Complete Denture 1st Term PDF

# INTRODUCTION ## Prosthetics: The art and science of supplying artificial replacements for missing parts of the human body. ## Prosthodontics (Prosthetics dentistry): Is the dental specialty pertaining to the diagnosis, treatment planning, rehabilitation, and maintenance of the oral function, co...

# INTRODUCTION ## Prosthetics: The art and science of supplying artificial replacements for missing parts of the human body. ## Prosthodontics (Prosthetics dentistry): Is the dental specialty pertaining to the diagnosis, treatment planning, rehabilitation, and maintenance of the oral function, comfort, appearance, and health of patients with clinical conditions associated with missing or deficient teeth and/ or maxillofacial tissues using biocompatible substitutes. ## Prosthesis: An artificial replacement of an absent part of the human body. ## Dental prosthesis: An artificial replacement of one or more teeth (up to the entire dentition in either arch) and associated dento / alveolar structures. ## Fixed dental prosthesis: Any dental prosthesis that is luted, screwed, mechanically attached or otherwise securely retained to natural teeth, tooth roots, and/or dental implant abutments that furnish the primary support for the dental prosthesis. This may include replacement of one to sixteen teeth in each dental arch. ## Removable dental prosthesis Any dental prosthesis that replaces some or all teeth in a partially dentate arch (Partial removable dental prosthesis) or edentate arch (complete removable dental prosthesis). It can be removed from the mouth and replaced at will. ## Complete denture: A removable dental prosthesis that replaces the entire dentition and associated structures of the maxillae or mandible, called a complete removable dental prosthesis. ## Prosthodontics: - Fixed prosthodontics - Removable prosthodontics - Maxillofacial prosthodontics - Removable partial prosthodontics - Removable complete prosthodontics # Objectives of Complete denture: 1. Restoration of the function of mastication. 2. Restoration of the disturbed facial dimensions and contours (esthetics). 3. Preservation of the remaining tissues in health. 4. Satisfaction, pleasing, and comfort of the patient. 5. Correction of speech due to the loss of natural teeth. # General consideration in complete denture construction: 1. **From the operator:** - Certain degree of diagnostic skills. - Sound knowledge of biological and mechanical principles to provide a patient with a complete denture. - Certain degree of artistic ability to achieve good esthetic requirements. - Careful manipulation of dental materials and devices. 2. **From the patient:** - Co-operation with the dentist. - Some understanding of the limitation of prosthetic restoration. - Patience during the construction, learning, and adjustment of the new prosthesis. 3. **From the technician:** There should be co-operation between clinical and technical procedures. # Complete denture is composed of the following: 1. **Basal or impression surface:** The part of a denture that rests on the foundation tissue and to which teeth are attached. 2. **Denture occlusal surface:** The portion of the surface of a denture that makes contact with its antagonist. 3. **Denture polished surface:** The portion of the denture surface that extends in an occlusal direction from the border of the denture and include the palatal surface. It is usually polished and includes the buccal and lingual surfaces of the teeth. 4. **Denture border:** The margin of the denture base at the junction of the polished surface and the impression surface. 5. **Denture flange:** The part of the denture base that extends from the cervical ends of the teeth to the denture border. # ANATOMICAL LANDMARKS A good knowledge about the intra-oral landmarks for the maxillary and mandibular arch will help the clinician to carefully manage a patient, and it will act as positive guides to the limit of the impression and denture extensions. The intra-oral anatomical landmarks are divided into: 1. **Maxillary arch anatomical landmarks:** Which are divided into: - Supporting structures - Limiting structures - Relief areas ## a. Supporting structures: 1. Residual alveolar ridge 2. Maxillary tuberosity 3. Incisive papilla 4. Rugae area 5. Median palatal raghae 6. Canine eminence 7. Zygomatic process 8. Hamular notch 9. Torus palatinus Support is the resistance to the displacement towards the basal tissue or underlying structures, and it can be