Orthodontics Quiz on Anchorage Control and Occlusion

MBT Bracket System Overview

• Developed by Richard P. McLaughlin, John C. Bennett, and Hugo J. Trevisi
• Based on measurements from 120 non-orthodontic normal cases.
• Initial design focused on flexibility in bracket range and arch forms.
• Brackets centered on the clinical crown
• Focus on heavy force levels
• Later generations emphasized pre-adjusted appliances, standard SWA bracket selection, ovoid archwires, and light force levels and sliding mechanics.

Occlusion

• Occlusion in dentistry refers to the contact between the maxillary (upper) and mandibular (lower) teeth during chewing or at rest.
• It's a key concept in orthodontic treatment planning.

Orthodontics

• Orthodontics manages and treats malocclusion.
• Malocclusion, in most cases, isn't a disease but a variation from the ideal occlusion.

Ideal Occlusion

• Defined by static (morphological) and functional aspects.
• Lawrence Andrews described an ideal static occlusion using six keys, including updated molar relationships.

Keys to Ideal Static Occlusion

• Molar relationship: The proper positioning of molars, a key element in a correct bite.
• Crown angulation: The angle of tooth crowns, ensuring proper alignment.
• Crown inclination: Indicates the inclination of the crown relative to its axis, crucial for proper occlusion.
• No Rotation: Absence of tooth rotation prevents a misaligned bite, aiding proper function and appearance.
• No Spacing: Proper tooth-to-tooth contact, avoiding gaps between teeth.
• Flat occlusal plane: A uniform plane formed by the occlusal surfaces of the teeth, impacting both function and esthetics.
• Key 2 (Crown Angulation/Mesiodistal Tip): Gingival portion distal to the occlusal portion of tooth crown; variability dependent on tooth type.
• Key 3 (Crown Inclination): Upper incisor's occlusal portion labial to gingival; other crowns’ occlusal labial or buccal surfaces lingual to the gingival portion.

MBT System Design Features

• Full-sized milled metal brackets: A standard bracket design.
• Mid-size (MIM) metal brackets: Alternative bracket design for certain cases.
• Aesthetic brackets (ceramic): A visually pleasing option, with similar strengths to metal brackets.
• Bracket configuration (rhomboidal): This shape reduces bracket bulk while providing better perspective lines, improving bracket positioning accuracy.

MBT System In-Out Dimension Specification

• Measurements of dimensions between teeth in the anterior, providing a consistent approach to anterior teeth positioning
• In general, the dimensions are satisfactory .

MBT System Tip Specification

• The tip feature of the brackets is nearly fully expressed.
• Little “slop” in positioning is possible with wire placement (less than 1 degree).

Chart for MBT bracket positioning chart.

• Charts that present the typical, recommended position for MBT brackets according to tooth position in the mouth.

MBT Treatment Philosophy

• Bracket specification: Precise and standardized bracket design.
• Versatility of the bracket system: Provides options for diverse cases.
• Accuracy of bracket positioning: Precise placement for successful treatment.
• Light continuous forces: Smooth, controlled forces for minimizing adverse effects.
• The .022 slot: The slot size, a key dimension in pre-adjusted appliances.
• Anchorage control early in treatment: Critically important for stabilizing teeth during the initial stages.
• Use of three arch forms: Flexibility to accommodate various arch forms.
• One size of rectangular steel wire: Simplifies treatment planning and material inventories.
• Archwire hooks: Allow use for additional force control mechanisms
• Space closure: Technique for achieving proper space closure in orthodontic treatment.
• Persistence in finishing: Technique for achieving a good stable treatment outcome.

MBT System Arch Form, Wires, and Sequences

• Describes different arch types (tapered, ovoid/tapered, square) and how wires are used in these arch forms for orthodontic tooth movement.
• Highlights considerations in adjusting the shape of wires to match the arch form and tooth shape.

Arch Form Control Early in Treatment

• Focus on ovoid arch forms for inventory considerations to reduce the number of wires that need to be stored.
• 016 HANT wires are easier shape.
• Wires used to create the opening.

Modifications to Arch Form and Archwire Coordination

• Discussions on how to address cases with specific difficulties (e.g. steep Wilson curve, crossbites).
• Utilizing Rapid Maxillary Expansion for specific cases
• Recommended techniques for achieving proper expansion and proper arch alignment with archwires.

Anchorage Control

• Essential in orthodontics for preventing malocclusion from worsening.
• Essential for positioning incisors and other teeth in the face.
• Includes anteroposterior and lateral/vertical aspects .

Principles of Anchorage Control

• Minimizing unwanted tooth movement during initial leveling and adjusting to reduce demands on anchorage
• Providing appropriate support to control the positioning of teeth or groups of teeth.

Torque Issues

• There are possible issues in efficiently positioning the torque of the wire according to tooth type in pre-adjusted systems.
• To improve the efficiency of torque control, upper palatal root torque and lower labial root torque can be introduced into the wires.

Space Closure and Sliding Mechanics

• This part outlines the two differing methods of retraction: individual retraction of canines and incisors, and the en masse method of retracting all anterior teeth simultaneously.
• This portion addresses the selection of rectangular wires for sliding mechanics and their properties in reducing friction during space closure. Various techniques, such as using tiebacks to control retraction, are also discussed.

Settling the Case

• Discusses the importance of precise finishing stages to treat orthodontic cases (errors and corrections).
• Discusses the stages of correction of errors, overcorrection, and case settling.
• Different arch wire options are suggested for settling the case
• There is emphasis on using a chart to determine positioning of brackets on the teeth.

Overcorrection

• In orthodontic treatment, overcorrection is a technique that involves exceeding the desired outcome on tooth movement to account for relapse, inaccuracies, or potential issues in tooth position during the treatment.

MBT treatment-specific aspects of treatment

• Details on specific MBT methods such as the use of differently shaped brackets for teeth to correct positioning and movements

Additional Considerations in Bracket Placement

• Open and deepbite cases
• Fractured or worn teeth
• Palatal contour variances affecting positioning
• Gingival issues impacting the positioning of clinical crowns
• Tooth displacement affecting the visibility of the clinical crown
• Different arch and wire forms that can be useful for different patients with various needs

Test your knowledge on anchorage control and occlusion principles in orthodontics. This quiz covers various concepts, including Andrews' keys of occlusion and the advancements in bracket systems. Challenge yourself and enhance your understanding of effective orthodontic treatments.