Dental Technology: Record Blocks and Articulators (Coursework Sample)

Dental Technology: Record Blocks and Articulators
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Introduction
This paper analyzes the process of making complete dentures and understanding articulators. Dentists are advised to answer specific questions when submitting a laboratory case to the dental laboratory. Before fabricating dentures, the physician ensures that the tissues are in a healthy state with no pathologic or inflammatory changes. Some of the diagnosis that are performed include reviewing the medical and dental history of the patient, physical as well as radiographic examination (Basker et al., 2011).
Response to Task 1
In this case, the intraoral examination is completed while recording the observations on the forms provided. The doctors are advised to pay attention to the reasons their patients have opted for that particular care. Subsequently, the current and appropriate radiographs are observed and the necessary readings recorded. The importance of reviewing medical history lies on the need to address deviations from the expected treatment outcome. In situations where the patient exhibits adverse tissue sensitivity to the current dentures, the physicians ought to provide the appropriate therapy (Grant and McCord, 2000).
Some of the baseplate material requirements include the ease to form, reproduce model detail, compatibility with wax or other block materials, inability to disintegrate at mouth temperature and whether it can be adjusted easily at the chair when necessary. Blocks are prepared after meeting the above criteria in which the physician prepares preliminary alginate impressions in full denture trays. The preliminary casts are designed to contain relief areas, tray extensions, and wax spacer areas. Tray extensions are outlined 2-3 millimeters short of the targeted denture end whereby the line ought to cross the plate distal to the targeted denture end.
The outline of the maxillary palatal and ridge crest stops are marked followed by blocking out undercuts and positioning wax spacers. Tinfoil substitute is applied to cast and wax, mixing acrylic resin tray material and adapting it to the cast. Mental or resin handles are constructed and contour borders followed by removing sharp areas and disinfecting trays. The wax spacers should not be removed yet at this moment. In partial record blocks, the wax block is left at the same height and width as the standing teeth. Undercuts are blocked out; the models are soaked if dry and a sheet of wax adapted. Excess wax is trimmed off without covering the occlusal surface of the standing teeth, and a wire strengthener adapted as well as wax into the edentulous spaces (Johnson et al., 2011).
Subsequently, frenum is relieved followed by smoothing and shining. The maxillary impression ought to fill the vestibule as well as the buccal spaces whereby it goes behind the tuberosity and the hamular notch in continuity with the post palatal seal. With this, no anterior-posterior rocking or shifting should exist since a movement in the impression during setup would lead to formation of airspaces underneath when processed. Most of the movements in the lower denture are caused by combinations of constricted retromolar pad area, an overextension as well as the inadequate anterior floor of the mouth.
Regarding Johnson and Wood (2012), it is important to follow the criteria keenly to avoid cases of the denture continually lifting rather than having a seal. Retromolar pads are used as landmarks for extensions on the retro mylohyoid regions and the buccal shelf. The denture base, on the other hand, should fill the anterior floor mouth space between the alveolus and the sublingual fold. Grant and McCord (2000) state that these guides through which teeth can be arranged with the incisive plane are an important tool for the arrangement of anterior teeth.
The design criteria are standardized since patients have varying values for the distance between anterior teeth and the incisive plane. Using the standard criteria involves accurate points of measurement thus assisting us to decide on the correct value to be deployed in restoring the labial nasal to 90 degrees. Preserving the natural appearance is an important element of treatment whereby the criteria defined proves useful in finding the suitable position. A pleasing lip support can be achieved by placing the anterior appropriately with their matrix and burden placed on the central incisors.
Response to Task 2
The information sent out to the dental technician includes the name of the patient, date of birth, the length of anterior teeth, lip length and the current central incisors’ position. Besides, the width of the nasal wings, appropriate tooth characteristics and skeletal jaw situation amongst others are provided. The jaw relations are recorded to facilitate the production of complete dentures. Incorporation of errors in these records results in uncomfortable dentures that cause harm to elements making up the stomatognathic system. The intermaxillary relations are three dimensional and to simplify the process, only three elements are recorded (Johnson and Wood, 2012).
To begin with, the vertical plane is considered to analyze the degree of jaw separation. The other element relates to the horizontal plane that is concerned with anteroposterior relations. The third element relates to the coronal plane in cases where lateral relations of the jaw are kept in consideration. The retruded contact position is the recommended site to record the mandibular anteroposterior position. Markings made by dentists on the bite registration block includes midline, canine line, and smile line. Canine lines determine the upper anterior width in which canines are positioned. The smile line is included to give an impression of the length of the upper anterior (Johnson et al., 2011).
Response to Task 3
Regarding Heath et al. (1987), articulators enhance clinical dental practice and are vital in the production of complete dentures. They are mechanical instruments to hold lower and upper models of the mandible and maxilla in a similar manner as they exist in the mouth. Articulators generate similar movements of the mandible during functioning. They range from the plane line, an average value or fixed condylar path, semi-adjustable anatomical, and fully adjustable anatomical. The design features include arms for attaching the models with or without plaster. The two arms are then interlocked at a movable joint that is a mechanical representation of the tubular mandibular joint.
Macgregor (1989) states that plane line articulators are simple to use and can only make open and close movements. Average value or fixed condylar path articulators incorporate the basic movements made by the TMJ. The condylar angle set for most patients is between 25-30 degrees. Semi-adjustable articulators are used together with a face bow thus adjusting it to record the mandibular movements made by patients. This is extremely important in facilitating the placement of the maxilla in the correct relation to the condyles. Fully adjustable articulators allow dentists to adjust the distance between condyles. Arcon designed articulators are built on the upper element of the articulator whereas the condyles are fixed on the lower element of the articulator. For non-arcon articulators, they are designed in a way that the condylar housing exists in the lower component. The condyles are placed on the upper component with the design representing an inversion of the anatomy of the human skull.
Response to task four
Following the completion of maxillomandibular records and preparing the face-bow transfer, the materials and instructions are sent to the technicians. When mounting the casts, the articulator is checked and adjusted accordingly. The condylar elements are locked in a centric position whereby no lateral play is allowed in the articulator. The mountings rings are attached firmly, and the casts are placed in their respective occlusion rims. The inability to observe these precautions results in casts that are mounted against the suitable relationship. The cast support behind the maxillary cast is noted and attached to the lower mounting ring of the articulator to boost the maxillary occlusion rim in the mounting procedures (Basker, Davenport and Thomason, 2011).
The face-bow is mounted and centered appropriately on the articulator. Subsequently, the face-bow has condylar roils that are adjusted in a manner that they lit snugly on the articulator’s condylar roil without distorting the face-bow. The mounting support is placed on the articulator and the jack screw holding the bite fork is lowered to achieve the same level of the orbital plane. The articulator is then opened for applying the plaster to the maxillary cast’s base. A moderate mix of impression plaster is prepared and placed on the cast’s base and piled up to exceed the mounting plate’s level. Once the models are poured, trimmed, the technician obtains the face-bow and centric record and mounts the models. Regarding Johnson and Wood (2012), the maxillary model is mounted first using the face-bow followed by the mandibular model through the centric relation record. To create the proper mounting, the models are verified to fit the face-bow as well as the centric relations records without any imperfections. In this case, I will provide images of a putty model articulated on a plasterless articulator.



Figure  SEQ Figure \* ARABIC 1: The plaster-less articulator.




Figure  SEQ Figure \* ARABIC 2: Fabricated putty model
A putty model is being fabricated to articulate on a plasterless articulator. With a full upper (F/-) record block with an acrylic base plate and the dentate lower working model. The operator at this point seats the mandibular cast, seals it on the record base appropriately and the land area is reduced i...