Occlusal Analysis and Force Finishing

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© Springer Nature Switzerland AG 2021

P. Jain, M. Gupta (eds.)Digitization in Dentistryhttps://doi.org/10.1007/978-3-030-65169-5_8

8. Digital Occlusal Analysis and Force Finishing

Sushil Koirala1, 2  
(1)

Vedic Smile Pvt. Ltd, Kathmandu, Nepal
(2)

The Department of Vedic Smile Dentistry, National Dental Hospital Ltd, Kathmandu, Nepal
 
Keywords

Vedic Smile DentistryForce FinishingOcclusal force disordersOcclusal harmonyOcclusionTMJA Harmony

8.1 Introduction

Dentistry is one of the fastest-growing field in medical science due to the recent advancement in digital and materials science and technology. As dentistry progresses into the digital world, the successful integration of automation and new technology will continue to offer more competent, precise, and healthy treatment modalities for the patients. However, we need to understand clearly that any new science, technologies, and protocols in dentistry will only be successful if they are embraced and incorporated with a vision of achieving Quality of Life (QOL) through dentistry. In this regard, the contemporary dentistry demands well-considered concepts and treatment protocols that provide a simple, comprehensive, patients-centric, and minimally invasive methodology to achieve the long-term optimum results in terms of health, function, and aesthetics and high patient satisfaction at minimal biological cost. There are various practice philosophies in dentistry and, the author believes that the dentist has the full right to adopt the practice philosophy that he or she prefers. However, it is always advisable to apply oneself to understanding, analyzing, and comparing this philosophy with others.

Since early years of career, the author has been embracing the “Vedic Smile Dentistry,” a holistic dental care and treatment approach, which is based on the Vedic philosophy of consciousness and natural harmony (Fig. 8.1), and the Smile Design Wheel (Fig. 8.2) protocol in daily practice. The Smile Design Wheel protocol [1] includes the components of psychology, health, function, and aesthetics (PHFA), which can guide clinicians to preserve tooth structure, prolong tooth longevity, reduce treatment cost, lessen the number of restoration replacement cycles in a lifetime, increase patient confidence and trust in the clinician, while enhancing the image of the profession during dental treatment. The wheel especially focuses on function as one of the critical factors for long-term clinical success, as it is directly related to the occlusion, which generates various forces and stresses that occur within the masticatory system of a patient.

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Fig. 8.1

Vedic Smile practice approach and its key components: holistic care, good dentist, right protocol, and suitable technology

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Fig. 8.2

Smile Design Wheel protocol, suggesting to consider psychology, health, function, and aesthetic components of the patient during diagnosis, treatment, and follow-up visits

This chapter focuses on the role of dental occlusion, occlusal forces, and occlusal forces diseases (OFD) that a dentist may encounter in daily clinical dentistry, and details how to integrate the Force Finishing concept and its protocol to diagnose, prevent, and manage the occlusal force disorders in clinical practice.

8.2 Dental Occlusion: The Foundation of Vedic Smile Dentistry (VSD) Approach

Dental occlusion has been, and is still to some extent, a controversial discipline, as there are numerous questions related to occlusion which have not yet been answered with scientific certainty [2]. There are many diverse and polarized opinions regarding this subject that are seldom based on current scientific evidences, such as the etiology of bruxism, the role of occlusion in Temporomandibular Disorders (TMD), orthodontic treatment, and its effects on TMD pain, and determining a correct mandibular position as a reference point for treatment [2]. When a dentist performs dental procedures like fillings, crowns, bridges, removable prosthesis, implant-supported restorations, full mouth reconstructions, orthodontics, occlusal therapy, tooth extraction, and so on, it may affect occlusion and bring some changes in occlusal force balance of the masticatory system of a patient.

