reproduction of the positive can be created.
- 9What are the criteria of a useful impression tray?- The surface covers the entire prosthesis/restoration bearing area.
- It supports the impression material during and after setting.
- It guides the material to the mucosa.
- Be rigid and dimensionally stable.
- Be evenly spaced from tissues so dimensionally changes in the impression material are equal.
- It does not harm the patient. - 10What are the two types of dental impression trays?Stock trays - Mass produced and are available in generic shapes and sizes. Made from plastic or stainless steel.
Special tray - Made by dental technician specifically for an individual patient. Made from light cure material, acrylic and shellac. - 11What are primary casts used to analyse?- The feasibility of dental treatment.
- The relationship between the mandible and maxilla.
- Tooth relationships.
- Specific areas in the oral cavity.
-Possible forms of treatment. - 12Identify 5 different special tray design and construction considerationsSpecial tray handle design - Dentate - protrudes from the oral cavity at 10 degree angle from incisal edge of teeth. Edentulous - orientated at 45 degrees from the crest of alveolar ridge.
Special tray extension - 2mm above labial lingual and buccal sulci. follow vibrating line and cover retromolar pads.
Fitting - Close fitting trays are used with more rigid impression materials that require very little thickness to maintian their dimensional stability. Spaced special trays are used with more elastic impression materials that require thickness to maintain their dimensional stability.
Mucostatic/Mucocompressive
Finger rests - even pressure along the body of the special tray
Stops- ensure uniform thickness of impression material. - 13Describe: Mucostatic and mucocompressiveMucostatic impression trays take an impression of the soft tissues in their normal resting position. This is because there are perforations in the tray that allow the impression material to escape, relieving pressure and not distorting the tissues. These are generally used for dentate patients and require a spaced tray so that the impression material has enough thickness to maintain its dimensional stability.
Mucocompessive impression trays subject the tissues to compression during the impression taking process. This is because there are no perforations for the material to ecscape, building pressure and causes the tissues to deform. These are generally used for edentulous patients and are close fitting because there are less undercuts present. Usually a Zoe impression paste is used because it requires less thickness to maintain it's dimensional stability. - 14What are the common mixing ratios for plastersDental SP - White plaster - 100:60
Dentstone KD - Yellow plaster - 100:30
Crystacal R - White plaster - 100:25 - 15What are the two techniques for casting impressions?Single stage - cast and base are created with one mix of plaster.
Two stage - cast and base are created with two different types of plaster. - 16Advantages of boxing and beadingPreserves peripheral roll
It provides and defines a protective edge around the cast
Can produce an accurate cast to specific dimensions
Minimises model trimming - 17What is an occlusal rim?An occlusal rim is a wax extension of a base plate that is used to establish tooth and jaw relationships in the construction of a complete or partial denture.
- 18What information is recorded on occlusal rims?Centric relation
High lip line
Occlusal plane
Width of teeth
Lip contour
Centre line
Vertical dimension
Canine lines - 19Advantages of solid base plateAdvantages:
• They give a 'true picture' of how an acrylic denture will seat in the mouth.
• They are naturally mucodisplasive.
• The base plate will not distort when inserted into the mouth.
• The dentist can use the plate to take a wash impression if required (but only solid baseplates that cover the entire denture bearing area). - 20Disadvantages of solid base platesDisadvantages:
• They take longer to construct (especially in heat cure).
• They are comparatively more difficult to manufacture than a wax baseplate.
• Monomer is used during construction.
• They are more difficult to adjust than wax (especially in designs where the baseplate covers the entire denture bearing area). - 21What are the causes of denture fractures ?1). INTRAORAL CAUSES.
These are changes in the oral cavity that have an adverse effect on the denture. Alveolar bone changes (such as bone resorption) may cause the denture, to become poorly seated or rock on a bony prominence. This rocking action produces stress in the denture base eventually resulting in a fracture.
2). INCORRECT CONSTRUCTION.
These are where the dental technician or dentist has made an error during the denture construction process that eventually results in a fracture. Construction errors could include the incorrect positioning of teeth, inadequate polymerization and thin acrylic baseplates
3). ACCIDENTAL HANDLING.
This is where the patient accidentally damages the denture such as dropping it during cleaning. Accidental handling could also include trauma, such as a blow to the face. - 22What is a thermoplastic splint?The thermoplastics used in dentistry are synthetic polymers, usually some variation of polypropylene or polyvinylchloride (PVC). They are supplied to the dental laboratory as a circular or square plastic sheet, the thickness of which can vary from around 0.5mm to 5mm depending on its intended purpose.
- 23Describe thermoplastic splint using a vacuum machine.below shows a diagrammatic representation of a vacuum forming machine. The red box represents a plaster model and the yellow line represents the thermoforming "blank". The blank is heated under a heating element until soft and pliable. Once the blank has reached the desired temperature the heating element is removed and the blank is quickly dropped onto the model. The carrier and blank create a seal and the blank is sucked down over the model using a vacuum pump.
- 24What are the uses for a thermoplastic splint?Orthodontic retainers are a hard, thin plastic splint designed to prevent teeth from drifting back to their original positions after orthodontic treatment.
Orthodontic tooth aligners.
Similar in form to common orthodontic retainers, aligners are used to make small adjustments to tooth positions. This is done by carefully sawing out the teeth on a plaster model and fixing them in a new position.
Bruxism splints.
Bruxism is the medical term for grinding the teeth and clenching the jaw that results in jaw pain, discomfort and wearing of the occlusal surfaces.. A bruxism splint is a soft thermoformed blank pulled completely over the teeth. The splints create even pressure across the jaw and a physical barrier between your upper and lower teeth.
Sports mouth guards. A custom made mouth guards may come in different thicknesses and designs depending on its intended purpose.
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- Flashcards on Introductory Techniques, created by Abigail Withers on 03/12/2017.
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- Abigail Withers · Dec 2017
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- Feb 12, 2020
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