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| ORIGINAL ARTICLE |
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| Year : 2023 | Volume
: 12
| Issue : 1 | Page : 11 |
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MH-SETUP, combining Kesling wax-setup with indirect bonding and custom-made brackets for labial/lingual techniques to eliminate the finishing phase
Mohamed A Elkolaly1, Hasan Sabah Hasan2
1 Department of Orthodontic, Royal Dental Center, Alexandria, Egypt
2 Department of Orthodontic, Azadi Dental Teaching Center, General Directorate of Hawler-Ministry of Health; Privet Specialized Dental Clinic, Hawler New, Erbil-, Iraq
| Date of Submission | 12-Jul-2022 |
| Date of Decision | 31-Jul-2022 |
| Date of Acceptance | 12-Oct-2022 |
| Date of Web Publication | 18-Mar-2023 |
Correspondence Address:
Hasan Sabah Hasan
Orthodontic Department, Azadi Dental Teaching Center, General Directorate of Hawler-Ministry of Health; Privet Specialized Dental Clinic, Hawler New
Iraq
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jos.jos_60_22
OBJECTIVE: A novel technique, named the MH setup (MH is an abbreviation for the author's name), was developed to provide an accurate yet simplified method to produce custom-made brackets without bonding errors. This setup aimed to simplify the treatment and eliminate the finishing phase, so that the orthodontist was able to provide better care with less time and lower costs.
MATERIALS AND METHODS: The setup was performed in two major steps: direct bonding on the cast followed by cutting and setting the teeth into precise positions using brackets. The first set of brackets, bonded directly onto casts, oriented the teeth by setting them ideally into wax rims with full control over first-, second-, and third-order bends. The fully engaged archwire used allowed for precise control over the arch symmetry and form. Setting teeth in wax allowed the clinician to refine the occlusion and correct any minor errors that arose during the initial bonding. The second set of brackets, mounted on the fully engaged archwire, featured custom-made composite bases. The transfer tray combined the benefits of its soft inner and hard outer layers, providing control over bonding and later ease of peeling from the brackets.
RESULTS: The patient was satisfied with a full bonding procedure lasting 15 min that remained simple without unnecessary stress. The clinician was confident that the procedure allowed the precise positioning of brackets and simple bonding for all teeth in the arch, combined with the elimination of the finishing phase.
CONCLUSION: The MH technique offered a simple, precise, and inexpensive improvement to the Kesling wax setup. The process allowed for precise bonding without errors or expensive armamentarium. The brackets were transformed into custom-made prescriptions and could be used with labial or lingual techniques. The method allowed for teeth addition, trimming, or overcorrection according to the clinician's preferences. The MH setup facilitated visualization of the treatment objectives with precise locations and the opportunity to revise the treatment plan or to discuss further options with the patient.