The study of occlusion in dentistry has two components: the science and the art. Objective clinical issues like how teeth fit together, and how the forces or stresses generated within the masticatory system affect the teeth and supporting structures are addressed by the science component. However, the subjective response “feel” of the patient to their natural or therapeutic occlusion and its customized management by clinicians is more of an art than a science. Hence, the study of dental occlusion is always a mixture of science and art. With so many concepts and philosophies in clinical practice of occlusion, the question arises on how to choose the best occlusal scheme for the patient? Patients generally adapt to various occlusal schemes delivered by differing clinicians, which are based upon the clinician’s knowledge, occlusal skill, and comfort rendering the occlusal treatment. Hence, in the clinical practice of occlusion in minimally invasive comprehensive dentistry, a clinician must follow the knowledge of scientific literature and research-based evidence, and use his or her clinical experiences and artistic skills to respect the patient’s ability to physiologically adopt the new occlusal schemes.

Several reviews of the literature regarding the history of dental occlusion suggests that occlusion can be divided into three physiologic stages [36] and they are:

  • Normal occlusion and commonly known as “physiologic” occlusion, which suggests that treatment is not required.

  • Pathologic occlusion, also known as “non-physiologic,” which suggests that treatment may be required.

  • Therapeutic occlusion, often referred as to “treatment” or an “ideal” occlusion.

In clinical practice, there are three treatment categories routinely employed in occlusal treatment [2].

  1. 1.

    Occlusal Maintenance: This is the first category where the existing scheme of the occlusion is not changed, and only a limited number of restorations are introduced to a physiologically acceptable original occlusal scheme (Fig. 8.3).

     
  2. 2.

    Occlusal Modification: This is the second category where only minor or moderate changes or improvements are made to the original occlusal scheme but maintaining the original intercuspal position and vertical dimension of occlusion (VDO), that is either physiologically acceptable, or nonphysiologic and unacceptable (Fig. 8.4).

     
  3. 3.

    Occlusal Reconstruction: This is the third category where major occlusal scheme changes are made to improve a non-physiologic or unacceptable occlusion into physiologic occlusion by changing intercuspal position and/or establishment of new vertical dimension of occlusal (VDO) (Fig. 8.5).

     
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Fig. 8.3

(ab) Example of occlusal maintenance category: anterior direct composite veneers with existing occlusion maintenance

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Fig. 8.4

(ac) Example of occlusal modification but maintaining original vertical dimension of occlusion (VDO): orthodontics treatment followed by temporary restorations

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Fig. 8.5

(af) Example of occlusal reconstruction—non-prep restorations for dental occlusion reconstruction with VOD modification

Among three categories of occlusal treatment, the maintenance and modification types are considered easier to accomplish when compared to the reconstruction type, because the first two types are founded on preexisting intercuspal position (reference point) and the pretreatment vertical dimension of occlusion (VDO). However, when an occlusal treatment is required to convert pathologic occlusion into physiologic occlusion, then a new occlusal scheme needs to provide, requiring suitable changes on existing intercuspal position and/or vertical dimension.

At this stage, the original intercuspal position is no longer available for the clinician as the reference point. This is considered as a complex case in restorative dentistry and is one of the core clinical areas in the study of the art and science of occlusion where many clinicians may become confused as to how to address different clinical situations with the best occlusal Scheme.

A new reference point needs to be selected based on the newly determined mandibular positions, which further adds to the confusion, based on the Jaw Position Theories (Table 8.1).

Table 8.1

Jaw position theories

Centric relation theory (Schuyler): The occlusion is determined by the manner in which the ligaments brace the components of the jaw joint, particularly the rearmost hinge axis [56]. There are various clinical techniques proposed to record centric relation (CR). The bimanual manipulation technique of Dawson [4], the Lucia jig, and the leaf-gauge technique, as reported by Long [149], are popular techniques for positioning the mandible in CR. Prior to this, chin-point guidance and swallowing techniques were used to locate and record CR

Neuromuscular theory (Jankelson): The occlusion is determined by gravity and based on the position in which the jaw muscles are most relaxed. Trans electric nerve stimulation (TENS) is employed to relax the muscles [150]