Primary stress bearing areas or supporting area represented by the horizontal portion of the hard palate lateral to the midline and Slopes of residual alveolar ridge and a Secondary stress bearing area or supporting areas represented by Rugae area and Maxillary Tuberosity. ### 1. Residual alveolar ridge: The bony process that remains after teeth have been lost is known as Residual alveolar ridge, which is covered by mucous membrane. The Residual alveolar ridge is considered to be as a primary stress bearing area. And it will produce the ridge fossa or groove in the impression or denture. #### Types of Residual alveolar ridge: - Flat - Rounded - V Shape - U Shape ### 2. Maxillary tuberosity It is the area of the alveolar ridge that extends distally from the second molar to the hamular notch. In some cases, it may be very large in size and not allow for proper placement of the denture, so may need surgical interferences. Maxillary tuberosity may be oversized, resorbed, or undercut areas; in case of oversized and undercut type surgical corrections may be needed. ### 3. Incisive papilla It is a pad of connective tissues that lies between the two central incisors on the palatal side overlying the incisive foramen of the nasopalatine duct where the nasopalatine nerves and vessels arise. In an edentulous mouth, it may lie close to the crest of the residual ridge. Relief over the Incisive papilla should be provided in the Denture to avoid pressure on the nerve and blood supply. ### 4. Rugae area These are raised areas of dense connective tissue in the anterior one-third of the palate. It aids in the formation of vocal sound, and it's also regarded as a secondary stress bearing area. ### 5. Median palatal raghae It overlies the medial palatal suture; extends from the incisive papilla to the distal end of the hard palate. The mucosa over these areas is usually tightly attached, and it's thin, the underlying bonny union being very dense and often raised, the palatal tori are located here if present. ### 6. Canine eminence It is a round elevation in the corner of the mouth; it represents the location of the root of the canine, which is helpful to be use as a guide for the arrangement of maxillary anterior teeth. ### 7. Zygomatic process It is located opposite to the 1st molar region, hard area found in the mouth that has been edentulous for a long time. Relief over this area may be required to prevent soreness of the underlying tissues. ### 8. Hamular notch It is a narrow cleft of loose connective tissue situated between the maxillary tuberosity and the pterygoid hamulus (approximately 2mm antero-posteriorly). It is used as boundary of the posterior border of maxillary denture. ### 9. Torus palatinus It is a hard bony enlargement that occurs in the midline of the roof of the mouth (hard palate). It is found in 20% of some patients; surgical correction may be needed if the tori are very large. ## b. Limiting structures: 1. Labial frenum 2. Buccal frenum 3. Labial vestibule 4. Buccal vestibule 5. Foveae palatinae 6. Vibrating line ### 1. Labial Frenum It's a fold of mucous membrane that extends from the mucosal lining of the upper lip to the labial surface of the residual ridge. The Frenum may be single or multiple, narrow or broad. It contains no muscle fibers and inserts in a vertical direction, which creates a maxillary labial notch in the maxillary impression or denture. ### 2. Buccal Frenum A fold or folds of mucous membrane vary in size and shapes. It extends from the buccal mucous membrane reflection area toward the slope or crest of the residual alveolar ridge. It contains no muscle fibers and its direction antero-posteriorly. It produces the maxillary buccal notch in the maxillary impression or denture, which must be broad enough because of the movement of the Frenum which is affected by some of the facial muscles as the orbicularis muscle pulls it forward while the buccinator muscle pulls it backward. ### 3. Labial vestibule It extends on both sides of the labial frenum to the buccal frenum, bounded by the upper lip and residual alveolar ridge. The reflection of the mucous membrane superiorly determines the height of the vestibule. It contains no muscle fibers. In the denture, the area that fills this space is known as the labial flange. ### 4. Buccal vestibule This is the space distal to the buccal frenum. It is bounded laterally by the cheek and medially by the residual alveolar ridge. The area of the denture that will fill this space is known as