Keywords: Custom-made brackets, finishing phase, indirect bonding, Kesling wax setup, labial appliances, lingual appliances
How to cite this article:
Elkolaly MA, Hasan HS. MH-SETUP, combining Kesling wax-setup with indirect bonding and custom-made brackets for labial/lingual techniques to eliminate the finishing phase. J Orthodont Sci 2023;12:11 |
How to cite this URL:
Elkolaly MA, Hasan HS. MH-SETUP, combining Kesling wax-setup with indirect bonding and custom-made brackets for labial/lingual techniques to eliminate the finishing phase. J Orthodont Sci [serial online] 2023 [cited 2023 Mar 25];12:11. Available from: https://www.jorthodsci.org/text.asp?2023/12/1/11/371971 |
| Introduction | |  |
Since the establishment of the orthodontic art by Dr. Angle, clinicians have been faced with the problem that the aims and mechanics of the planning phase are not precisely fulfilled by the conclusion of the space closure phase. Angle successively developed and improved orthodontic appliances in his attempts to achieve these planning goals precisely. Unfortunately, however, such precision was not possible, especially given the complex wire-bending steps performed. After Dr. Andrews later introduced the concept of straight-wire philosophy and used bracket-slot machinery to eliminate wire bending, orthodontic society hoped that the desired precision and control over finishing would be attainable. Unfortunately, Andrews himself realized that no single set of brackets would be able to fulfill the goals of finishing a case according to the desired setup, due to the unwanted effects of tissue responses and bending arches caused by the moments developed during mechanical application.[1]
Subsequently, new orthodontic appliances and treatment protocols were introduced, but failed to completely resolve the problem. Human error introduced by the orthodontist produced bonding mistakes sufficient to cause problems at the conclusion of treatment. Further, the finishing phase consumed a substantial portion of the treatment time. All clinicians are accustomed to a finishing phase at the conclusion of treatment, with this phase ideally lasting less than six months; the greater the expertise of the clinician, the earlier the finishing phase occurs. For a two-year treatment protocol, the finishing phase could consume a quarter or more of the treatment time.[2]
Before the introduction of nickel titanium archwires and titanium molybdenum archwires, orthodontists finished cases using only stainless steel (StSt) archwires, which lacked the flexibility necessary for wire bending. If the errors in the bracket positioning were sufficiently small, the StSt bending could be conducted without imposing heavy forces over the roots. However, when the errors in bracket positioning exceeded one millimeter, the only option was to cut the StSt wire into pieces and use vertical elastics or allow time for the teeth to settle into good interdigitations.[1],[3]
Kesling introduced the positioner to aid the correct settling of teeth, formulating an acrylic bite plane that joined two settled arches. The patient was instructed to bite on the positioner for four hours each day to guide the teeth into their ideal positions. A classical Kesling wax setup was composed of the following steps.[2] The clinician performed a panorex film to check for teeth angulations and lateral cephalometric films to scan for teeth inclinations. Archwires were removed and impressions of the upper and lower arches were taken, then poured with white orthodontic stone.[4] Teeth were marked and numbered to allow for easy identification after separating them. Linear marks were identified on the casts representing the facial midline, the upper dental midline, and the lower dental midline. The upper and lower canine cusps were also marked. The mesiobuccal cusps of the upper and lower first permanent molars were identified and marked with vertical lines. On the back of the casts, the last molars were marked by vertical lines through their buccal and palatal cusps to identify the arch form.[5],[6] Later, teeth were cut with precision using a fine saw from the gingival side until just before the contact points. A clean line fracture was then produced by using small manual forces to propagate the cut through the contacts. Teeth were set into the wax to represent the ideal positioning needed to resolve the errors detected by the X-rays and the cast's occlusion. Each corner of the cast was cut and set in a separate step to allow the other corners to be used as a vertical reference guide.[7] After completing the setup, the new positions of the canines, molars, and midlines were marked on the casts by red lines to delineate the differences between the pre- and post-setup occlusion.[8] Reviewing these steps, it is clear that this process was technique-sensitive, time-consuming, and not user-friendly, hindering its regular, and consistent application across cases.[8],[9]
In this paper, the authors introduced a novel wax setup technique that facilitated tooth positioning and eliminated the risk of errors. This technique was easy to use in both labial and lingual appliances. Furthermore, it allowed the removal of the finishing phase, hence reducing the treatment time. The technique, named the MH wax setup based on the authors' names, was explained through a real case study to illustrate its component steps and requirements.
| Materials and Methods | | |
Records acquisition
Before commencing the procedure, the complete set of patient records was acquired. Orthodontic impressions for orthodontic casts and panorex and lateral cephalometric X-rays were performed. Extra- and intra-oral photographs were recorded. The maximum intercuspation bite and centric relation bite were registered using additional silicon bite registration material.
The centric relation was measured by placing the patient into a supine position and inserting a tube between his incisors. The tube was less than 1 cm in diameter to prevent driving the condyles out of the rotational phase of movement. When the patient was placed into the supine state, he was instructed to drive the mandible and tongue backward and to bite on the molars, allowing the tube to disocclude the teeth. Bite registration was dispensed between the teeth and allowed to set.
