As described by Hanau, they seem very confusing and unnecessarily complicated. Hanau was not a dentist, but an engineer and a great researcher. He believed articulation of artificial teeth was related to 9 factors. Compensating curve Protrusive incisal guidance Plane of orientation Bucco-lingual inclination of tooth axes Sagittal condylar pathway Sagittal incisal guidance Tooth alignment Relative cusp height He mathematically charted 9 factors and listed the laws of balanced articulation in a series of 44 statements. Condylar guidance Compensating curve Relative cusp height Incisal guidance and Plane of orientation.
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This article describes a formula that is introduced to quantify a balanced occlusion within the context of the Hanau quint and discusses the limitations of the formula due to individual variabilities of mandibular movements. You must be signed in to read the rest of this article. Balanced occlusion has been proposed to promote the stability and retention of complete dentures.
This dynamic functionality of denture occlusion has been described as the interrelationship of five factors, the so-called Hanau quint, named for researcher Rudolph L. For esthetics, the vertical overlap is increased to display the incisors and mimic the relation of natural dentition.
The increased IG, however, may alter the masticatory muscle activities and restrict the functional range of mandibular movements. An ideal OP may display a relatively flat and parallel surface to the ridge of an edentulous arch. The posterior teeth disclude from occlusion demonstrating an interocclusal gap between maxillary and mandibular teeth and creating the so-called "Christensen phenomenon.
Nonanatomic teeth do not display a distinct cuspal morphology; anatomic teeth present a higher CI. This article describes a formula introduced to quantify a balanced occlusion within the context of the Hanau quint and discusses the limitations of the formula that are due to individual variabilities of mandibular movements.
Articulation in Centric Relation The maxillary and mandibular teeth are arranged to support the lower facial height and match with the centric relation of the condyle.
This position is reproducible and recordable, and is well received as a treatment position for the fabrication of complete dentures. The posterior teeth are arranged to provide centric stops to keep the occlusal vertical dimension and direct the occlusal forces in vertical direction. Anatomically, teeth demonstrate a distinct cuspal morphology for the establishment of cusp-to-fossa relations.
Because of close proximity to the transverse horizontal axis, the posterior teeth can display a greater degree of occlusal error.
The anterior teeth are influenced far less than the posterior teeth when the arbitrary location displays a discrepancy from the true axis of rotation. When mounted on an articulator displaying a short condylar axis, the arc of closure of the mandibular cast will be more acute than the arc of mandibular closure.
A deflective occlusal contact can occur on the CI of posterior teeth, demonstrating an open bite in the anterior region. The centric relation of the mandible may be an area rather than a point. The area of centric is described as either "long centric" or "freedom in centric. According to Suit et al, the lateral slide can range up to 1 mm. No interocclusal gap is observed when the OP is flat and parallel to the Frankfort horizontal plane.
According to a previous study, the average CG of edentulous patients is 36 degrees with a range of 10 degrees to 62 degrees. A symmetric CG was found only in Posterior disclusion may not occur when the OP is inclined or incorporates a CC to raise the occlusal surface of posterior teeth Figure 4 and Figure 5. The balance is maintained with the angulation of the posterior teeth as described as the inclination of OP, CC, CI, or a combination of these.
The articulator should be equipped with adjustable condylar elements to program the CG. The right and left condylar elements should be independent from each other to match with the asymmetric condylar pathways as reported in a previous study.
The graphic method will indicate the entire pathway of the condylar movement and can produce the curvilinear pattern of CG. The condylar pathway is not altered by the interincisal relations of anterior teeth. However, mandibular movement is influenced by the altered IG. According to this formula, the location of the tooth d is significant in producing the angulation of CI. The more anterior the tooth, the smaller is thevalue of d. Articulation in Lateral Excursion The working condyle rotates along the vertical axis of the condyle, while the balancing condyle is pulled down the articular eminence.
However, posterior disclusion occurs on the balancing side because of the downward movement of the balancing condyle. An incline should be developed to maintain the balance by matching the asymmetric cross-arch rotational movement of the mandible Figure 7 through Figure The incline is increased when the interincisal relation becomes more acute.
However, the increase of the working incline is not directly proportional to the increase of the IG because of the individual rotational movements of the working condyle. The vertical axis of the condyle is displaced in the lateral direction with anterior, posterior, superior, or inferior movements, or a combination of these. Although controversial, the working condyle cannot translate in a lateral direction unless the IT does not occur on the balancing side of the condyle. The bodily translation of the mandible is called Bennett movement,24 and Bennett angle is formed as the balancing condyle progresses further to continue the circular motion against the medial wall of the articular eminence.