the buccal flange. The stability and retention of a denture are greatly enhanced if the vestibule space is properly filled with the flange distally. ### 5. Fovea palatinae These are two indentations on each side of the midline formed by a coalescence of several mucous gland ducts. They act as a guide in the location of the vibrating line of the posterior border of the denture. ### 6. Vibrating line An imaginary line drawn across the palate extended from one hamular notch to the other. It is not well defined as a line; therefore, it is better to describe it as an area rather than a line. The direction of the line varies according to the shape of the palate in the denture. The posterior border of the denture is known as the posterior palatal seal area. ## c. Relief Areas: 1. Incisive papilla 2. Mid-palatine raphe 3. Crest of the residual alveolar ridge 4. Cuspid eminence 5. Zygomatic Process # 2. Mandibular arch anatomical landmarks: This is divided into: - Supporting structures - Limiting structures - Relief areas ## Supporting structures: 1. Residual alveolar ridge. 2. Buccal shelf area. Support is the resistance to the displacement towards the basal tissue or underlying structures, the primary stress bearing area represented by the Buccal Shelf Area while the secondary stress bearing areas are represented by the Residual Alveolar Ridge. ### 1. Residual alveolar ridge: The bony process that remains after loss of teeth is known as residual alveolar ridge bone. The size and shape of the ridge varies from one patient to another. The bone of the crest of lower residual ridge being made of spongy bone, therefore, may not be favorable as a primary stress bearing area for the lower denture. It won't provide stability or support to the denture. ### 2. Buccal Shelf Area: It's bounded medially by the crest of residual ridge, laterally by the external oblique line, anteriorly by the buccal frenum, and distally by the retromolar pad. It is covered by compact bone, therefore, it serves as a primary stress bearing area for the lower denture. Because it is perpendicular to the vertical masticatory force, it provides support to the denture. ## b. Limiting structures: 1. Labial Frenum 2. Labial vestibule 3. Buccal frenum 4. Buccal vestibule 5. Retromolar pad 6. Lingual frenum 7 Alveololingual sulcus 8. Mental foramen 9. Genial tubercles 10. Torus Mandibularis 11. External oblique line 12. Mylohyoid ridge ### 1. Labial Frenum: It's a fold of mucous membrane not so pronounced as the maxillary labial frenum. It may be single or multiple, fine or broad, but it may contain a fibrous band attached to the orbicularis oris muscle, and therefore, it may be active in mastication. Proper fit around it maintains seal without soreness. ### 2. Labial vestibule: It extends from the labial frenum to the buccal frenum, limited inferiorly by the mucous membrane reflection internally by the residual ridge and labially by the lower lip. Overextension causes instability and soreness. Muscles attachment close to the crest of the ridge limits the denture flange extension. ### 3. Buccal Frenum: A fold of mucous membrane extended from the buccal mucous membrane reflection area toward the slopes of residual ridge. It may be single or multiple broad U-shaped or narrow V-shaped; it must have enough space in the denture, as it may be activated in function by the muscles. Adequate relief for muscle activity to get a proper denture seal. ### 4. Buccal vestibule: It extends from the buccal frenum to the distal end of the arch; it's bounded externally by the cheek and internally by the residual ridge. ### 5. Retromolar Pad: It's a pear-shaped area at the distal end of residual ridge. Histologically, it contains thin non-keratinized epithelium, loose areolar connective tissue, glandular tissue, fibers of buccinator, superior constrictor muscles, pterygomandibular raphe, and temporalis tendon. This pad must be covered by the denture to perfect the seal of the denture. The retromolar papilla is a small pear-shaped papilla just anterior to the retromolar pad, and it's dense fibrous connective tissue. ### 6. Lingual Frenum: It's a fold of mucous membrane that can be observed when the tongue is elevated, overlies the genioglossus muscle, extending along the floor of the mouth to the under surface of the tongue. It will produce the lingual notch in the denture. This frenum is activated when the tongue is moved, therefore it must be molded well in the impression to prevent displacement of the denture