Cast mounting and markings
Casts were mounted on simple hinge articulators, one set representing maximum intercuspation and the other based on the centric relation record. After mounting, the records were removed, and the casts were allowed to close until the first point of contact in occlusion. The casts' mountings were compared and studied to identify the mandibular shifts in the case.[10] The pretreatment midlines and mesiobuccal cusps of the first molars were recorded on the casts' bases in stable black ink to register the pretreatment occlusion [Figure 1].
Initial bonding of the setup casts
The setup casts were bonded using the preferred prescription of the clinician according to the treatment plan. In this example, the slot size selected was 0.018” × 0.025” and the MBT Dentaurum bracket prescription was used. A Boone gauge was used to bond the brackets to the cast. The leveling was performed according to the following design. The upper centrals and all premolars were bonded at a fixed value, denoted X mm. With respect to this value, the upper lateral incisors, all lower incisors, and all first molars were bonded at X – 0.5 mm. The second molars were positioned at X – 1 mm and the canines at X + 0.5 mm. These rules allowed for the development of good aesthetics while also providing a mutually protected occlusal scheme with canine guidance. The measurements in our example were designed with X = 4.5 mm. Thus, the upper central incisors and all premolars were bonded at 4.5 mm; upper lateral incisors, all lower incisors, and all first molars at 4 mm; all second molars at 3.5 mm; and all canines at 5 mm. The panorex radiograph was displayed beside the working area to help identify the correct angulation of each bracket relative to the long axis of its associated tooth. The brackets were glued to the cast using 3M orthodontic light-cured composite [Figure 2].
Sectioning casts and separating the teeth
A thin, sharp saw was used to cut at least 5 mm below the cervical lines of the teeth with a single horizontal cut to free the arch from the cast's base. Subsequently, vertical fine cuts through the papillae were directed from the gingiva upward until 1 mm from the contact area. Teeth were separated using fine hand pressure to allow for crack propagation from the vertical cuts through the contact points. There was no need to mark the teeth because each tooth was easily identified by its attached bracket. The stamps of teeth were trimmed to prevent any interference during setting into the wax rims. Finally, teeth widths were compared on the cut teeth with the other solid set of casts to ensure no changes were introduced [Figure 3].
Initial wax setup steps
Based on the desired treatment plan, the clinician was required to determine the expected arch form. Functional orthodontists typically require that the original arch form be preserved for stability, while aesthetic orthodontists favor the expansion of the arches to create a full smile spanning 75% of the patient's intercommissural width during an unposed smile. The expected arch form and shape were represented by a 0.018” × 0.025” StSt wire. Teeth were attached to the archwire using the brackets, ensuring that the dental midline was coincident with the archwire's midline. The process was performed from the central incisors, proceeding backward.
The bases of the casts–still attached to the articulators–were covered by thick wax rims of #7 hard setting wax, 8 mm in height. The wax was cut from the midline as a trench and softened by flame. Teeth (attached to the wire) were set into the rims, beginning with the lower arch. Small wax stamps were placed onto the occlusal surfaces of the first molars, first premolars, and midline, then a glass slab was secured onto the arch. A cell phone with an orientation freeware application called “Spirit Level” (designed by Keuwlsoft Androids) was placed onto the glass slab to adjust the orientation; the occlusal plane should form exactly the same angle with the cast base as the occlusal plane forms with the true horizon on the cephalometric film. The occlusion was set and the wax was allowed to solidify. The upper arch was then set and adjusted to close in a tripod relationship with the lower adjusted arch [Figure 4].
