Condylar Guidance In Articulator and Bilateral Balanced Occlusion

Condylar Guidance In Articulator and Bilateral Balanced Occlusion

Given condylar and incisal guidance in the articulator, what are other factors in considering balanced occlusion? Give a note on each factor.
Balanced Occlusion

• Balanced occlusion is the simultaneous contacting of the maxillary and mandibular teeth on the right and left and in the anterior and posterior occlusal areas when the jaws are in either centric or eccentric relation.
• Balanced sliding occlusion is the even contacting of teeth as the mandible moves to and from eccentric and centric maxillomandibular relations.
• Balanced occlusion is associated with cusp from posterior teeth and unbalanced occlusion is with noncusp from posterior teeth.

Read And Learn More: Complete Dentures Question and Answers

Advantages of Bilateral Balanced Occlusion

Enables the denture to be seated during activities such as swallowing saliva, and closing to reseat the dentures. If teeth are not arranged in balanced occlusion, the constant unseating of the denture bases creates soreness and inflammation, which may lead to accelerated bone resorption. The denture is compromised in stability, retention, and comfort.

Factors Affecting Occlusal Balance (Hanau’s Quint)

• Condylar guidance
• Incisal guidance
• Plane of occlusion
• Compensating curve
• Angulation of the teeth / Cuspal height.

Balanced Occlusion 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.

Balanced Occlusion Incisal Guidance

• It is defined as, “The influence of the contacting surfaces of the mandibular and maxillary anterior teeth during mandibular movements.” —GPT
• Incisal guidance is the effect of contact of the upper and lower anterior teeth 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.

Balanced Occlusion 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.

Balanced Occlusion 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

Balanced Occlusion Types of Compensating Curves

• Anteroposterior curves
• Lateral curves.

Balanced Occlusion The curve of Spee is defined as, “Anatomic curvature of the occlusal alignment of teeth beginning at the tip of the lower canine and following the buccal cusps of the natural premolars and molars, continuing to the anterior border of the ramus as described by Graf Von Spee.” —GPT.

It is an imaginary curve joining the buccal cusps of the mandibular posterior teeth starting from the canine and passing through the head of the condyle.

Balanced Occlusion Significance: In protrusion, the posterior teeth arranged to incorporate this curve will remain in contact without disocclusion.

Balanced Occlusion Lateral Compensatory Curves

• This curve runs across the palatal and buccal cusps of the maxillary molars. During lateral movement, the mandibular lingual cusps on the working side should slide along the inner inclines of the maxillary buccal cusp.
• On the balancing side, the mandibular buccal cusps should contact the inner inclines of the maxillary palatal cusp. This relationship forms a lateral balance It is determined by the inclination of the posterior teeth and their vertical relationship to the occlusal plane so that the occlusal surface results in a curve that is in harmony with the movement of the mandible as guided posteriorly by the condylar path.
• A steep condylar path requires a steep compensating curve for occlusal balance.
• A lesser compensating curve for the same condylar guidance would result in a steeper incisal guidance (anterior interference), which would cause a loss of molar balancing contacts.

Balanced Occlusion 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.

Balanced Occlusion Factors Affecting Protrusive Balance

1. Condylar inclination represents the path of the condyle in protrusion modified by the combined action of all of the tissues of the temporomandibular joint and the ridges covered by the recording bases.
2. The inclination of the incisal guidance is chosen for the patient
3. The inclination of the plane of occlusion is set to physiologic factors.
4. The compensating curve is set to harmonize with 1 and 2.
5. Cusp heights and tooth inclination of the posterior teeth can be adjusted depending on other factors.

Balanced Occlusion Factors Affecting Lateral Balance

1. The inclination of the condylar path on the balancing side.
2. The inclination of the incisal guidance and cuspid end-to-end contact.
3. The inclination of the plane of occlusion on the balancing side and working side.
4. The compensating curve on the balancing side and working side.
5. The buccal cusp heights or inclination of the teeth on the balancing side.
6. The lingual cusp heights or inclination on the working side.
7. The Bennett side shifts on the working side.
8. The forces of occlusion should be balanced from right to left and anterior to posterior in complete dentures.