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# Introduction to orthopedic dentistry and its scope Orthopedic dentistry is a specialized field within dentistry focused on restoring the form, function, and aesthetics of teeth and jaws using prosthetic constructions [1](#page=1). ### 1.1 Definition and scope Orthopedic dentistry is defined as the branch of dentistry concerned with restoring the anatomical form, function, and aesthetics of teeth, dentition, and jaws through the use of orthopedic constructions (prostheses) [1](#page=1). ### 1.2 Sub-disciplines of orthopedic dentistry The field of orthopedic dentistry encompasses several key sub-disciplines: * Orthopedic treatment of defects in the hard tissues of teeth [1](#page=1). * Orthopedic treatment of partial tooth loss [1](#page=1). * Orthopedic treatment of complete edentulism (total tooth loss) [1](#page=1). * Maxillofacial orthopedics [1](#page=1). * Materials science relevant to prosthetics [1](#page=1). * Dental technology and laboratory procedures [1](#page=1). ### 1.3 Goals of orthopedic dentistry The primary goals of orthopedic dentistry include: * Restoration of masticatory (chewing) function [1](#page=1). * Restoration of speech function [1](#page=1). * Restoration of aesthetic appearance [1](#page=1). * Maintenance of the health of the stomatognathic system (the complex of teeth, jaws, muscles, and nerves involved in chewing and speaking) [1](#page=1). ### 1.4 Objectives of orthopedic dentistry The specific objectives that orthopedic dentistry aims to achieve are: * Restoration of the integrity of the dental arches [1](#page=1). * Normalization of occlusion (the way the upper and lower teeth fit together) [1](#page=1). * Prevention of further dental deformities [1](#page=1). * Improvement of the patient's quality of life [1](#page=1). ### 1.5 Preventive aspects of orthopedic dentistry A significant aspect of orthopedic dentistry is its preventive direction, which involves: * Early prosthodontic intervention [2](#page=2). * Preservation of abutment teeth (teeth supporting a dental prosthesis) [2](#page=2). * Prevention of periodontal overload [2](#page=2). * Prevention of secondary dental arch deformities [2](#page=2). * Rational planning of orthopedic treatment [2](#page=2). > **Tip:** Understanding the preventive aspects is crucial as it highlights how orthopedic dentistry aims to maintain oral health and prevent future complications, not just treat existing issues. ### 1.6 Stages of development in Ukraine The development of orthopedic dentistry in Ukraine can be broadly categorized into distinct periods: * **Pre-revolutionary period:** Characterized by empirical methods of prosthodontics [2](#page=2). * **Soviet period:** Marked by the formation of a scientific school and standardization of prostheses [2](#page=2). * **Modern stage:** Characterized by the integration of digital technologies, implantology, and CAD/CAM systems [2](#page=2). #### 1.6.1 Contributions of Ukrainian scientists Ukrainian scholars have made significant contributions to the field, including: * Formation of a national school of orthopedic dentistry [2](#page=2). * Development of methods for removable and fixed prosthodontics [2](#page=2). * Research into functional occlusion [2](#page=2). * Implementation of biocompatible materials [2](#page=2). Prominent dental schools contributing to these advancements include those in Kyiv, Lviv, Kharkiv, and Odesa [2](#page=2). --- # Anatomical and functional considerations in the jaw and dental system This section explores the anatomical characteristics of the jaws and teeth, the biomechanics of the dentition, and the role of associated muscles and joints in oral functions. ### 5.1 Maxillary and mandibular anatomy The **upper jaw (maxilla)** is characterized by its immobility porous bone structure, and suitability as a prosthetic base. In contrast, the **lower jaw (mandible)** is a mobile bone that is denser and possesses a joint head [4](#page=4) [5](#page=5). ### 5.2 Dental anatomy and physiology Teeth serve several crucial functions, including biting and incising food, grinding and masticating food, contributing to speech formation, and playing a significant role in aesthetics. The dental arches form distinct shapes: the upper arch typically resembles a semi-ellipse, while the lower arch forms a parabola [5](#page=5). ### 5.3 Dental arch stability factors The stability of the dental arches is influenced by several factors [6](#page=6): * The shape of the tooth roots [6](#page=6). * The