Refining the occlusion and settling teeth together
The occlusion and the setup were examined labially and lingually to identify any refinements that were required [Figure 5]. The archwires were removed and refinements were performed to obtain the ideal occlusion, which was defined by the standards detailed by the ABO. This involved leveling the marginal rides and contact points to match one another. In particular, note that no complex adjustments were required because the brackets were able to align, tip, and torque the teeth into ideal positions due to the use of fully engaged archwires to express the prescription. Brackets and wires were then removed.
Revising the treatment plan
The new positions of midlines, canine cusps, mesiobuccal first molar cusps, and distolingual last molar cusps were compared to the precut markings. The treatment plan was checked and the aims were revised according to the desired movements. The anchorage was checked by calculating the molars' mesial shifts; the form and shape of arches were compared, and teeth angulations and inclinations to the occlusal plane were revised. Any necessary teeth additions (due to abrasions) or interproximal reductions (due to Bolton discrepancies) were recorded and performed [Figure 6].
Registering the changes performed on the setup sheet
The setup sheet included the following information. First, the patient's name, age, and date of setup were recorded. Extractions or artificial teeth additions, basal bone adjustment through growth modification or surgery, and necessary adjustments to incisors as retraction/protraction or intrusion/extrusion were documented. In addition, the curve of Spee leveling through bite opening and closure mechanics was noted. The records also included midline adjustments and directions; arch forms and arch widths; and the relationships of molars, canines, and incisors. In extraction cases, anchorage and space loss were registered, while distalization and space gain were noted in non-extraction cases. Finally, interproximal reductions or buildups required for good occlusion were calculated and recorded.
Stabilizing the teeth for the following steps
A layer of plaster of Paris was painted onto the wax rims to hold the teeth securely and permanently in their final positions. This prevented any deviations under the forces of the following steps [Figure 7]. Casts were then refined by white polishing using slow-speed rubber cones manufactured by 3M.
Final bonding of the setup casts
The desired set of brackets (either lingual or labial) needed for the patient were attached to their fully engaged archwire (either 0.018” × 0.025” or 0.021” × 0.025”) and adjusted to the facial centric point of the central incisors. These archwires guide the proper positions of brackets relative to the other teeth. A small quantity of 3M orthodontic bonding composite was added to each bracket base. The archwires with the complete set of brackets were then pressed against the teeth and cured for 40 s per tooth. The orthodontic composite acted as a custom-made bracket base [Figure 8]. Subsequently, the archwires were removed, leaving the brackets ready for the transfer tray [Figure 9]. Please note that the authors did not see any necessity for the use of prescription brackets in the final step due to the customization of the composite base for each tooth. Hence, the authors used edgewise Dentaurum brackets for the labial appliance cases.
Formulating the initial layer of transfer tray
A 1-mm layer of thermal, soft, clear, vacuum-formed sheet was heated and pressed onto the setup casts to cover the brackets and the occlusal, labial, and lingual surfaces. The tray was allowed to set, then was cut with a number 10 surgical scalpel into pieces representing each tooth. A small amount of flowable 3M composite was placed on the inner side of the separated trays on the opposite side of the brackets. The separated trays were pressed onto the other set of pretreatment casts and cured for 10 s per piece to fix them accurately and avoid any later dislodgements [Figure 10].
Formulating the final layer of transfer tray
Another 1-mm layer of thermal, hard, clear, vacuum-formed sheet was pressed over the entire cast together with the initial transfer pieces. This formulated a final full transfer tray that fit the patient's malocclusion. The tray was cut as arch-shaped and trimmed. At this point, the transfer tray was composed of an outer hard layer of 1-mm thickness that enclosed inner soft pieces of 1-mm thickness. The soft pieces held the brackets with their custom-made composite bases [Figure 11].