Intercuspal theory: The occlusion is determined by the habitual fit with the most tooth contact

Anterior protrusive position theory (Gelb 4/7 position): The occlusion is determined by the manner in which the muscles brace the components of the jaw joint. The Gelb 4/7 jaw position is found by using appliances to open the occlusion and reposition the mandible forwards and downwards of the true center of the glenoid fossa [150]

The newly selected mandibular position (position of mandibular condyle within the glenoid fossa of the temporal bone) directly affects the occlusion because the condyles and the teeth each occupy the opposite ends of the solid mandible. Every clinical case is different as it is related to a patient’s status of health, their functional requirements, and their aesthetic needs and desires. Function is directly related to the forces that a patient generates within his/her stomatoganthic system.

There are four different theories that clinicians can view and think about occlusion. Each of these theories has its individual value, and treatments that are founded on each have been successful. These theories of occlusion differ in the consideration of where the jaw or temporomandibular joint should be positioned during the treatment. Despite their theoretical mandibular position differences, all of these theories have similar agreement on the following four concepts, which are related to occlusal contacts and occlusal forces [5, 79].

  1. 1.

    How teeth should meet during mandibular closure: All teeth should occlude simultaneously in mandibular closure movement.

     
  2. 2.

    How the occlusal load should be distributed within the dental arch: An equal percentage of occlusal forces should be shared between the right and left arch halves.

     
  3. 3.

    How the occlusal load should be distributed on tooth: An equal percentage of occlusal force should be distributed on each tooth’s cross-arch counterpart tooth.

     
  4. 4.

    Lateral excursive contacts: Anterior teeth should immediately disclude the posterior teeth during excursive movements.

     

Based on the laterotrusive movements from centric occlusion, various concepts of functional occlusion were recognized and advocated as physiologic: balanced occlusion [10, 11] canine-protected occlusion [1219], group function occlusion [2024], mixed canine-protected and group function [25], flat plane (attrition) teeth occlusion [26, 27], biologic (multi-varied), physiologic occlusion [28]. However, no single type of functional occlusion has been found to predominate in nature, and there appears to be no scientific evidence to support one occlusal scheme over other [29]. It is, therefore, when selecting a suitable mandibular position for the treatment, the clinician must consider the possible clinical effects that the selected mandibular position will have on the final occlusion outcome, and the extent of the treatment required, and its biological cost to achieve the treatment goals. Hence, the Vedic Smile Dentistry (VSD) protocol advises to choose the most conservative occlusal treatment approach to lessen both the biological and financial cost of the treatment for the patient.

8.3 Occlusal Forces: Key to Occlusal Harmony

Dental occlusion should be observed as the relationship between teeth, masticatory muscles, and temporomandibular joints in a function and dysfunction that generates craniomandibular forces and stresses within the stomatoganthic system of a patient. If a clinician can appreciate the study of dental occlusion as an art and science of craniomandibular force balance, then it is much easy to apply practically in clinical dentistry to achieve optional oral health through occlusal harmony. The stomatoganthic system is a complex unit, consists of an interactive network of teeth, their occlusion and supporting mechanisms, the upper and lower jaws, the temporomandibular (jaw) joints, the muscles, the blood and nerve supplies, and the salivary glands, designed to carry out three major functions: mastication, swallowing, and speech. These functions are basic to life, but are also secondary functions that support in respiration, and the expression of human emotion. Utilizing coordinated muscle contraction, mandibular motion and craniomandibular forces are generated, which is then closely involved with the functioning of the dentition. The geometry of craniofacial skeleton with muscles attached, all are related to the tooth compressions that occur when the mandible is in motion, which generates occlusal forces between the mandible and the cranium.

