Hanau’s Quint Short Notes

Hanau’s quint (Rudolph L. Hanau).

He proposed nine factors that govern the articulation of artificial teeth:

1. Horizontal condylar inclination
2. Compensating curve
3. Incisal guidance
4. Plane of orientation
5. Inclination of tooth
6. Sagittal condylar pathway
7. Sagittal incisal guidance
8. Tooth alignment
9. Relative cusp height.
   These nine factors were called the laws of balanced articulation.
   Later he condensed these nine factors and named five factors, known as Hanau’s Quint:
   1. Condylar guidance
   2. Incisal guidance
   3. Compensating curves
   4. Relative cusp height
   5. Plane of the orientation of the occlusal plane.

Hanau’s Quint Modifications of Hanau’s Quint

Hanau’s quint Trapozzano’s Triad of Occlusion

His triad of occlusion included:

• Condylar guidance,
• Incisal guidance
• Cusp height.

He eliminated the plane of occlusion as he considered that factor as a variant depending on the interarch distance. He also dismissed the need for setting compensating curves, as these curves are dependent on the cuspal inclination and not an individual factor.

Hanau’s Quint Boucher’S Concept Gave Importance To:

• Orientation of the occlusal plane
• The incisal guidance
• Condylar guidance
• Angulation of the cusp
• Compensating curve.

Boucher compensating curve permits alteration of cusp height without changing the form of teeth. In zero-degree teeth, the equivalence of a cusp can be produced by a compensating curve. Others who modified Hanau’s Quint were Lott and Levin.

Hanau’s Quint Factors Influencing Balanced Occlusion

The five basic factors that determine the balance of an occlusion are:

1. The inclination of the condylar path or condylar guidance.
2. Incisal guidance.
3. Orientation of the plane of occlusion or occlusal plane.
4. Cuspal angulation.
5. Compensating curves.

Hanau’s Quint Condylar Guidance

• Condylar guidance can be defined as, “Mandibular guidance generated by the condyle and articular disc traversing the contour of the glenoid fossa.”—GPT
• The condylar path should be determined on the patient and set on the instrument so that the patient’s temporomandibular joint is in harmony with the occlusion as programmed on the articulator.
• A steep condylar path needs a steep compensating curve for occlusal balance. If a lesser compensating curve is substituted for a steep condylar guidance it would result in a steep incisal guidance resulting in loss of molar balancing contacts.

Hanau’s Quint Incisal Guidance

• It is defined as, “The influence of the contacting surfaces of the mandibular and maxillary anterior
  teeth during mandibular movements.” –GPT It is the effect the contact of the upper and lower anterior teeth have on the movement of the mandible.
• It is usually expressed in degrees of angulation from the horizontal by a line drawn in the sagittal plane between the incisal edges of the upper and lower incisor teeth when closed in centric occlusion.
• If the incisal guidance is steep, it requires steep cusps, a steep occlusal plane, or a steep compensating curve to effect an occlusal balance. A steep inclined plane is detrimental to the stability and equilibrium of the denture base hence for complete dentures the incisal guidance should be as flat as esthetics and phonetics will permit.
• When the arrangement of the anterior teeth necessitates a vertical overlap, a compensating horizontal overlap should be set to prevent dominant incisal guidance (anterior interference) from upsetting the occlusal balance on the posterior teeth.

Hanau’s quint Plane of Occlusion

• It is defined as, “An imaginary surface which is related anatomically to the cranium and which theoretically touches the incisal edges of the incisors and the tips of the occluding surfaces of the posterior teeth. It is not a plane in the true sense of the word but represents the mean curvature of the surface.” –GPT
• It is established in the anterior by the height of the lower cuspid and in the posterior by the height of the retromolar pad. It is also related to the ala-tragus line, or Camper’s line. Its position can be altered only slightly without creating serious functional problems.

Hanau’s Quint Compensating Curve

Compensating curve is defined as, “The anteroposterior and lateral curvatures in the alignment of the occluding surfaces and incisal edges of artificial teeth which are used to develop balanced occlusion.” –GPT

Hanau’s Quint Types Of Compensating Curves

• Anteroposterior curves
• Lateral curves.

Hanau’s Quint Cusps On Teeth Or The Inclination Of Cuspless Teeth

• Cusp angle is defined as “The angle made by the average slope of a cusp with the cusp plane measured mesiodistally or buccolingually.”–GPT
• The mesiodistal cusp heights that inter-digitate lock the occlusion so that repositioning of the teeth due to settling of the base cannot take place.
• To prevent this problem, it is advocated that all mesiodistal cusp heights be eliminated, hence only the buccolingual inclines are considered determinants of balanced occlusion in anatomic-type teeth.
• Once the vertical and horizontal overlaps of the anterior teeth have been established incisal guidance, the plane of occlusion, the compensating curve, and the tooth form must harmonize with the three guiding elements if balanced occlusion is to be achieved on the articulator.
• The incisal guidance and the plane of occlusion can be altered only a slight amount because of esthetic and physiologic factors. The compensating curve and the cuspal inclinations can be adjusted by the dentist.