Intraorally bonding the brackets to teeth
The patient's teeth were prepared, cleaned, and polished. All teeth were etched for 20 s using 3M 37% phosphoric acid, then washed for 60 s and gently dried until a chalky-white color appeared. Orthodontic 3M light-cured bond was spread over the etched surfaces. Additionally, the composite bases were etched using 3M 37% phosphoric acid for one minute to remove any surface impurities and activate the surface tension layer, then thoroughly washed and dried. A thin film of 3M orthodontic bond was painted onto the composite bases and a tiny drop of 3M orthodontic composite was applied to that layer [Figure 11]. The transfer tray was then pressed onto the arch, with firm hand pressure distributed at the midline, premolars, and last molars. Light curing for 40 s on each tooth was performed to complete the bonding. The transfer tray was then peeled off the patient's teeth and any excess or flashes were cleared using 3M multi-fluted, composite-removal burs. Finally, super-curing was performed for 40 s on each tooth to ensure maximum bonding strength was attained [Figure 12] and [Figure 13].
| Results | | |
The patient was satisfied with the bonding visit, which totaled 15 min in duration. The brackets were positioned in ideal locations without any need for readjustments. Furthermore, neither back pain nor neck pressure was experienced by the clinician because the procedure was performed on the casts with a wide field of vision. Instead of conducting bonding over two visits, the bonding of all teeth before the second molars was performed accurately in a single visit. The duration of the laboratory procedure, performed by an experienced clinician and/or technician, was 2 hours.
| Discussion | | |
Bracket positioning is one of the most important yet challenging procedures of treatment. Some clinicians rightly consider the bonding process the most important component of the treatment; well-executed and precise bonding visits vastly minimize the finishing phase or even eliminate it entirely.[11] As clinicians are human, frequent errors are realistically inevitable; however, many methods have been suggested to avoid such errors. For example, one recommendation was to use a digital setup with a 3D computer program and print a plastic cast to obtain precise bracket placements. While effective, this technique was limited by the excessive cost of those programs and the 3D printing, as well as the special training and time requirements to learn to control teeth digitally, rendering it unattainable for many clinicians.[12]
An alternative approach involves bonding brackets manually, contingent upon the clinician's experience. After this bonding, a full arch scan of the teeth and brackets is performed to register the bonding. Wire bending can be performed by a robotic arm controlled by a complex computer algorithm to ensure precision, as used by the Sure Smile company to successfully provide a complete set of wires fit for bonding.[13] Again, this technique is effective but expensive and is not available to all orthodontists worldwide. By contrast, a different solution is to scan a patient's teeth and manufacture a custom-made bracket designed specifically for that patient. One example of this approach, recognized for its efficiency, was 3M's well-known Incognito system. This system contained gold material and was used effectively as a lingual appliance for many years.[14],[15] Needless to say, the cost of such an appliance was extremely high, and its availability was limited to orthodontists who had attended a specific course with 3M and had access to the facilities needed to scan and communicate with the Incognito department, combined with a patient who could afford the cost.
The Kesling setup is an old but effective technique routinely used for the visualization of treatment objectives, communication between different branches of dentistry during interdisciplinary approaches, and indirect bonding.[16] For indirect bonding, many prestigious orthodontic laboratories employ a lingual bonding apparatus to adjust the tip, torque, and orientation of each bracket on casts. Apparatuses such as the Ray Set or In-Tendo are used extensively, although the costs of such apparatuses are high and laboratory fees must be added to the treatment. Clinicians who have used these techniques are impressed that even labial bracket cases have been referred to those laboratories for precise bonding using indirect techniques.[16],[17]
In this paper, the authors presented a novel approach for modifying the Kesling wax setup to avoid complexities. Moreover, steps were introduced for the indirect bonding of custom-made bracket bases to help achieve the aims of Dr. Andrews of straight-wire treatment and the elimination of the finishing phase. A careful examination of the Kesling wax setup methodology revealed that, while the technique was simple, the hand-setting was more prone to errors than direct bonding. Hence, our novel approach was developed to use the brackets in our hand to aid in the precise setting of teeth in wax rims as an efficient and cheap replacement for complex apparatuses that settle teeth in 3D positions in laboratories.