8.4 Mastication and Occlusal Forces

Mastication is the act of chewing food [30] and is a complex function that utilizes not only the masticatory muscles, the teeth, and the periodontal supportive structures, but also the lips, cheeks, tongue, and the salivary glands. Mastication is made up of rhythmic, and well-controlled separations and closures of the maxillary and mandibular teeth. Studies have shown that during an act of mastication, tooth contact does occur, where few contacts occur when the food is initially introduced into the mouth, but then as the bolus is broken down, the frequency of tooth contacts increases [31, 32]. However, in the final stage of mastication just before swallowing, tooth contact occurs during every stroke but forces to the teeth are deemed minimal [33]. The amount of the force placed on the teeth during mastication varies greatly from individual to individual and multiple other factors, as shown in (Table 8.2) [3439].

Table 8.2

Function and tooth contact forces [3437, 40]

Function

Occlusal force (kg)

Chewing

6.8–26.7

Swallowing

30.2

Maximum bite force

70–400

Parafunction

70–400

8.5 Swallowing and Occlusal Forces

The act of swallowing requires a series of coordinated muscular contractions that move a bolus of food from the oral cavity, through the esophagus, to the stomach and it consists of voluntary, involuntary, and reflex muscular activities. During swallowing, the teeth are brought up into their maximum intercuspal position (MIP), which well stabilizes the mandible by fixing its position against maxilla, so that contraction of the suprahyoid and infrahyoid muscles can control the hyoid bone during swallowing. There are two types of swallowing: somatic (adult) and visceral (infantile). In adult swallowing, the teeth are used to stabilize the mandible, but during infantile swallowing, the mandible is braced when the tongue is placed forward and between the dental arches or gum pads [40]. This type of swallowing remains with the child until the posterior teeth erupt. The occlusal forces produced during swallowing in asymptomatic adults are shown in (Table 8.2).

8.6 Speech and Occlusal Forces

Speech is the third major function of the stomatoganthic system. Controlled contraction and relaxation of the vocal cords and the bands of the larynx create sounds with the desired pitch. By varying the relationships of the lips and tongue to the palate and teeth, a human can produce a variety of sounds [41]. However, tooth contacts do not routinely occur during speech, such that no tooth contact force is generated during any act of speech.

8.7 Parafunctional and Occlusal Forces

As mentioned above mastication, swallowing, speaking, respiration, and expressing emotional expression are the vital functions of the stomatoganthic system. However, some activities are considered “nonfunctional” or parafunctional, and are popularly known as self-destructive oral habits. The following are the so-called parafunctional habits:

  • Teeth clenching for long duration.

  • Teeth grinding at night time as seen in bruxism.

  • Sustained contractions of the muscles of mastication (without dental contact).

  • Chewing of the lips, cheeks, or tongue.

  • Tongue thrust.

  • Nail chewing, cuticle chewing.

  • Chewing foreign objects (e.g., pencil).

  • Patient self-altering of their mandibular posture.

All these parafunctional habits produce some type of forces within the stomatoganthic system. However, their harmful effects depend upon the magnitude, direction, duration, and the frequency of the force applied to the system. Among these commonly observed oral parafunctional habits, bruxism and clenching are more important as they produce heavy occlusal forces within the stomatoganthic system, and these activities can occur subconsciously and the patients are often unaware about their active parafunction. In Vedic Smile Dentistry (VSD) protocol, the clinician must rule out and consider parafunctional activities such as bruxism and clenching during diagnosis, treatment planning, and execution. The occlusal forces comparison between functional and parafunctional activities (bruxism and clenching) is shown in Table 8.2.

8.8 Occlusal Force Harmony, Disharmony, and Disorders

When a person uses their stomatoganthic system for the above-mentioned activities and habits, masticatory forces generated are often disseminated through a series of complex physiological processes within the body. The physiological tolerance level (the resistive and adaptive capacities) of the patient plays a vital role in maintaining occlusal force harmony. If the ongoing disharmony of the occlusal forces exceed the physiologic tolerance limit of the patient, the system can breakdown, which usually begins with the “weakest link” like teeth, muscles, joints, or airway (TMJA complex) within the individual’s stomatoganthic system, creating sign and symptoms of occlusal force disorder (Fig. 8.6). Hence, Occlusal Force Disorders (OFD) can be defined as “the disorders of teeth, muscles, temporomandibular joints, and airway (TMJA-Complex), resultant from excess occlusal force which is greater than the individual’s adaptive capacity” [2]. There are four major occlusal force disharmony factors that directly or indirectly affect the force components of the masticatory system [2].

