1 Table of contents Chapter I: Introduction to Complete Denture .........................2 Chapter II: Anatomical Landmarks ........................................... 6 Chapter III: Impression Trays and techniques ............................. 28 Chapter IV: Relief Areas......................................................43 Chapter V: Record Base and occlusion rim ............................. 55 Chapter VI: Face Bow.................... ................................... 68 Chapter VII: Articulators................................................... 70 Chapter VIII: SELECTION, of artificial teeth and WAXING-up 92 Chapter VIII: Processing Dentures .......................................110 2 Chapter 1 Introduction to complete denture Prosthetics: It is the art and science of designing, supplying and fitting artificial replacement for missing part of the human body. Prosthesis: Is the artificial appliance which replaces a lost part of the human body. Prosthodontics or Prosthetic Dentistry : It is a branch of dental science which deals with replacement of missing teeth and associated structures by using artificial devices to restore function and esthetics. Prosthodontics 1- Fixed prosthodontics. 2- Removable prosthodontics: a- complete denture b- partial denture 3- Maxillofacial prosthodontics. Removable Prosthodontics is the art and science of replacement of missing teeth and oral tissues with a prosthesis designed to be removed by the wearer. It includes removable complete and removable partial prosthodontics. Dentulous: A condition in which natural teeth are present in the mouth. Edentulous: A condition in which all natural teeth are lost. Partially Edentulous: A condition in which some of the natural teeth are lost. Retention : is a quality inherent in a prosthesis acting to resist dislodging forces along the path of placement. Stability is the quality of prosthesis to be firm, steady, or constant, to resist displacement by functional horizontal or rotational forces. 3 Support is the quality of prosthesis to resist vertical tissue ward force. Supporting area is the foundation area on which a dental prosthesis rests. Complete Denture Prosthodontics: Complete denture prosthodontics involves the replacement of the lost natural dentition and associated structure of the maxilla and mandible for patients who have lost all their natural teeth. Objectives of Complete Denture Prosthodontics 1- Restoration of the masticatory function. 2- Restoration of the normal appearance. 3- Correction of speech defects resulting from loss of natural teeth. 4- Preservation of the alveolar bone and tempromandibular joints. 5- Satisfaction and comfort of the patient. Denture surfaces Complete denture consists of denture base that rest on the supporting structure and to which an artificial teeth attached to it. It has three surfaces: 1-Fitting surface: (intaglio surfaces, impression surface) determined by the impression. 2-Polished surface: includes the facial (labial and buccal), lingual and palatal surfaces. 3-Occlusal surface: that makes contact with the opposing denture. Denture borders: The margin of the denture base at the junction of the polished and impression surface. 4 Denture flanges The vertical extension of the denture base that extends from the cervix of the teeth to the borders of the denture flanges; they are named according to location into: Labial flange: the portion of flange that occupies the labial vestibule. Buccal flange: the portion of flange that occupies the buccal vestibule. Lingual flange: the portion of mandibular denture flange that occupies the alveololingual sulcus. The differences between natural teeth and artificial teeth Natural Teeth Artificial Teeth Type of support The teeth are supported by periodontal tissue which gives support, positional adjustment of teeth and proprioceptive response. All teeth are on bases and supported by mucosa which is not created to be covered. Area of support in both jaws About 90 cm square. About 35 cm square of edentulous mouth. Amount of masticatory forces From 5 - 17.5 pounds. About 10 - 15% of its value in natural dentition. Effect of masticatory forces The masticatory forces are transmitted to the bone in the form of tension through the periodontal The force is not directed to the entire alveolar bone but is applied only on its surface in the form o f compression. This compression has limited 5 ligament. This tension is well accepted by the alveolar bone and may even service as stimulus for alveolar bone remolding tolerance by the bone and may cause alveolar bone resorption. Effect of pressure on teeth Each tooth receives individual pressure and moves independently. Teeth move as a unit on a base. Effect of non - vertical components of forces Well tolerated. Cause trauma to the supporting tissue and reduce stability to the denture. Incising forces Not affect posterior teeth. Cause tipping of the denture base especially if the teeth are not balanced articulated. Proprioceptive response The proprioceptive mechanism act as a useful alarm protecting both the supporting structures of the tooth and the substance of the crown from the effects of excessively vigorous masticatory movements. By the loss of natural teeth there is no proprioceptive mechanism. 