condition of the periodontium (tissues supporting the teeth) [6](#page=6). * The presence and integrity of contact points between adjacent teeth [6](#page=6). * The influence of opposing teeth (antagonists) [6](#page=6). * The balance of the masticatory muscles [6](#page=6). ### 5.4 Prosthetic and occlusal planes The **prosthetic plane** is an imaginary plane used as a reference for the placement of artificial teeth. The **occlusal plane** is the plane formed by the biting surfaces of the teeth when they come into contact [6](#page=6). Within the occlusal plane, there are specific curves that contribute to efficient chewing: * **Spee's curve** is the sagittal curve of the occlusal plane [6](#page=6). * **Wilson's curve** is the transverse curve of the occlusal plane [6](#page=6). The dental system also involves different arcs: * The **dental arch** [6](#page=6). * The **alveolar arch** [6](#page=6). * The **basal arch** [6](#page=6). ### 5.5 Temporomandibular joint (TMJ) The temporomandibular joint (TMJ) is a critical component of the jaw system, enabling a range of movements. Its structure includes [7](#page=7): * The **articular head** (condyle of the mandible) [7](#page=7). * The **articular fossa** (glenoid fossa of the temporal bone) [7](#page=7). * The **articular disc** [7](#page=7). * The **joint capsule** [7](#page=7). The TMJ is responsible for several essential functions: * Opening and closing the mouth [7](#page=7). * Chewing [7](#page=7). * Speech [7](#page=7). ### 5.6 Muscles of the maxillofacial region The muscles of the maxillofacial region can be broadly categorized into masticatory and facial muscles. **Masticatory muscles** are primarily responsible for jaw movements during chewing. These include [7](#page=7) [8](#page=8): * The **masseter muscle** [7](#page=7). * The **temporalis muscle** [7](#page=7). * The **medial pterygoid muscle** [7](#page=7). * The **lateral pterygoid muscle** [7](#page=7). **Facial (mimetic) muscles** are involved in facial expressions, speech, and retaining food within the oral cavity. Key facial muscles include [8](#page=8): * The **orbicularis oris muscle** [8](#page=8). * The **buccinator muscle** [8](#page=8). * The **muscles of the lips and cheeks** [8](#page=8). ### 5.7 Muscles of the dento-alveolar system and masticatory musculature The dento-alveolar muscular system is a collective term for the muscles that facilitate lower jaw movements, chewing, swallowing, speech, and facial mimicry. This system encompasses the masticatory muscles, facial muscles, and the muscles of the tongue and floor of the mouth [8](#page=8). The **masticatory musculature** consists of the masseter, temporalis, medial pterygoid, and lateral pterygoid muscles. These muscles are innervated by the trigeminal nerve [8](#page=8). The primary functions of the masticatory muscles include: * Elevation and depression of the lower jaw [8](#page=8). * Protrusion (moving forward) and retraction (moving backward) of the lower jaw [8](#page=8). * Lateral movements of the lower jaw during chewing [8](#page=8). ### 5.8 Absolute force of masticatory muscles, chewing pressure, force, and efficiency **Absolute force of masticatory muscles** refers to the maximum contractile force a muscle can generate, irrespective of functional conditions. **Chewing force** is the force exerted during tooth contact in the process of chewing. This force can be measured in Newtons or kilogram-force [9](#page=9). **Chewing pressure** is defined as the force applied per unit area of the tooth's chewing surface. Its units of measurement are N/cm² or kgf/cm². **Chewing efficiency** quantifies the ability of the dento-alveolar system to break down food over a specific period, usually expressed as a percentage [9](#page=9). Methods for assessing these parameters include: * Gnathodynamometry [9](#page=9). * Electromyography [9](#page=9). * Chewing tests (chewing probes) [9](#page=9). ### 5.9 Biomechanics of the dento-alveolar system and lower jaw movements The biomechanics of the dento-alveolar system investigates the interactions between teeth, the periodontium, muscles, and the TMJ during functional loads. The lower jaw exhibits three primary types of movements [9](#page=9): * **Vertical movements:** Opening and closing the mouth [9](#page=9). * **Sagittal movements:** Protrusion (moving forward) and retrusion (moving backward) of the lower jaw [9](#page=9). * **Transverse movements:** Lateral shifts, characteristic of the chewing act [9](#page=9). ### 5.10 Chewing and its phases Chewing is a complex reflex act involving the mechanical processing of food in the oral cavity. The process is facilitated by the coordinated action of teeth, muscles, the tongue, and salivary glands. The phases of chewing are [10](#page=10) [9](#page=9): 1. **Food intake and insertion into the mouth** [10](#page=10). 