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Fig. 8.6

(aj) Some examples of Occlusal Force Disorders (Image Courtesy Vedic Smile, Nepal). (a) Severe attrition due to heavy bruxism. (b) Cheek marks (linea alba) resultant from heavy teeth clenching. (c) Tongue indentation of a person with heavy clenching habit. (d) Exostoses formed from heavy occlusal forces. (e) Cervical abfraction due to significant frictional forces on excursive movement. (f) Cervical abfraction on anterior teeth due to deep bite and heavy forces. (g) Loss of canine guidance and anterior teeth attrition. (h) Fracture of the ceramic layer of a PFM crown, due to a concentrate of heavy occlusal force on the restoration. (i) Fracture tooth cusp due to high excursive movement frictional forces. (j) Panoramic radiograph showing heavy bruxism. Note the flat cusps and minimal enamel present on the posterior teeth. (k) Panoramic radiograph showing prominent mandibular angles due to hyperactive masseter muscles

Morphological Factors:

  • Dental type: Intercuspal position (ICP) contacts, the angle of tooth contacts, the type of tooth contacts presents in an excursive movement, the anterior-posterior contact location.

  • Condylar position: The relation of mandibular condyles with the glenoid fossae.

  • Craniofacial type: Dolichofacial, mesiofacial, or brachyfacial type affect the vertical dimension of occlusion (VDO) and directly affect the generation of occlusal force magnitude.

Pathophysiological Factors: Tooth decay and periodontal diseases affect occlusal force balance due to the loss of tooth contact surface, periodontal supporting tissues, and the tooth itself. Pathological conditions like upper airway obstruction may lead to the various malocclusion, oral breathing, and sleep breathing disorders. Sleep breathing disorders can promote parafunctional habits like teeth clenching and grinding, which produce high occlusal force within the stomatoganthic system.

Parafunctional Habit and Psychosocial Factors: Parafunctional habits such as bruxism and teeth clenching are thought to be closely related to various psychosocial factors like anxiety, depression, stress, emotional sensitivity, hyperactivity, and personality type. These habits generate high occlusal forces within masticatory systems, leading to occlusal force disorders (OFD). However, in clinical dentistry, the management of these parafunctional habits is the most neglected, thereby affecting the long-term success of restorative dentistry.

In Vedic Smile Dentistry (VSD) practice, the early recognition, correct diagnosis, and suitable intervention of occlusal force diseases is given a high priority. Hence, a detailed clinical history, thorough clinical examination, and suitable diagnostic tests are recommended to recognize the “weakest link” (the teeth-periodontium, muscles, mandible and joints, and airway complex) within the patient’s stomatoganthic system to develop a suitable treatment plan for long-term health, function, and aesthetics at minimal biological cost. The sign and symptoms of OFD [2] are classified into four clinical categories as shown in Table 8.3 for better understanding. It should be noted that the sign and symptoms of the differing occlusal force disorder types are not mutually exclusive but are interrelated [2].

Table 8.3

Clinical sign and symptoms of occlusal force disorders (OFD) [2]

 

Teeth and periodontal complex

Type 1

Teeth: Excessive tooth wear (attrition), abfraction formation, tooth fracture, enamel cracking, tooth mobility, frequent restoration failure, implant prosthesis loosening, dentinal hypersensitivity, pulpitis, pulpal atrophy, pulpal dystrophic calcification, and tooth pain upon occluding

 

Periodontium: Tooth hypermobility, gingival recession, thickening of the lamina dura, tooth migration

 

Alveolar bone: Angular bone loss, the presence of tori and exostosis, and dehiscence

Type II

Muscles complex

 