6 Steps of Complete Denture Construction: Clinical Steps Laboratory Steps 1 - History taking and examination of the mouth. - Preparing the mouth for dentures. 2 - Taking of preliminary impressions (in stock trays) 5 - Taking of final impressions (in special trays) and determining of the posterior Palatal seal. 8 - Recording of jaws relations, face bow transfer and selection of teeth. 11 - Trying in the waxed denture. 15 - Registration of new centric relation andface bow transfer for clinical remount (If needed). 17 - Delivery of the finished denture and instruction for their use. 18 - Review of the denture (inspection and aftercare). 3 - Casting of the preliminary impression (using plaster of Paris). 4 - Construction of special trays. 6 - Boxing in and casting of the final impression (using dental stone). 7 - Construction of occlusion record blocks. 9 - Mounting of the casts with the record blocks on the articulator. 10 - Setting - up of the teeth and waxing - up. 12 - Processing o f the denture (Flasking, wax elimination, packing, curing and deflasking). 13 - Laboratory remounting of the denture and correction of occlusion by selective grinding. 14 - Finishing and polishing. 16 - Remount of the denture on articulator for adjustment of occ lusion (if needed). 7 Factors Influencing the Outcome of Prosthetic Treatment The successful outcome of prosthetic treatment depends upon (1) The dentist – who makes a diagnosis, prepares a treatment plan and undertakes the clinical work. (2) The dental technician – who constructs the various items which terminate in the finished dentures. (3) The patient – who is faced with coming to terms with the loss of all the natural teeth and then of having to adapt to the dentures and accept their limitations. 8 Chapter 2 Anatomical Landmarks of Prosthetic Interest These are anatomical guides that help in denture construction. These landmarks are either bony landmarks or soft tissue landmarks. [ I ] Extra-oral Landmarks Of Prosthetic Importance 1- Inter-pupillary line Description - Imaginary line running between the two pupils of the eye when the patient is looking straight forward. Significance helps in establishing the anterior occlusal plane of the artificial teeth of the denture. 2- Ala-tragus line (Camper's line) Description - Imaginary line running from the Inferior border of the ala of the nose to the superior border of the tragus of the ear. Significance Help in establishing the posterior occlusal plane of the artificial teeth of the denture. 3- Canthus-tragus line Description - Imaginary line running from the outer canthus of the eye to the superior border of the tragus of the ear. Significance - Help in locating the position of the condyles. 9 4- Naso-labial sulcus Description - Depression that extends from the ala of the nose in a downward and lateral direction to the corner of the mouth. Significance The sulcus becomes more prominent with aging and due to loss of teeth and vertical dimension. It can be modified by proper degree of jaw separation and tooth positioning. Plumper’s (thick denture flanges) improve the condition but it may interfere with muscular activity. 5- Vermillion border Description - The transitional epithelium between the mucous membrane of the lip and the skin. The amount of vermillion border shown on the lips depends on 1-The bulk of the orbicularis oris muscle. 2- The amount of the labial alveolar bone. 3-The alignment of the anterior teeth. Significance After loss of teeth, the amount of vermillion border shown on the upper lip is reduced. The condition can be corrected by thickening of the labial flange of the denture and proper positioning of the anterior teeth. 6- Mento-labial sulcus Description - Depression runs horizontally between the lower lip and chin. Significance Its curvature indicates the character of the maxillomandibular relationship and the degree of over-closure. Angle Class 1 normal ridge relationship: The sulcus shows a gentle curvature with obtuse angle Angle class II (retruded mandibular relation): The sulcus forms an acute angle 10 Angle class III (protruded mandibular relationship): sulcus forms an angle of almost 180 7- Philtrum Description - It is a diamond shaped depression at the center of the upper lip and base of the nose. Significance After loss of teeth, the philtrum becomes flattened. This condition can be improved by construction of proper denture with an appropriate arch-form and tooth alignment. 