2. **Food fragmentation** [10](#page=10). 3. **Formation of the food bolus** [10](#page=10). 4. **Swallowing** [10](#page=10). ### 5.11 Periodontium: structure, functions, and resilience The periodontium is the complex of tissues surrounding a tooth that anchors it within the alveolar bone. Its structure comprises [10](#page=10): * Gums (gingiva) [10](#page=10). * The periodontal ligament [10](#page=10). * Root cementum [10](#page=10). * Alveolar bone [10](#page=10). The functions of the periodontium include: * **Support** [10](#page=10). * **Shock absorption** [10](#page=10). * **Trophic (nutritional) supply** [10](#page=10). * **Protection** [10](#page=10). * **Sensory reception** [10](#page=10). The periodontium exhibits varying degrees of resilience to different forces. It is most resistant to vertical loads, less so to horizontal loads, and least to oblique forces [10](#page=10). ### 5.12 Articulation and occlusion: physiological bites **Occlusion** refers to the static contact relationship between the upper and lower teeth. **Articulation** describes the dynamic contacts between teeth during lower jaw movements [10](#page=10) [11](#page=11). There are three main types of occlusion: * **Central occlusion** [11](#page=11). * **Anterior occlusion** [11](#page=11). * **Lateral occlusion** [11](#page=11). A **bite (occlusal relationship)** is defined by the characteristic way teeth occlude in central occlusion. **Physiological bites** ensure proper function of chewing, speech, and aesthetics. These include [11](#page=11): * Orthognathic bite [11](#page=11). * Edge-to-edge bite [11](#page=11). * Biprognathic bite [11](#page=11). * Prognathic bite [11](#page=11). ### 5.13 Pathological bites A **pathological bite** represents a disruption in the relationship between the dental arches. Key types of pathological bites include [11](#page=11): * Distal bite [11](#page=11). * Mesial bite [11](#page=11). * Deep bite [11](#page=11). * Open bite [11](#page=11). * Crossbite [11](#page=11). The consequences of pathological bites can be significant, including: * Reduced chewing efficiency [11](#page=11). * Overloading of the periodontium [11](#page=11). * Dysfunction of the temporomandibular joint (TMJ) [11](#page=11). * Defects in speech and aesthetics [11](#page=11). --- # Diagnostic methods and patient examination in orthopedic dentistry This section outlines the systematic approach to examining patients in orthopedic dentistry, encompassing subjective and objective assessments, along with supplementary diagnostic techniques. ### 3.1 Principles of patient examination Patient examination is a systematic process of data collection crucial for establishing a diagnosis, planning orthopedic treatment, and formulating a prognosis. The examination follows a strict sequence: subjective assessment, followed by objective assessment, then additional diagnostic methods, and finally, the formulation of a diagnosis [12](#page=12) [13](#page=13). ### 3.2 Methods of examination The primary methods of examination in orthopedic dentistry can be broadly categorized into three groups [13](#page=13): 1. Clinical methods 2. Additional (special) methods 3. Laboratory and instrumental methods Clinical methods hold a leading role in orthopedic dentistry practice [13](#page=13). ### 3.3 Subjective examination Subjective examination involves gathering patient complaints and medical history (anamnesis) [13](#page=13). #### 3.3.1 Patient complaints Common patient complaints in orthopedic dentistry include [13](#page=13): * Pain * Chewing difficulties * Aesthetic defects * Speech impairments * Temporomandibular joint (TMJ) discomfort #### 3.3.2 History of the disease (anamnesis of the disease) This part of the history focuses on the onset and progression of the patient's current condition and relevant past dental history. Key areas include [13](#page=13): * When symptoms appeared * Causes of tooth loss * Previous treatments and prosthodontics * Duration of prosthesis use #### 3.3.3 Medical history (anamnesis of life) This component gathers information about the patient's general health and lifestyle that may influence dental treatment. It covers [14](#page=14): * General diseases * Harmful habits * Professional factors * Allergic reactions The subjective examination is instrumental in guiding the direction of further diagnostic steps [14](#page=14). ### 3.4 Objective examination in orthopedic dentistry Objective examination is conducted through visual inspection, palpation, and functional tests [14](#page=14). #### 3.4.1 General examination The general examination assesses the patient's overall condition, body type, posture, and body symmetry [14](#page=14). #### 3.4.2 External examination of the maxillofacial region This involves evaluating the facial features and surrounding structures [14](#page=14): * Face shape * Symmetry * Skin condition * Lower jaw position * Nasolabial fold prominence #### 3.4.3 Examination of the temporomandibular joint (TMJ) Key aspects of the TMJ examination include [14](#page=14): * Palpation of the joints * Presence of pain * Auditory signs such as crepitus or clicking * Synchronicity of jaw movements #### 3.4.4 Character and degree of mouth opening This assesses the range and quality of mandibular movement [15](#page=15): * Whether mouth opening is free or restricted * Deviation of the lower jaw during opening * Amplitude of mandibular movements #### 3.4.5 Intraoral examination The intraoral examination focuses on the oral cavity's structures [15](#page=15): * Condition of the teeth * Number and location of dental arch defects * Shape of the dental arches * Occlusion characteristics #### 3.4.6 Examination of teeth and dental arches Specific attention is paid to the teeth and their supporting structures [15](#page=15): * Caries and non-carious lesions * Tooth mobility * Tooth wear * Presence of fillings and crowns #### 3.4.7 Examination of the oral mucosa The condition of the soft tissues within the mouth is assessed for signs of health or pathology [16](#page=16): * Color * Moisture content * Elasticity * Presence of inflammation, trauma, or hyperplasias ### 3.5 Additional diagnostic methods (functional and instrumental) These methods are employed to refine the diagnosis and evaluate the functional status of the dentition and stomatognathic system [16](#page=16). #### 3.5.1 Electromyography (EMG) EMG investigates the bioelectrical activity of the masticatory muscles, providing insights into their coordination and loading [16](#page=16). #### 3.5.2 Rheography This technique assesses blood supply to the periodontal tissues and oral mucosa [16](#page=16). #### 3.5.3 Masticatiography Masticatiography studies the nature and rhythm of chewing movements, and evaluates chewing efficiency [16](#page=16). #### 3.5.4 Electroodontodiagnosis (EOD) EOD determines tooth pulp vitality by measuring its response to electrical current [16](#page=16). #### 3.5.5 Occlusography This method evaluates tooth contacts during various occlusal phases and identifies premature contacts [16](#page=16). ### 3.6 Additional methods: study of diagnostic models Diagnostic models are gypsum replicas of the dental arches, created from impressions [16](#page=16). #### 3.6.1 Purpose of studying diagnostic models The study of diagnostic models is essential for several aspects of treatment planning [17](#page=17): * Analysis of dental arch form * Occlusion assessment * Identification of dental arch defects * Prosthetic treatment planning #### 3.6.2 Significance of diagnostic models Studying diagnostic models allows for analysis outside the oral cavity, precise measurements, simulation of future prosthetic designs, and evaluation of treatment prognosis [17](#page=17). ### 3.7 Static methods for determining chewing efficiency Static methods evaluate the quantity and arrangement of functionally complete teeth without considering the actual chewing process [17](#page=17). #### 3.7.1 Agapov's method Chewing efficiency is determined by the number of preserved teeth and their functional value. Each tooth is assigned a specific coefficient based on its role in mastication. The sum of coefficients for functioning teeth is compared to a norm, considered 100% [17](#page=17). #### 3.7.2 Oksman's method This method considers not only the number of teeth but also their antagonists. A tooth without an antagonist is deemed non-functional. This method provides a more accurate reflection of real chewing efficiency [17](#page=17). > **Tip:** Both Agapov's and Oksman's methods are used for preliminary assessment of chewing function and prosthetic planning [17](#page=17). ### 3.8 Radiographic methods of examination in orthopedic dentistry Radiographic methods are vital for assessing the condition of teeth, roots, periodontium, bone