Masticatory muscles: Tender to palpation, masticatory muscle hypertrophy, muscle in coordination, muscle fatigue, muscle hyperactivity, pain, discomfort, and reduced range of mandibular motion, temporal headache, and earache

 

Lips, cheek, and tongue: Cheek mark (linea alba), traumatic ulcers, tongue indentation

Type III

Mandible and joint complex

 

Mandible and TM joint: Movement deviation, internal disk derangement, clicking sounds, structural deformation, maxilla-mandibular TM joint asymmetry, TM joint discomfort and pain, TM joint degenerative changes, and locking and dislocation

Type IV

Airway complex

 

Upper airway obstruction and breathing mode: The main characteristics of a compromised airway complex (upper airway obstructions and breathing mode) are the presence of hypertrophied tonsils or adenoids, mouth breathing, anterior open occlusion, cross bite, excessive anterior facial height, incompetent lip posture, excessive appearance of maxillary anterior teeth, narrow external nares, and a V-shaped maxillary arch

8.9 Dental Occlusion Analysis: The Digital Vs Nondigital Approach

A primary principle of comprehensive dentistry is that all of the components of the masticatory system (teeth, soft tissues, skeletal structures, occlusal force disharmony, muscles, and joints) are intimately related and dependent on one another for ideal function [42, 43], and address both function and esthetics [4446]. The Vedic Smile Dentistry (VSD) practice follows the psychology, health, function, and aesthetics as orders of the treatment steps while approaching any clinical cases in dentistry. Therefore, some typical examples of dental disturbances linked to dental occlusion can be bruxism, attrition, erosion, abfraction, muscle pain dysfunction syndrome, and TMJ problems [4755].

Occlusal concepts are developed together with advances in the dental technology enabling improved restorative options. Fully balanced occlusion is required for complete dentures and was initially used with fixed restorations for a short time. This was abandoned in favor of “mutual protection,” “anterior guidance,” and “anterior disclusion.” However, current concepts create a paradigm shift from “mutual protection” with “anterior disclusion” to a “selective excursive guidance” with “selective disclusion” guided by “individual clinical determinates” [10, 22, 5658, 59]. Decisions for patient-driven therapy will need to consider the best therapeutic options for the particular patient, their quality of life, comfort, age, and health, psychophysiological, and psychosocial conditions. Excessively rigid concepts need to be avoided and decisions tailored to patient-centered needs and expectations [60]. Comprehensive dental occlusion analysis has four key areas in clinical examination and documentation: teeth fit, muscles coordination, joints stability and airway pattern, also known as the TMJA components.

  • Airway Pattern: The dysfunction of human airway and breathing pattern can cause malocclusion and skeletal deformation [6166].

  • Joints Stability: The morphology and relation of temporomandibular joints position with glenoid fosse guides the joints stability, its movements in coordination with muscles and neurons.

  • Muscles Coordination: The masticatory muscles in coordination with the neural system controls the application of force or load (magnitude, duration, and direction) over the teeth and joints.

  • Teeth Stability: The number of teeth, position, and their morphology guides the maximal intercuspal position (ICP) of teeth stability (occlusal stability).

Priority is given to examining the joint stability to recognize the level of occlusal instability. The information on existing joints and occlusal stability quality is very important in establishing a correct diagnosis and suitable treatment plan. Hence, during dental occlusal analysis, it is necessary to find out the patient’s true occlusion relation (CR) with joints, as occlusal contacts on a small number of teeth create discomfort, causing the patient to subconsciously shift the jaw to a habitual bite (Centric Occlusion) position where the upper and lower teeth are in maximum intercuspation. This subconscious mechanism is called the “Neuromuscular Avoidance Pattern” [67]. This mechanism prevents clinicians from seeing CO-CR discrepancies in the mouth at the time of the initial examination [6871] and makes the clinician to believe that it is the patient’s true occlusion relationship.