8- Modiolus Description - The point of meeting of buccinator and other facial muscles distal to the angle of the mouth. The modiolus is held in position by the arch-form of the maxillary teeth. Significance With the loss of teeth the modiolus drops. The appearance can be improved by proper positioning of the maxillary teeth. Narrowing of the lower denture base related to the modiolus is usually necessary to avoid displacement 9- Angle of the mouth (commissure of the lips) Description - Point of meeting between the upper and lower lip. Significance - (Angular Chilitis): Inflammation and ulceration as a result of: 1- Prolonged edentulism. 2- ↓ vertical dimension of complete denture. 3- Vitamin B deficiency. 11 10- The Angle of the Mouth and the Outer Canthus of the Eye Significance The distance from the outer canthus of the eye to the angle of the mouth was used by Wills to determine the vertical dimension of the edentulous patient at rest by making the distance from the base of the nose to the lower edge of mandible equal to it. [II] Intra-oral landmark of prosthetic importance The denture foundation can be divided into: -Supporting structures. -Peripheral limiting or sealing areas Anatomic Landmarks of the Denture Bearing Area (supporting structures): In the Maxilla 1-The residual ridge and hard palate 2- The incisive papilla 3- The palatine rugae 4-Median palatine raphe 5- Maxillary tuberosity 6- Torus palatinus 7- Fovea palatinae 8- Incisive fossae 9- Canine eminence 10- Buttress of the zygomatic bone In the Mandible 1- Residual alveolar ridge 2- Retromolar pad 3- Internal oblique ridge (mylohyoid ridge). 12 4- External oblique ridge 5- Buccal shelf of bone 6- Mental foramen 7- Genial tubercles 8- Torus mandibularis Anatomic Landmarks that Limit the Periphery of the Denture (limiting structures): In Relation to Maxillary Denture 1- Labial frenum 2- Labial vestibule 3- Buccal frenum 4- Buccal vestibule 5- Pterygo maxillary notch (Hammular notch) 6- Vibrating line. In Relation to Mandibular Denture 1- Labial frenum 2- Labial vestibule 3- Buccal frenum 4- Buccal vestibule 5-Masseter muscle influencing area 6-Retromolar pad and inferior border of the ramus 7- Pterygomandibular raphe 8- Plato glossal arch 9- Lingual pouch 10-Mylohyoid muscle influencing area 13 11- Lingual frenum ANATOMIC LANDMARKS OF THE MAXILLA A] The Denture Bearing Area (Supporting Structures) Landmark Description Significance 1 - Residual ridge - The portion of the alveolar process& it's soft tissue covering that remains after extraction. - It covered by a dense connective tissue fibers so, it act as a 1ry stress bearing area. 2 - vault of the palate The vault of the palate has different forms according to the pattern of development of the maxillary processes. The palatal arch may be V shaped, U - shaped or flat. The moderately high U - shaped vault is the more common and is more desirable for denture stability. 3 - Incisive papilla - Pear - shaped elevation present in the midline behind the 2 centrals. - After extraction of teeth it migrates to the crest of the ridge. - It should be relieved to avoid the burning sensation of the palate. 4 - Palatine rugae area - It is irregular elevations - 2ry stress bearing area. 14 radiates from the midline of the anterior part of the palate. - Prevent forward movement of the denture. - If it is sensitive or prominent it should be relived. 5 - Median palatine raphe - The mucoperiosteum that covers the median palatine suture. - When it is prominent it should be relieved. - Lack of relief cause: 1 - rocking of the denture due to bone resorption. 2 - Tissue ulceration. 3 - Mid - line denture fracture 6 - Maxillary tuberosity - Bony prominence located posterior to the upper 3 rd molar. - Aid in support, retention and stability of the complete denture. - When it is large: 1 - Relieved 2 - Modify the path of insertion.(unilateral enlargement). 3 - Surgical removal. 7 - Torus palatinus - Bony prominence - present in 20% of the 15 present at both sides of the midline of the palate. population. - It should be: 1 - Relieved. 2 - Surgical removal. 8 - Fovea palatinae - Two openings of minor salivary glands present in both sides of the midline posterior to junction of hard and soft palate. - It determines the posterior extension of the upper complete denture to be 2mm posterior to it. 9 - Incisive fossa It is a slight depression in the labial surface of the maxilla opposite the region previously occupied by the root of upper lateral incisor. 