tissue, and the TMJ [18](#page=18). #### 3.8.1 Intraoral radiography This is used to evaluate tooth roots, periapical tissues, and the quality of root canal fillings [18](#page=18). #### 3.8.2 Orthopantomography (OPTG) OPTG provides a panoramic view of the dental arches, jaws, and TMJs, allowing for an assessment of the overall state of the dentition and maxillofacial system [18](#page=18). #### 3.8.3 Computed tomography (CT) CT provides a three-dimensional image and is utilized for planning dental implant surgery, complex prosthodontic cases, and assessing bone volume [18](#page=18). #### 3.8.4 Zonography This technique is applied for detailed examination of the TMJ in functional positions [18](#page=18). #### 3.8.5 Contrast radiography Contrast radiography is used for the investigation of soft tissues and the articular disc of the TMJ [18](#page=18). ### 3.9 Medical history in orthopedic dentistry The medical history is an official medical document that records the entire process of patient examination and treatment [18](#page=18). #### 3.9.1 Main sections of the medical history The primary sections of a medical history in orthopedic dentistry include [18](#page=18): * Passport data * Complaints * History of the disease * Medical history of life * Objective status --- # Materials and technologies in the fabrication of dental prostheses This topic explores the diverse materials and technological stages involved in creating both fixed and removable dental prostheses, covering everything from initial impressions to final material properties [19](#page=19) [20](#page=20) [21](#page=21) [22](#page=22) [23](#page=23) [24](#page=24) [25](#page=25) [26](#page=26) [27](#page=27) [28](#page=28) [29](#page=29) [30](#page=30) [31](#page=31) [32](#page=32). ### 4.1 Types of Dental Prostheses Dental prostheses are orthopedic structures designed to replace missing teeth and defects in the dental arch [19](#page=19). #### 4.1.1 Fixed Prostheses Fixed prostheses are designs permanently attached to the oral cavity and cannot be removed by the patient. They are affixed to natural teeth or implants, offering high functionality and aesthetics, and ensuring even load distribution. Examples include inlays, onlays, crowns, and bridge prostheses [19](#page=19). #### 4.1.2 Removable Prostheses Removable prostheses are structures that patients can independently remove and reinsert. They are used in cases of partial or complete edentulism to restore chewing, speech, and aesthetic functions. These prostheses are supported by the oral mucosa, teeth, or implants. They are categorized as partial or complete removable prostheses [20](#page=20). ### 4.2 Technological Stages in Prosthesis Fabrication The fabrication process for both fixed and removable prostheses involves distinct clinical and laboratory stages. #### 4.2.1 Fabrication of Fixed Prostheses The primary stages for fixed prostheses include: * Examination and planning [20](#page=20). * Tooth preparation [20](#page=20). * Impression taking [20](#page=20). * Fabrication of working models [20](#page=20). * Design modeling [20](#page=20). * Prosthesis fabrication [20](#page=20). * Try-in [20](#page=20). * Fixation in the oral cavity [20](#page=20). #### 4.2.2 Fabrication of Removable Prostheses The fabrication of removable prostheses is a multi-step process: * Clinical examination [21](#page=21). * Taking anatomical impressions [21](#page=21). * Fabrication of custom trays [21](#page=21). * Functional impressions [21](#page=21). * Determination of occlusion [21](#page=21). * Setting of artificial teeth [21](#page=21). * Try-in [21](#page=21). * Final fabrication and delivery of the prosthesis [21](#page=21). ### 4.3 Impression Materials Impression materials are used to create accurate negative reproductions of oral tissues [21](#page=21). #### 4.3.1 Classification and Requirements of Impression Materials Impression materials are broadly classified into elastic and inelastic types [21](#page=21). Key requirements for impression materials include: * Accuracy in replicating relief [22](#page=22). * Biocompatibility [22](#page=22). * Sufficient elasticity (for elastic materials) [22](#page=22). * Dimensional stability [22](#page=22). * Ease of use [22](#page=22). #### 4.3.2 Impression Trays Impression trays are used to hold the impression material during the recording of the oral structures. Trays can be standard or custom-made, and constructed from metal or plastic. The choice of tray depends on the jaw size, type of impression, and the impression