|Profitable Dentistry - September 1997
The most dramatic revolution in orthodontics since 1925, when the edgewise bracket was developed, has happened! The development of an edgewise type bracket that not only commands precise finishing but provides an efficient and logical means of arriving at the finishing stage of treatment.
By combing the rapid tooth movement, light forces, and minimal anchorage strain of the light wire technique with the precise finishing advantages of the channel type bracket, the best of both techniques can be realized.
The Tip Edge bracket does just that. The unique design of the Tip Edge bracket, which allows free tipping in one direction, without archwire deflection, also permits the use of larger archwires with no flexing or bending. This is possible because as crowns tip, the archwire slot increases from .022 to greater than .028 yet closes back to .022 during the finishing stage for precise control.
The Tip Edge operator routinely progresses directly from .016 to .022 round or even .0215 x .028 square for final uprighting and torquing. This feature enhances patient comfort and reduces operator workload, allowing fewer archwire changes and archwires during the course of treatment.
Tip Edge (the differential force technique) is divided into three stages of treatment - each stage is amazing.
The first stage, because of relatively large scale movements and the efficiency with which they take place, is the most dramatic. These types of enmasse movements, unique to the differential force technique, are possible because of the design of the bracket.
The Tip Edge bracket, developed br Dr. Peter Kesling of Westville, Indiana, in the early 1980s, is a modified edgewise bracket having diagonally opposed corners removed to allow free crown tipping under light(1.5 to 2.0 oz.) elastic force in one direction and controlled uprighting in the other. The limiting surfaces of the bracket control the amount of tipping and uprighting in each direction.
At the banding appointment, .016 archwires, of proper strength and resiliency, are placed along with light force (1.5 to 2.0 oz.) intermaxillary elastics. The quickness of the bite opening eliminates anterior tooth interferences and bracket displacement.
From the beginning appointment, the crown of each tooth starts moving toward its final postition, independent of one another. Simultaneously with the place archwire appointment, the necessary corrections are initiated. No longer is it necessary to address each aspect of the malocclusion separately. Bite opening (closing), molar closure, rotations, anchorage control, crossbite correction, and midline correction start from the place appliance appointment.
This unique environment, Tip Edge brackets, .016 non-relaxing high tensile strength wire-light (2 oz.) intermaxillary elastics worn 24 hours/day, is responsible for the rapid tooth movement of the anterior teeth and relatively undisturbed anchor molars.
One of the major benefits of light forces and continuous tooth movement is increased patient comfort. Patients seldom complain of sore teeth during Tip-Edge treatment. Patients are normally seen on a six-week appointment basis which results in fewer trips to the office and obviously reduced treatment and chair time for the operator.
Since archwire forces are used to move teeth only during the first stage of treatment, with differential force tchnique, there are fewer archwire changes. Most cases are treated using only four to six archwires during the entire treatment.
REQUIREMENTS OF THE FIRST STAGE OF TREATMENT
Bite opening (closing) is accomplished through a combination of judicious bends in the .016 archwire, light (1.5 to 2 oz.) Class II elastics and the Tip Edge bracket allowing the roots of the teeth to take the paths of least resistance. With the differential force technique, there is no need for functionals, bite planes, or other auxiliaries to open the bite.
Anterior crowding is attended to through the use of nitinol or coax wire in conjunction with the main archwire. A loop archwire or simply tying with elastic thread to the main archwire also will correct the crowding because of the freedom the bracket allows the teeth to enjoy during the first stage of treatment.
Spaces in the anterior segment can be closed with light elastomeric chains, or in minor space situations, simply attach the elastomeric circle (holding the bracket to the archwire) to the circles on the archwires.
The archwires can be overexpanded or contracted to correct crossbites concurrently with the other first stage requirements - inter-maxillary crossbite elastics are added as necessary. Severe maxillary deficiencies in young and adolescent patients are corrected with "rapid palatal expansion" before archwire placement. RPE is the only auxiliary used with differential force technique.
Rotations in the anterior segment are accomplished with rotating springs - usually completed in one or two appointments. The molar relationships and anterior posterior dysplasia is corrected by the anchor and bite opening bends in the archwire and the light Class II elastic force.
Light intermaxillary forces are necessary to tip the anterior teeth to an edge-to-edge relationship by the end of the first stage. The synergistic effect of the archwire forces and Class II elastics automatically correct the molar relationship to a Class I by the end of the first stage of treatment. The elastic forces are light enough to not have significantly disturbed the anchor molars during this stage. The first stage of treatment lasts from three to six months, depending on severity of the case.
The magic of the first stage - moving the entire maxillary anterior segment simultaneously to an edge-to-edge relationship with 1.5 to 2 oz. of force while completing the other first stage requirements and not unduly taxing available intraoral anchorage.
Eliminating the relatively heavy (6 to 16 oz.) forces routinely used during conventional edgewise treatment coupled with one-point contact between archwire slot and archwire eliminates adverse archwire deflection and actually enhances bite opening and anterior tooth retraction during this amazing first stage of treatment.
NOTE: Tip Edge is a registered trademark of TP Orthodontics, Inc., LaPorte, Indiana, USA.