10 - Canine eminence It is found in the labial surface of the maxilla. It is a rounded bulge at the corner of the mouth opposite the region previously occupied by the root of the maxillary canine. 10 - Buttress (root) of the It is formed by the lower This area provides 16 zygomatic bone portion of the zygomatic process of the maxilla which flares upward and outward from the area above the first molar excellent resistance to vertical forces as It’s almost at right angles to the occlusal forces. - avoid vertical overextension in the first molar region, as mucosal injury may result from a sandwiching of the s oft tissues between the denture border and the zygomatic process of the maxilla. With resorption the denture may require relief over it 17 B] Border structures that limit the periphery of maxillary denture Landmark Description Significance Maxillary labial frenum It is a fibrous band covered by mucous membrane that extends from the labial aspect of the residual alveolar ridge to the lip. It may be single or multiple and may be narrow or broad. It contains no muscle so it can be surgically ex iseced if it attach near the crest of the ridge. A labial notch must be provided in the midline of the denture border opposite to the frenum. This notch prevents ulceration of the frenum or displacement of the denture. Labial vestibule The labial vestibule extends in both sides between the labial frenum and the buccal frenum. The labial flange of the maxillary denture occupies the space bounded by the residual alveolar ridge, and the lip. The major muscle in this area is orbicularis oris. Buccal frenum It is a fold or folds of mucous membrane extend from the buccal mucous It requires more clearance in the denture flange for its action. In adequate 18 membrane reflection towards the slope or crest of the residual ridge. They vary in size, number and position. provision for the buccal frenum or excess thickness of the flange distal to the buccal notch can cause dislodgment of the denture. Buccal vestibule It extends from the buccal frenum to the hamular notch. It houses the buccal flange of the denture between the ridge and the cheek. The thickness of the distal end of the buccal flange of the demure must be adjusted to accommodate the coronoid process of the mandible; otherwise it will push the denture out of place Pterygomaxillary (hamular) no tch It is a depression lies between the pterygoid hamulous posteriorly and the maxillary tuberosity anteriorly It is a displaceable area about 2mm wide It is used as a boundary of the posterior border of the maxillary denture. The tissue in this notch is easily compressed and the post dam line of the upper denture should be carried into this region to ensure an adequate peripheral seal. Bases short of the hamular notch will end on 19 the thin - nonflexible – tissue of the tuberosity and will consequently lack retention. Vibrating line of the palate The vibrating line is an imaginary line drawn across the posterior part of the palate that marks the beginning of motion in the soft palate when the patient says "ah.“ It extends from one hamular notch to the other. This line is not well defined and is better described as an area rather than a line. The maxillary denture posterior end should extend to this line. ANATOMIC LANDMARKS OF THE MANDIBLE A] The Denture Bearing Area (Supporting Structures) Landmark Description Significance 1- residual ridge - The portion of the alveolar process& it's soft tissue covering that remains after extraction. - Don't used as 1ry stress bearing area → Covered by movable fibrous connective tissue. - Don't Provide stability or support. 20 2 - External oblique ridge - Bony ridge running downward and forward from ramus to reach mental foramen. In the impression, the external oblique ridge shows a groove. The impression should record the ridge 3 - Buccal shelf area - Bony area ex tends between the external oblique ridge and the residual ridge. The buccal shelf area can range from 4 - 6 mm wide on an average mandible to 2 - 3mm or less in narrow mandible. - Used as 1ry stress bearing area: 1 - Perpendicular to the vertical masticatory force. 2 - Formed from compact bone. 3 - Provide support. 4 - Mental foramen - It's located on the Buccal surface of the mandible between the roots of 1st and 2nd premolar. - Lack of relief → numbness of the lower lip. 5 - Retromolar pad - Pear - shaped area located distal to the lower 3rd molar. It consists of mucous - Shock absorbent. - Gives retention not support. - Determine the level of