material used. A correctly chosen tray should fully cover the intended area without exerting pressure [22](#page=22). #### 4.3.3 Impression Taking Methodology and Quality Criteria The methodology involves preparing the oral cavity, selecting the appropriate tray, mixing the material, inserting the tray into the mouth, and stabilizing it until the material hardens [22](#page=22). Quality criteria for impressions include: * Clear reproduction of anatomical structures [23](#page=23). * Absence of tears and voids [23](#page=23). * Correctly formed borders [23](#page=23). * Shape stability [23](#page=23). #### 4.3.4 Rigid Impression Materials Rigid impression materials are inelastic and transition into a crystalline state after setting, meaning they do not recover their shape after deformation. Their composition typically includes calcium salts (gypsum), water, and modifying additives. These materials harden through crystallization, providing a sufficiently accurate reproduction of tissues, but are brittle and inelastic. They are indicated for impressions of edentulous jaws without undercuts. Disadvantages include brittleness, inability to be used with undercuts, and a risk of tissue trauma [23](#page=23). #### 4.3.5 Zinc Oxide-Eugenol Impression Materials Zinc oxide-eugenol materials are inelastic, two-component materials used for precise functional impressions. One paste contains zinc oxide, while the other contains eugenol, oils, and setting accelerators. The material hardens via a chemical reaction, offering high accuracy, minimal shrinkage, and excellent reproduction of mucosal relief. Advantages include high accuracy, dimensional stability, and ease of use. Disadvantages are brittleness, the irritant effect of eugenol, and inelasticity. They are used for functional impressions for complete removable dentures and for control impressions [23](#page=23) [24](#page=24). #### 4.3.6 Thermoplastic Impression Materials Thermoplastic materials change their physical state under the influence of temperature. They typically consist of wax, resins, paraffin, and fillers. These materials soften upon heating and harden upon cooling, becoming inelastic after setting. Advantages include reusability, possibility of correction, and ease of modeling. Disadvantages include deformation upon cooling, low accuracy, and unsuitability for complex anatomical situations. Their applications include preliminary impressions, fabrication of custom trays, and functional tests [24](#page=24) [25](#page=25). #### 4.3.7 Alginate Impression Materials Alginate materials are elastic, hydrocolloid materials widely used in clinical practice. Their composition includes alginates, calcium salts, fillers, and setting retarders. They harden via a chemical reaction and are elastic but have limited dimensional stability. Advantages include ease of use, elasticity, patient comfort, and affordability. Disadvantages are shrinkage upon drying and the necessity for immediate model pouring. They are used for anatomical impressions, diagnostic models, and removable prostheses [25](#page=25) [26](#page=26). #### 4.3.8 Silicone Impression Materials Silicone materials are high-accuracy elastomers. They are divided into condensation and addition types. Advantages include high accuracy, elasticity, dimensional stability, and the ability to pour multiple models from a single impression. Disadvantages include high cost and sensitivity to moisture (for some types). Their applications are in fixed prosthodontics, implantology, and for precise functional impressions [26](#page=26) [27](#page=27). #### 4.3.9 Polyether Impression Materials Polyether materials are elastic materials offering high accuracy and stiffness. Advantages include excellent accuracy, good fluidity, and dimensional stability. Disadvantages are increased stiffness, difficulty in removal from the mouth, and potential discomfort for the patient. They are used for precision impressions in fixed prosthodontics and implantology [27](#page=27). ### 4.4 Complications in Impression Taking The main complications during impression taking can include asphyxia, thermal burns, and allergic reactions. These can be caused by an excess of material, incorrect temperature, or individual patient sensitivity. Prevention involves proper material selection, control of quantity and temperature, and a thorough patient history. Management includes immediate removal of the material, emergency aid, and symptomatic treatment [27](#page=27) [28](#page=28). ### 4.5 Disinfection, Storage, and