or ulceration of the tissue. ### 7. Alveololingual Sulcus: It's extended from the lingual frenum to the retromylohyoid curtain and bounded externally by the residual ridge and internally by the tongue. This space is filled by the lingual flange of the denture and can be divided into: - An **anterior portion:** It is extended from the lingual frenum to the premylohyoid fossa. - A **middle region:** It is extended from the premylohyoid fossa to the distal end of the mylohyoid ridge; here, the mylohyoid muscle is important in determining the contour of the lingual flange. - A **most posterior region:** Is the retromylohyoid space or fossa; it extends from the end of the mylohyoid ridge to retromylohyoid curtain, the lingual flange of the denture should extend laterally and fill the retromylohyoid fossa. The flange passes into the retromylohyoid fossa, and proper recording of the impression gives a typical S-form of the lingual flange. ### 8. Mental Foramen: It is located on the external surface of the mandible between the 1st and 2nd premolar area. In case of severe resorption of residual ridge, the denture should be relieved over the foramen to prevent pressure being applied on the mental nerves and blood vessels. ### 9. Genial tubercles: These are a pair of bony structures found anteriorly on the lingual side of the mandible. Prominent in a resorbed ridge, and adequate relief should be provided, or surgical correction may be needed. ### 10. Torus Mandibularis: These are bony exostosis composed of dense cortical bone covered by mucous membrane found on the lingual surface of the mandible at the premolar area and about 80% are bilateral. It has to be relieved or surgically corrected. ### 11. External Oblique Ridge: It's a ridge of dense bone extended from just above the mental foramen superiorly and distally to be continuous with the anterior border of the ramus. In some patients, this ridge becomes a guide for the termination of the buccal flange of the denture. ### 12. Mylohyoid Ridge: It's an irregular bony crest on the lingual surface of the mandible. This ridge is near the inferior border of the mandible in the incisor region, but it becomes higher posteriorly until it terminates near the 3rd molar area; it's the area where the mylohyoid muscle arises to the floor of the mouth. The border of the lingual flange may extend below the mylohyoid line if it slopes toward the tongue. ## c. Relief Areas: 1. Mental Foramen. 2. Torus mandibularis. 3. Genial tubercles. 4. Mylohyoid ridge. # CHAPTER III # IMPRESSION TRAYS AND IMPRESSION TECHNIQUES ## Definitions - **Dental Impression:** It's a negative reproduction of teeth and adjacent structures. - **Impression tray:** It's a device used to carry, confine, and control impression material. - **Cast:** It's a positive reproduction of the form of the tissues of the upper or the lower arch. ## Types of impressions | Type | Description | |-----------------------|--------------------------------------------------------------------------------------------| | Preliminary impression | To record the dimensions of the arch. | | Secondary impression | To record fine details of the arch. | | | | | **Purpose** | | | **Tray used** | Stock tray. | | | Special tray. | | **Used for** | Pouring of primary cast and construction of special tray. | | | Pouring of master cast construction of trial denture base and completion of the denture. | | **Materials used** | Impression compound or alginate. | | | Plaster impression material, ZnO, and Eugenol or rubber base. | | **Cast material** | Plaster of paris. | | | Dental stone. | | **Resulting cast** | Study (primary) cast. | | | Master cast. | # IMPRESSION TRAYS A tray is an instrument used to carry the impression material to the mouth. - **Component parts of tray:** 1. Body 2. Handle - **Types of tray:** 1. Stock tray 2. Special, custom tray - **STOCK TRAY:** Ready-made trays - For dentulous patients: Trays have flat floors, long flanges, and a straight handle - For edentulous patients: Trays have a rounded floor, short flanges, and an L-shaped handle - For partially edentulous patients: In the dentulous area, the tray has a flat floor and high flanges, and in the dentulous area, the floor is rounded, and the flanges are short - **Special tray:** - Custom tray, fabricated to suit the requirement of each patient. # BOXING OF IMPRESSIONS - **Definition:** It's a procedure of building up vertical walls around the impression periphery usually in wax. - **Advantages of boxing:** 1. Preserve borders of impression 2. Produce the desired size 3. Form the base of the cast 4. Time and material are conserved - **Methods of boxing:** 1. Wax bead boxing 2. Plaster and pumice boxing method # CHAPTER IV # POSTERIOR PALATAL SEAL AND RELIEF ## Posterior Palatal Seal **"Post-damming"** - **The post dam:** Is a slight elevation at the posterior border of the maxillary denture. - **The posterior palatal seal area:** Is a soft tissue area. - **Functions of the posterior palatal seal:** 1. The primary function is to achieve retention by increasing of upper denture. 