Dental Wax - A Comprehensive Guide PDF

Dental wax Marketing Department Mon. Feb. 21. 2018 Dental wax Dental wax Dental wax Dental wax  Dental waxes are thermoplastic materials which are normally solids at room temperature but melt, without decomposition, to form mobile liquids. They are essenti...

Dental wax Marketing Department Mon. Feb. 21. 2018 Dental wax Dental wax Dental wax Dental wax  Dental waxes are thermoplastic materials which are normally solids at room temperature but melt, without decomposition, to form mobile liquids. They are essentially soft substances with poor mechanical properties and their primary use in dentistry is to form patterns of appliances prior to casting. Dental wax Natural waxes are produced from: Plants :carnauba wax Insects :bees wax Minerals :paraffin wax Natural waxes are combined or mixed with synthetic waxes, gums, fats, oils, resins and coloring agents to form dental waxes. Dental wax Classification of dental waxes Processing Pattern Impression Boxing & Inlay Corrective Beading casting Bite Sticky RPD casting registration Utility Base plate Carding Shellac Dental wax Dental wax Physical properties 1. Melting Range Dental waxes have melting range rather than melting point because they are mixture of more than one type of wax and other additives; each has its own melting point. Melting range is a range of temperatures at which each component of the wax will start to soften and then flow. 2. Flow Flow is dependent on temperature (flow of wax is greatly increased as the melting range is approached). For the direct inlay wax, the material must have a relatively high flow a few degrees above mouth temperature (workable but comfortable). Dental wax At mouth temperature, no flow is required to minimize the possibility of distortion of the pattern during removal from the tooth Insufficient flow lead to lack of details and increased internal stresses. Dental wax 3. Residual stresses Waxes have low thermal conductivity making it difficult to achieve uniform heating. Adaptation of wax to a certain shape with non homogenous softening will result in stress set up in the material and relief of stresses lead to distortion of the wax pattern. Dental wax 4. Dimensional Change The coefficient of thermal expansion and contraction of dental waxes is greater than any other dental material. Waxes expand when heated and contract when cooled. Temperature changes due to great coefficient of thermal expansion and contraction of the pattern wax may be a major contributing factor in the inaccuracy of the finished restoration Dental wax 5. Mechanical properties Elastic modulus, proportional limit and compressive strength of dental waxes are lower than any other dental materials. These properties depend on temperature. 6. Ductility Ductility of waxes increases as the temperature increases. Waxes with low melting point have greater ductility. Ductility of mixed waxes with wide melting range is greater than those of narrow melting range Dental wax I. Pattern waxes Pattern waxes are used in the construction of metal castings and bases for dentures. 1. Inlay waxes These waxes are supplied in blue or green form. Used to prepare wax patterns of inlays, crowns, & bridges Dental wax Dental wax Desirable Properties 1. Not sticky to touch. 2. Low thermal expansion. 3. Completely burnt out without leaving any residue. 4. Appropriate melting ranges. 5. Soften without flaking. 6. Adequate flow to record the cavity details. Dental wax Type I : medium wax, used in direct technique It is used directly in the mouth where it is softened and placed into the prepared tooth in the direct waxing technique. It has a lower melting range for the comfort of the patient and the accuracy of the wax on removal. Has a softening point slightly higher than the mouth temperature. Dental wax Type II : soft wax, used in indirect technique It is more frequently used, where wax is melted onto a die outside the mouth. Most dentists prefer to use this and have a dental laboratory technician to produce the wax pattern and casting. Dental wax Manipulation inlay pattern wax 1. Direct technique Wax should be passed over flame & then remove. Process repeated until wax is uniform throughout. Kneaded together & shaped to prepared cavity. Pressure applied. Carefully removed Dental wax 2. Indirect technique 1. Die lubricated 2. Melted wax is added in layers. 3. Cavity is overfilled & carved 4. Final finishing with fine cloth toward the margins. Dental wax Wax Distortion Causes: 1. Non-uniform heating of the wax when inserted in the cavity. 2. If wax is not held under uniform pressure during cooling. 3. During carving. Dental wax To avoid: ▪ Minimal carving & change in temperature. ▪ Invest immediately. ▪ Use warm instruments for carving. ▪ Store in fridge if necessary. 2. Casting Wax CASTING PROCEDURE 28 Dental wax They come in the form of sheets and preformed shapes, used to construct the metal framework of partial and complete dentures. Physical properties 1. They have little flow at mouth temperature and high degree of flow at higher temperature since they are used in laboratory procedures. 2. Slight degree of tackiness to maintain their position on the cast during the assembly of the pattern. Dental wax 3. Base plate wax Dental wax They are sheets of wax generally pink in color to simulate the color of the gingival. Physical properties 1. The wax must not distort at mouth temperatures. 2. If heated or washed up with hot water, no residue remains. 3. Easy to mould without flaking or tearing. 1. These sheets are layered to produce the form on which denture teeth are set. 2. Occlusal bite registration. 3. Spacer in custom trays. 4. Waxing up (producing the desired contour) of the trial denture after setting of teeth Dental wax Dental wax Dental wax II. Processing waxes These waxes are used primarily to aid in dental procedures both clinically and in laboratory. 1. Boxing wax It is supplied in the form of green or black sheets with smooth glossy surface. Dental wax Dental wax Physical properties It is easily manipulated. Slightly tacky at room temperature, allowing it to adhered to itself to secure the boxed form. Retain its shape with minimum flow. Use It is used to form a gypsum model with its base in one step. Technique The 1.5 inch wide, red strip of boxing wax is wrapped around the impression to produce a form into which the gypsum is poured. Dental wax 2. Utility wax It is also called periphery wax. It comes in orange or dark red ropes and sheets. Physical properties 1. Adaptable and workable at room temp. 2. Adhesive and tacky at room temperature. Dental wax USES To adapt the periphery of the impression and aid in patient comfort. Dental wax 3. Sticky wax It comes in yellow or orange sticks. Uses 1. Used for alignment of fractured pieces of dentures or casts temporarily during repair. 2. Used to fix the soldered components (e.g. bridge parts during their soldering together Dental wax Dental wax Physical properties 1. It is hard and brittle at room temperature, but when heated under flame, it becomes soft and sticky. 2. Free from tackiness at room temperature Dental wax 4- Dental wax Dental wax 5- Carding wax Dental wax III. Impression waxes It is used to obtain impressions of the oral structures so they exhibit high flow 100% at mouth temperature. Dental wax 1. Corrective impression wax It is used as a wax veneer over the original impression materials in the process of taking edentulous impressions. This wax flows at mouth temperature and is used within another (original) impression material to record soft tissue fine details in a functional state. They are replaced by elastomeric impression materials. Dental wax Dental wax 2. Bite registration wax It is supplied in the form of preformed horseshoe shapes. It is used to produce wax bite registrations for articulation of models. It is susceptible to distortion at temperature slightly higher than mouth temperature. Dental wax Dental wax Thank You