Transportation of Impressions Impressions must undergo mandatory disinfection after removal from the oral cavity. Methods include spraying or immersion in a disinfectant solution. Impressions should be stored in a moist environment and transported in sealed containers [28](#page=28). ### 4.6 Gypsum Models of the Jaws Gypsum models are precise replicas of the dental arches and the denture base area. They can be diagnostic, working, verification, or auxiliary models. Their purposes include bite analysis, treatment planning, and prosthesis fabrication [29](#page=29). ### 4.7 Plastics in Prosthodontics Plastics are polymer materials extensively used in the fabrication of dental prostheses. They are classified as thermoplastic and thermosetting. Their chemical composition includes a polymer, monomer, initiators, fillers, and colorants. Properties include strength, aesthetics, biocompatibility, and processability. The preparation technology involves mixing polymer with monomer, followed by swelling, maturation, and polymerization stages [29](#page=29). ### 4.8 Dental Porcelain Dental porcelain is a ceramic material used for fabricating aesthetic prosthetic restorations. It is an inorganic, non-metallic material that achieves high strength and transparency, similar to tooth enamel, after firing. Properties include high aesthetics, biocompatibility, chemical inertness, wear resistance, and color stability. Its drawbacks are brittleness and low impact strength. It is used for veneers, inlays, onlays, crowns, and for veneering metal-ceramic restorations [30](#page=30). ### 4.9 Zirconium Oxide-Based Materials Zirconium oxide is a modern, high-strength ceramic material for prosthodontics. It belongs to all-ceramic materials and is manufactured using CAD/CAM technologies. Properties include high strength and fracture resistance, biocompatibility, absence of corrosion, and good aesthetic qualities. Disadvantages include processing complexity and high cost. It is used for the frameworks of crowns and bridges, abutments, and all-ceramic restorations [30](#page=30). ### 4.10 Noble Metals and Their Alloys Noble metals are corrosion and oxidation-resistant metals. These include gold, platinum, palladium, and their alloys. Their physical properties include high corrosion resistance, plasticity, casting accuracy, and good biocompatibility. They are used for fabricating inlays, crowns, metal-ceramic prosthesis frameworks, and bridge constructions [30](#page=30) [31](#page=31). ### 4.11 Non-Noble Metals and Their Alloys Non-noble metals are less corrosion-resistant but possess high mechanical strength. Common alloys include cobalt-chromium, nickel-chromium, and titanium. Their physical properties include high strength, hardness, wear resistance, and lower cost. Disadvantages include potential allergic reactions and processing difficulty. They are used for the frameworks of removable partial dentures (burs), metal-ceramic crowns and bridges, and orthopedic elements [31](#page=31). ### 4.12 Modeling Materials (Wax Compositions) Modeling materials are wax compositions used to create models of future prosthetic structures. Their physical properties include plasticity when heated, hardness when cooled, minimal shrinkage, and ease of processing. They are used for modeling crowns, inlays, prosthesis frameworks, and for fabricating wax patterns and bases [31](#page=31). ### 4.13 Dental Cements for Prosthetic Fixation Dental cements are materials used for the permanent or temporary fixation of prosthetic constructions. They provide the connection between the prosthesis and the tooth tissues. Properties include adhesion to tooth tissues, sufficient strength, biocompatibility, and hermetic sealing. They vary in strength and duration of fixation. They are used for fixing crowns, bridges, inlays, and prosthetic structures on teeth and implants [32](#page=32). ### 4.14 Abrasive, Polishing, and Isolating Materials Abrasive materials are used for grinding and shaping prosthetic constructions, possessing high hardness and wear resistance. Polishing materials are used to impart smoothness and luster to prosthesis surfaces, reducing roughness and plaque accumulation. Isolating materials are designed to prevent the bonding of different materials during laboratory and clinical procedures [32](#page=32). --- ## Common mistakes to avoid - Review all topics thoroughly before exams - Pay attention to formulas and key definitions - Practice with examples provided in each section - Don't memorize without understanding the underlying concepts