The arc of a circle becomes more acute when the radius of the circle is decreased. However, the lateral translation of the mandible displaces the center of rotation located in the working condyle and consequently alters the positional relation of the balancing condyle causing an effect of a decrease in the intercondylar distance as a reference to the original center of the rotation.
In fact, the gothic arch tracing made by a graphic record is more lateral when combined with a smaller intercondylar distance. The working condylar ball remains in the condylar slot but the intercondylar pin slides laterally through the ball.
The challenge for clinicians is determining the location and inclination of the teeth located between the posterior determinant of CG and the anterior determinant of IG. For example, degree CI can be produced when a degree cusp tooth is combined by degree orientation of OP and degree CC. The more anterior the location of the tooth, the greater is the influence of IG. Thus, premolars will display a greater inclination than molars when IG is more acute than CG.
It indicates a relative location of a tooth from IG as reference to the two end-controlling factors. Alternatively, the dcan be quantified when the CI is determined in a complete denture demonstrating a balanced occlusion.
According to Christensen, the average value of d can be approximated as follows: 0. A curve can be incorporated into the OP to have an effect of inclination. This method, which is conceived based on anthromorphometric observation, is useful for designing a curved OP for balance. However, the optimal degree of CC is yet to be determined for balanced occlusion. A cuspal morphology may rise above the OP to fill the interocclusal gap created by the posterior disclusion.
According to Christensen, a cusp may demonstrate a height to compensate for the insufficient inclination of OP. The CI describes the angulation of posterior teeth, and cusp height determines the range of tooth contact occurring during excursive movements of the mandible. The taller the height of a cusp, the greater is the range of the balance. However, the functional range of mandibular movements rarely reaches the scope of the border movements.
The teeth are usually arranged to display a curve in the mediolateral direction. This mediolateral CC usually involves a more apical setting of lingual cusps than buccal cusps in the mandible. When the relative heights of those cusps are inverted, a reverse CC is produced. In essence, the CC is set to raise the balancing inclination and lower the working inclination.
Interestingly, the working incline is decreased as a function of increasing the balancing incline Figure 7. This approach enables a sphere to cross the OP in a lateral direction as indicated by the CI of posterior teeth. Semiadjustable articulators have limitations in reproducing the CG. The widely used Hanau H2 articulator is incapable of distinguishing the so-called "Fischer angle," ie, the difference between the horizontal CG and the lateral CG.
However, the occlusal error resulting from the incapacity of accepting the Fischer angle may not be clinically significant. These articulators are not designed to adjust the intercondylar distance and individual motions of working condyle. According to Weinberg, occlusal error can be significant when errors are cumulative. The maxillary cast should be mounted by means of a facebow record, although the arbitrary transverse horizontal axis may not be located within a 5-mm zone from the true transverse horizontal axis.
The cuspal morphology should not restrict the masticatory cycle of mandibular movement. When a balancing interference is noted, the maxillary palatal cusp is chosen as a centric stop to embrace the concept of lingual contact occlusion. This formula was found to approximate the protrusive incline when the distance of a tooth in question was determined as a reference to IG and CG.
However, when quantifying working and balancing inclines, the individual variabilities of condylar pathways and limitations of articulators commonly used to fabricate complete dentures should be considered. An occlusal error may occur requiring an intraoral adjustment. The centric relation of the mandible is critical as a starting point of balancing the occlusion.
The occlusal adjustment should encompass the basic principles of complete denture design, including a freedom in centric relation of the mandible and maintenance of the occlusal vertical dimension. Mack PJ. Aust Dent J. Christensen FT. Cusp angulation for complete dentures. J Prosthet Dent. The effect of incisal guidance on cusp angulation in prosthetic occlusion. Study of the sagittal condylar path in edentulous patients.
Comparison of condylar guidance setting obtained from a wax record versus an extraoral tracing: a pilot study. Hue O. The sagittal condylar paths in edentulous patients: analysis with computerized axiography. Int J Prosthodont. The influence of anterior guidance and condylar guidance on mandibular protrusive movement. J Oral Rehabil. Influence of different condylar and incisal guidance ratios to the activity of anterior and posterior temporal muscle.
Arch Oral Biol. A study of the occlusal plane orientation by intra-oral method retromolar pad. The commissure line of the mouth for orienting the occlusal plane. Engelmeier RL. The development of nonanatomic denture occlusion: Part IV.
Hanau Quint Described as a Formula to Quantify Balanced Occlusion
Name[ edit ] The name is derived from "Hagenowe", which is a composition of Haag wood and Aue open land by the side of a river. History[ edit ] Relic of the first medieval town-fortification Hanau in around Formerly it was the site of a castle which used the waters of the river Kinzig as a defense. The castle belonged to a noble family, calling themselves "of Hanau" since the 13th century.