Our approach began with data acquisition to formulate a treatment plan, which is essential to inform and direct the application of even the best of techniques, and is hence the critical starting point for any success in treatment methodology. Thus, collecting the patient's full records, including questionnaires on their history, extra- and intra-oral photographs, panorex and cephalometric radiographs, impressions, and bite records, was mandatory to study the case. Because the MH setup would involve planning the necessary movement and final teeth positions, it was important to register two sets of orthodontic casts. The first set was mounted in the maximum intercuspation relationship, while the second was mounted in a centric relation status.
The centric relation record was registered using the patient's muscles to drive the mandible in the most upward and backward position possible using muscles of mastication with the elimination of any posterior teeth contact. This was possible by using a small, rounded tube of less than 10 mm in diameter between the incisors to disocclude the posterior teeth. The patient was placed in a supine position and instructed to pull his mandible upward and backward as much as possible with the tube between his incisors. This provided a firm reference point for the condyles' centric relationship. Placing the casts on the articulators while knowing the precise diameter of the separating tube was sufficient to decrease the articulators' pin to precisely compensate for the thickness of the bite registration material.[18]
Articulators are available in different categories and designs. Most articulators used to examine the occlusion are semi-adjustable, and non-ARCONs are preferred over ARCONs in orthodontics.[18] In this study, the authors used simple hinge articulators as there was no need to modify the relationship of the teeth to the TMJs. These hinge articulators were simple, user-friendly, and readily available in any laboratory, and sufficed to compare the maximum intercuspation position and the centric relation position. If, in another case, the clinician decided that dramatic changes were needed, a semi-adjustable articulator could be used instead.
In the classical Kesling setup, cast markings are paramount, and no setting can be performed without complete measurements. By contrast, in the current MH setup technique, cast markings are only used to calculate pre- and post-setting positions. Hence, it was not mandatory to calculate complex measurements and 3D teeth positions. The key principle of the MH setup was to use brackets with a preferred prescription to precisely set the teeth in wax without the chance of technical errors. In this case, the clinician used the preferred prescription of brackets with a 0.018” slot and bonded these directly onto the casts with clear vision and precise gauges. The authors preferred a scheme that bonded the canines 0.5 mm taller than the central incisors and premolars, which guaranteed a canine guidance scheme, as 0.5 mm in each of the upper and lower canines provided 1 mm of canine height above any other tooth in the arch. The upper lateral incisors and the lower incisors were bonded at 0.5 mm less than the upper centrals to support aesthetics and maintain a 2 mm overbite relationship. The first molars were bonded at 0.5 mm less than the premolars, and the second molars at 0.5 mm less than the first molars, to allow for smooth arch transitions and avoid any posterior teeth interference. In an arbitrary case, the preferred bonding scheme could be selected according to the clinician's preferences, allowing for the inclusion of teeth trimming or additions. The bonded brackets would be used for teeth identification after sectioning; hence, no teeth markings were necessary. Moreover, a fully engaged archwire could be attached to the teeth to automatically express the prescription.
Another problem encountered using the classical technique is the loss of vertical dimension. This necessitates separating teeth in stages, acting on one side at a time. Comparatively, in this work, the use of simple hinge articulators to preserve the relationship and maintain the vertical dimension efficiently facilitated the methodology. Moreover, the risk of loss of arch form and even distortion or asymmetry was avoided by using an archwire to set the brackets according to the desired specifications. This simplified the setting of teeth into wax rims into a single step. An additional advantage of using the archwire-bracket interface was the use of a glass slab to adjust the inclination of the occlusal plane according to the readings of the cephalometric film. The arch and teeth were cut with a very thin and sharp hand saw, offering the finest and most precise control over the cutting procedure, rather than the suggestions of burs and discs in some literature. Further, the cuts were guided to end 1 mm away from the point of contact to avoid trimming the teeth interproximally. One well-known property of gypsum is its brittle nature that creates fine fractures through crack propagation. Pressing the teeth together with light finger pressure was sufficient to provide separation at the contact level without damage. Teeth widths after sectioning were compared to pretreatment casts to ensure precision and accuracy of interproximal widths.