| Term | Definition | |------|------------| | Orthopedic dentistry | A branch of dentistry focused on restoring the anatomical form, function, and aesthetics of teeth, dental arches, and jaws using prosthetic constructions. | | Prosthetic constructions (prostheses) | Devices used to replace missing teeth or restore damaged teeth and jaw structures, designed to mimic natural form and function. | | Partial adentia | The condition of having one or more missing teeth within an arch, requiring partial prosthetic replacement. | | Complete adentia | The complete loss of all teeth in one or both dental arches, necessitating full prosthetic solutions. | | Maxillofacial orthopedics | A sub-discipline within orthopedic dentistry that deals with the prosthetic restoration and management of defects in the jaws and facial structures. | | Occlusion | The act or condition of the teeth of the upper and lower jaws coming together; the way teeth fit together when the mouth is closed. | | Temporomandibular joint (TMJ) | The joint connecting the mandible (lower jaw) to the temporal bone of the skull, crucial for jaw movement, chewing, and speech. | | Dental arch | The curved structure formed by the teeth in each jaw; typically described as a semi-ellipse (upper) and a parabola (lower). | | Mastication | The process of chewing food in preparation for swallowing. | | Periodontium | The specialized tissues that surround and support the teeth, including the gums, periodontal ligament, cementum, and alveolar bone. | | Articulation | The dynamic contacts between teeth during the movements of the mandible, distinct from the static position of occlusion. | | Physiological bites | The normal, healthy ways teeth occlude, ensuring proper function and aesthetics, such as orthognathic, direct, and prognathic types. | | Pathological bites | Abnormal occlusal relationships that disrupt normal jaw function, leading to issues like reduced chewing efficiency or TMJ problems. | | Asepsis | A set of practices and procedures designed to prevent the introduction or spread of microorganisms, thereby avoiding infection. | | Antisepsis | Measures taken to destroy or inhibit the growth of microorganisms on living tissue to prevent infection. | | Impression materials | Dental materials used to create a negative replica (impression) of oral structures, which is then used to fabricate dental prostheses. | | Diagnostic models | Plaster or stone replicas of the patient's dental arches and surrounding oral tissues, used for diagnosis and treatment planning. | | Working models | Detailed replicas of the prepared teeth and surrounding tissues, used directly in the laboratory to fabricate dental prostheses. | | CAD/CAM | Computer-Aided Design/Computer-Aided Manufacturing; digital technology used to design and produce dental restorations with high precision. | | Biocompatibility | The ability of a material to perform with an appropriate host response in a specific application; essential for dental materials. | | Veneers | Thin, custom-made shells, usually made of porcelain or composite resin, designed to cover the front surface of teeth for aesthetic improvement. | | Inlays | A dental restoration made outside the tooth to fit a prepared cavity within a tooth, typically made of gold, porcelain, or composite. | | Onlays | A dental restoration that covers one or more cusps of a tooth, also known as a partial crown. | | Crowns | Dental restorations that cover the entire visible surface of a tooth, used to restore its shape, size, strength, and appearance. | | Bridgework (bridge prostheses) | Dental prostheses used to replace one or more missing teeth by spanning the gap and being attached to adjacent teeth or implants. | | Removable prostheses | Dental appliances that can be removed and reinserted by the patient, used to replace missing teeth and surrounding tissues. | | Denture | A removable dental prosthesis that replaces missing teeth and some of the surrounding gum tissue. | | Impression trays | Devices used to hold impression material in the mouth and obtain an accurate replica of oral structures. | | Gypsum models | Models made from dental plaster or stone, used to represent the patient's oral anatomy for diagnosis and fabrication of prosthetics. | | Dental cements | Materials used to permanently or temporarily bond dental restorations to natural teeth or implants. | | Zirconia | A strong, tooth-colored ceramic material often used for dental crowns, bridges, and implant abutments due to its strength and aesthetics. |