The present invention relates to the field of orthodontics, more particularly to computer programmed indirect bracket bonding, more specifically to bracket holders and transfer trays.
Orthodontics is a branch of dentistry involving the treatment of irregularities in the teeth and jaws, including the use of braces. Orthodontic brackets are bonded to the teeth where a wire, called an arch wire, is attached to the bracket. The dentist determines the position of each bracket. The more accurately the brackets are placed the less the wires must be adjusted to achieve a perfect result. It is common that brackets must be repositioned on the teeth. The concept of not adjusting arch wires was advanced by Dr. Andrews when he developed the straight wire appliance (1970). The next concept was the brackets could be fitted more accurately on models of a patient's teeth. The brackets are positioned on the model and a dental tray was vacuumed over the model with the brackets. The brackets are positioned in the tray, the teeth are etched and the tray is placed over the patient's teeth where the brackets are bonded to the teeth.
The computer arrives and is programmed to determine the correct bracket position on a digital 3D image of the tooth. Digital scanners were developed which gave the computer a three- dimensional image of the patient's teeth. The computer can create a three-dimensional digital image of a model with an image of orthodontic brackets in the correct positions (U.S. Pat. No. 9,418,474). The computer is capable of creation of a three-dimensional creation of a tray to house the orthodontic brackets and program a 3D printer to form the tray with the receptacles for the brackets. This further refined in U.S. Pat. No. 9,622,834 which provides for scanning the patient's teeth.
The current state of the art requires digital trays rigid enough to not allow the brackets to migrate which makes the trays difficult to remove once the brackets have been placed in the mouth.
The removal difficulty increases the more crooked the teeth are. The hard trays make it hard to load the bracket. When brackets have been loaded in the tray the tray material encloses much of the bracket which makes it difficult to load the adhesive and limited access to remove the adhesive flash.
The present invention Is directed to an indexing pin which is snap locked to an orthodontic bracket and a geometric tail which snap locks into a dental tray. The indexing pin is comprised of hard material such as rigid plastic. The indexing pin has a longitudinal tail with a geometric shape. The indexing pin has an opposite end which is precisely fitted to an orthodontic bracket to create a snap lock when the two are fitted together.
The function of the indexing pin is to precisely lock an orthodontic bracket in its computer chosen position to a clear orthodontic tray with minimal or no contact between the tray and the bracket. A tray is then vacuum molded over the model. The tray is trimmed to extend axially from the occlusal of the teeth to include the enclosure of the pins. This smaller tray has distinct advantages in access to the brackets and ease of removal of the tray following bonding of the brackets in the mouth.
The geometric male body snap-fits into a matching female receptacle in the tray. The geometry of the tail may include rings around the axis and a ring at the end.
In a preferred embodiment, the patient's teeth are scanned to a computer which determines the ideal positions of the bracket/attached pin combinations on the teeth. The computer then designs the reduced size tray containing the female receptacles for their corresponding mail indexing pins. The computer commands a 3D printer to print the occlusal index using a rigid plastic.
The male member of the bracket/pin combination is placed into its respective female receptacle. The teeth are etched and the tray with pasted brackets is placed on patient's teeth. Light cure paste is cured with a light cure gun through the clear plastic and the tray is removed.
In another embodiment, the bracket part of the indexing pin has four corners facing the bracket. Each corner has a rounded protrusion. Each bracket has four rounded recesses to match the rounded protrusions on the indexing pin. The protrusion/recess combination produces a locking affect when the pin and bracket are placed together.
The invention is comprised of a digital indirect bonding assembly 1.
The female index receptacle 19 is shown in
The patient's teeth are scanned 105. This is the preferred embodiment in the present invention; but, a set of the patient's models can be scanned. The scans are then transmitted 106 to the computer. The next step is programming the computer 107 to determine the position of the index pin bracket combination on each of the patient's teeth. The next step is programming the computer 108 to form an occlusal index which contains female geometric index pin receptacles to precisely match in shape and snap receive their respective male index pins. Each male index pin holds its respective bracket in its correct computer selected position. The occlusal index will be ⅓ the height of a normal dental tray.
The occlusal index is formed 109 in a 3D printer using dental tray material. Male index pins with their attached brackets are each placed 110 in their respective female receptacles. The patient's teeth are etched 111 where the brackets are to be placed. The next step is placing bonding material on each bracket. 112. The brackets may also be pre-pasted. The next step is inserting the occlusal tray 113 containing the indexing pin bracket combinations over the occlusal of the patient's teeth and hardening the bonding material 114.
The present invention facilitates the removal of the tray from the patient's mouth: but, if it is difficult to remove, cutting the index pins 115 with an orthodontic pin cutter makes removal very easy. Sectioning the occlusal tray 116 also enhances removal of the occlusal index. The smaller occlusal index makes cutting easy.
The next step is removing the occlusal tray 117 from the patient's mouth. Another situation involves replacing a loose or broken bracket 118 wherein the selected tooth portion is cut from the occlusal tray; Next a new bracket indexing pin combination is placed 119 into the female recess; and the indexing tray is placed over the etched tooth and the bracket is bonded 120 to the tooth. An additional situation involves changing the position of an indexing pin bracket combination 121 in the computer program and preassembling 122 the bracket with the jig.
Additional steps involve making the indexing pin snap lock with the orthodontic bracket by placing rounded projections 123 on four corners of base adjacent to the bracket; and forming indents 124 in the bracket to fit the rounded projections.