2. Prevent food ingression under the denture base. 3. Reduce the gagging reflex. 4. It should be placed on the soft tissue area without putting any pressure on the underlying hard tissues. - **Post damming the lower dentures:** A lower denture may be post dammed at each distal extremity by slightly compressing the soft tissue forming the retromolar pad. - This area is often called the "posterior palatal seal". It is made to improve the retention of the denture. # Relief areas - **Definition:** Relief is the reduction or elimination of undesirable pressure from a specific region under the denture base. - **Functions of relief:** 1. Denture stability 2. Comfort for the patient - **Areas to be relieved:** 1. Hard bony areas 2. Sensitive areas - **Hard areas requiring relief:** - **In the maxilla:** 1. The median palatine raphe 2. Torus palatinus if present 3. Thin bony edges - **In the mandible:** 1. Thin, wiry, knife-edged ridges 2. Torus mandibularis if present - **Sensitive areas to be relieved:** - **In the maxilla:** 1. Incisive papilla 2. Prominent tuberositis and rugae - **In the mandible:** 1. Over the crest of thin ridge 2. Sharp mylohyoid ridge 3. Mental foramen in the premolar region of mandible - **METHOD OF RELIEF:** - **Automatic relief** - **Direct relief** # CHAPTER V # RETENTION AND STABILITY COMPLETE DENTURES - **Retention:** It is the resistance of the prosthesis to displacement in a vertical tissue away direction. - **Retention is the quality in a denture that resists:** - The force of gravity - The adhesiveness of food - The forces associated with jaw opening (muscle forces) - **Stability:** - It is the quality of the denture to be firm and constant in position. - It is the resistance against horizontal and rotational forces (anteroposterior, lateral displacement). - **FACTORS AFFECTING STABILITY:** 1. Retention Stable dentures should be retentive first. 2. Balanced occlusion Harmonious contact between maxillary and mandibular teeth. 3. Proper relief of hard areas 4. Ridge form A well-developed ridge with high vertical walls resists lateral forces. 5. Shape of palatal vault: A high arched palate offers good resistance to lateral stresses and increases denture stability. 6. Size of the tongue 7. The Polished Surface Contour: # CHAPTER VI # RELATION TO COMPLETE DENTURE MANDIBULAR MOVEMENTS AND THEIR CONSTRUCTION - **Possible mandibular movements:** 1. **Opening and closing:** Such movement can only be described when looking at the patient from a profile view. 2. **Protrusive movement:** 3. **Retrusive movement** 4. **Lateral (right and left) movements:** - **Why do we need to know mandibular movements?** The complete denture prosthesis is constructed to function in the dynamic conditions of the oral cavity. # CHAPTER FACE-BOW - **FACE-BOW** A caliper-like instrument used to record the spatial relationship of the maxillary arch to some anatomic reference point or points (in the cranium) and then transfer this relationship to an articulator. - **ARTICULATOR:** A mechanical device representing the jaws, to which casts may be attached, used in the making of dentures. - **TYPES OF FACE BOWS** 1. **Mandibular or kinematic face bow (hinge axis face bow):** - **It consists of:** - U-shaped bow - Clamp - Universal joint - Two pointed condylar rods - **Uses:** - Locate the exact terminal hinge axis before using the maxillary face bow. - Record the centric relation. 2. **Maxillary (arbitrary) face bow:** - It's a caliper-like device that is: - Used to record the relationship between the maxilla and the rotational axis (hinge axis) of the mandible. - Transfer this relation from the patient to the articulator. - It orients the maxillary cast in the same relationship to the opening axis of the articulator. - It's a U-shaped bow. The following parts are connected to it: - A bite fork - Two tow posterior reference point indicators - An anterior reference point indicator