Various scientific studies have already proven that occlusal instability (malfunction) causes deflective temporomandibular joints (TMJ) positioning [71], which can lead to the development of tissue damage, such as the loosening of the ligamentous apparatus [72], inflammation of the capsular components, displacement of the condyle and articular cartilage [73], or in the worst case, resorption of the bony structures of the TMJs [74]. These kinds of tissue injuries can lead to symptoms such as muscle hyperactivity, neck pain, headaches, and other neurological symptoms such as muscle or joint pain and/or decreased range of motion of the mandibular movements in a very high percentage of cases [7584]. Hence, dental occlusion seems to be a “fine-tuning” neurologic feedback system that guides mandibular movements against maxillary dentition [8588]. At the same time, occlusal contacts (occlusal stability) seem to be responsible for maintaining the condylar position within a physiological range [8992]. The extent of the dental occlusion examination will vary from patient to patient.

In Vedic Smile Dentistry (VSD) approach, a comprehensive occlusal examination (TMJA Complex Analysis) is advisable when a patient present with complex problems requires a planning of major restorative works with the change in the existing occlusal scheme and vertical dimension of occlusion. The comprehensive occlusal examination process begins with careful history taking and meticulous clinical examination. All sign and symptoms of OFD should be recorded, and any necessary investigations such as articulated study casts, vitality test, dental radiograph, and imaging (CBCT, MRI) and sleep analysis test may be prescribed for additional information. The patient’s existing occlusal indicators should be documented as well as this assists in case monitoring and follow-up.

The chapter has introduced the concept of occlusion and its importance in diagnosis till now. The next segment of the chapter deals with performing occlusal analysis using digital and nondigital approach.

8.10 The Nondigital Approach in Occlusion Analysis

  1. 1.

    In nondigital approach, the status of existing static and dynamic dental occlusion is examined via different static dental materials such as articulating paper strips, shimstock foils, elastomeric impression materials; occlusal wax sheets are placed between opposing teeth to imprint, or mark with color, the occlusal contacts. These nondigital occlusal indicators are often combined with the patient’s verbal feedback based on proprioception occlusal “feel,” to guide a clinician in detecting heavy occlusal contact points. It is interesting to note that articulating paper mark size is widely used and accepted as an indicator of forceful tooth contact. This has been advocated in textbooks on occlusion [53, 9396] as the paper mark area being representative of the occlusal load. The darker paper marks (“bull’s-eye”) indicate heavy load or excessive forces, and smaller lighter marks indicate lesser loads [53, 93, 94]. Additionally, the presence of many similar-sized paper marks spread around the contacting arches are indicative of equal occlusal contact intensity, and evenness, and simultaneity [96, 97].

     

However, recent studies have shown that markings seen on the teeth do not quantify occlusal forces or time sequence of the occlusal contact order, and that the ink substrate left on the teeth is not an accurate indicator with which to judge a tooth contact’s relative force levels [52, 98100]. To date, the literature offers no evidence to suggest that variable articulation paper mark shape and size can describe varying occlusal contact forces in any predictable way [52, 98102]. Articulators may be the most useful tools for the production of dental restorations, but they cannot simulate the neuromuscular mechanism [103].

In summary, occlusal indicators such as articulating paper strips, shimstock foils, elastomeric impression materials, occlusal wax sheets marks specifically only indicate occlusal contact location and contact size, not occlusal force levels and contact timing durations [52, 98]. In addition, although, they print of the end of the occlusion, they cannot provide significant information such as which tooth is the first one in occlusion, which one is second, or which one is the last, and the force differences between these contact points. Hence, in contemporary clinical practice, reliability on only on a manual approach to occlusion analysis is questionable.

8.11 The Digital Approach to Occlusion Analysis

Digital occlusal analysis systems are the fastest and safest way to analyze the dental occlusion. If not intervened, all occlusal contacts can be controlled in detail and tied in sequentially together with relative force information. Analysis of the occlusion can be performed under maximum physiological conditions. Each intervention will be perceived by the neuromuscular mechanism, and the movement will not be a physiological function.

Digital occlusal analysis systems give the clinician control of extreme physiologic occlusion [104109]. Digital Occlusion, started with the use of first T-Scan I system in 1984 (T-Scan 200, Tekscan, Inc., Boston, MA, USA). The earliest publication about T-Scan I system appeared in the dental literature in 1987 [110]. The development of this technology has required many iterations over the past decades beginning with T-Scan I, T-Scan II for Windows®, T-Scan III with turbo recording, to a simplified desktop version introduced in T-Scan 8, to the present-day version known as T-Scan 10 (Fig. 8.7).

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Fig. 8.7

(a, b) The T-Scan 10 recording hardware components include the Novus recording handle, two sizes of plastic molded sensor supports and two sizes of the High Definition (HD) Novus-specific sensors (Photos Courtesy of Tekscan™, Inc.)

Since mid-1985, numerous authors have studied the various T-Scan versions and have clinically validated the T-Scan sensor’s occlusal force reproduction and its timing quantification in literatures [111120], which inspired the manufacturer to improve the hardware components and the system’s recording sensors, to be more accurate, repeatable, and precise. A reliable recording methodology and definitive treatment protocols have been developed and tested in research environments [2, 121132]. With the popularity of digital occlusion concept in dental medicine, now there is a high demand for simple and cost-effective, yet predictable digital occlusion product in the global market. This led to the development of a new digital occlusion product in 2019, OccluSense® by Bausch GmbH & Co. KG (Fig. 8.8).

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Fig. 8.8

The Occlusense recording handle and an unused recording sensor (Image Courtesy by Bausch GmbH & Co. KG, Germany)

The new system developed by Bausch combines the traditional tooth marking and digital registration of the pressure distribution on occlusal surfaces together. The device is being used in combination with a 60 microns thin single-use pressure sensor color coated in red, which is applied exactly like a conventional occlusion test foil. The patient masticatory pressure distribution is recorded digitally in 256 pressure levels and later transmitted to the OccluSense application software for further evaluation. The recordings are being stored in the patient management system of the application software and can be reviewed or exported at any time. The company has marketed the device as electronic articulating paper.

However, the author prefers to categorize it as digital articulating paper as the device can provide tooth contact location with red ink mark on the tooth and with relative pressure. Furthermore, there is no need to use another set of conventional articulating paper to correlate the digital tooth contacts location. The author believes that, due to its ability to provide only two basic occlusion information, that is, tooth contact location and tooth contact relative pressure, it could be very useful for day-to-day simple to moderate cases of checking teeth contact location and their relative pressure. OccluScense system is a relatively new invention with not much research or evidence base to its credit.

For complex occlusal treatment cases, a clinician may need to gather all fundamental occlusal information during diagnosis, treatment, and follow-up to maintain, modify, or reconstruct new occlusal scheme to enhance the occlusal harmony. T-Scan system is capable of providing the clinician all such occlusal information if required. With more than three-decades-long history, the T-Scan system’s has progressed incredibly, with rigorous testing, criticisms, and improvements of its different versions [60, 113, 114, 133142]. The current version that is available in the market, T-Scan 10, can record 256 levels of relative occlusal force presented in a multiple spectrum of colors, while simultaneously registering the time sequence of occlusal contacts in 0.003 s increments.

Practicing digital occlusion by using precise objective data to isolate problem occlusal contacts is very different from practicing subjective interpretation, which uses ink marking materials and subjectivity to isolate occlusal contacts. For ease to understand the clinical capabilities of both digital occlusal-related devices presently available in the market, and to select them as per clinical requirement in the practice, a simple comparison between conventional articulating paper, digital articulating paper (OccluSense), and digital occlusion scanner (T-Scan 10) is shown in Table. 8.4.

Table 8.4

Comparison between conventional articulating paper, digital articulating paper (OccluSense), and digital occlusion scanner (T-Scan 10)

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Aug 7, 2022 | Posted by in General Dentistry | Comments Off on Occlusal Analysis and Force Finishing

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