After attaching the cut teeth to the fully engaged archwire, they were ready to be set into wax rims. Cast bases, still mounted on the articulators, were amended with thick wax rims of hard setting wax. A central groove was cut into the wax to receive the arch set. The wax was softened by flame and the archwires, with teeth attached, were set into the wax. A glass slab, complemented by the use of an orientation program on a cell phone placed atop the slab, was used on the occlusal plane of the archwire-teeth to help with 3D orientation, taking care to set an occlusal plane angle similar to that of the cephalometric film. This provided a realistic simulation of the final positions after treatment rather than simply using a flat, unrealistic occlusal plane. After the wax solidified, the upper arch was set following the same procedure, but the orientation of its occlusal plane was adjusted to occlude on the lower arch in a tripod relation. The resultant occlusion was consistent with that expected to be achieved clinically using direct bonding techniques. This concluded the first phase of the MH setup.
In the next phase, the occlusion was inspected and modifications needed were recorded. The brackets with fully engaged archwires were efficient in adjusting the tip and torque of the occlusion. The archwires should set teeth in the desired arch shape and form according to the wires selected, recalling that the occlusion, not the brackets, is the focus and defines the success of the treatment. Hence, revising the occlusion by hand according to the ABO standards was mandatory for planning refinements.[19] Teeth positions with respect to pre-cut markings and anchorage were calculated and assessed. Archwires with brackets were removed and minor detailing performed to achieve the best possible occlusion. A layer of gypsum was painted onto the wax rims to stabilize teeth positions and avoid minor movements during the subsequent steps; this was important because wax is known to suffer dimensional changes under pressure or due to temperature. Later, teeth were polished with fine white rubber cups to restore clean surfaces without changing the labial surface anatomy. From this point onward, the orthodontist was formulating custom-made brackets for a particular case using composite as a special base.
The final set of brackets that the clinician aimed to bond to the patient's teeth was selected. This set could be labial or lingual brackets, with slot sizes of 0.018” or 0.022” according to the clinician's preferences. In this study, the authors used edgewise bracket prescriptions as they saw no need for more expensive sets, since the composite would act as a custom-made base. The only difference between prescription and edgewise brackets was that edgewise brackets would provide thicker composite bases. Moreover, the clinician could select a 0.018” slot for the incisors and a 0.022” slot for the canines and posterior teeth, thus providing perfect control over the incisors' torque while using sliding mechanics in extraction cases.[20] The new set of brackets were attached to a fully engaged archwire with composite added to the bases, then pressed and cured onto the teeth using the wires as a guide. The patient then received custom-made brackets to adjust the occlusion. Care should be taken to adjust the levels of archwires to coincide with the center facial point of the central incisors; all other teeth automatically follow from that starting point.
Transfer trays were fabricated by removing the wires and pressing two layers of vacuum-formed thermoplastic sheets onto the setup. The first layer was soft, to hold the brackets and fill any undercuts precisely, and cut using a large surgical scalpel. The pieces were transferred to the original malocclusion cast. This inner sheet was chosen to be soft to allow it to be peeled off without dislodging the braces. In contrast, the purpose of the second layer was to act as a rigid transfer to bond the dentition in one step after the preparation of the teeth. Using that protocol, the usual sequence of archwires was to be used until reaching complete engagement and obtaining a perfect occlusion identical to the MH setup. The pieces of the first layer were fixed onto the pretreatment casts using small dots of flowable composite, which were added to the fitting surface away from the brackets and cured to precisely stabilize the sheets on the casts.
The night before the bonding appointment, the patient's teeth were cleaned, scaled, and polished to provide a fresh surface for adequate bonding strength. The teeth were thus ready to be etched and bonded the following day. Immediately prior to intraoral bonding, the bracket bases on the tray were etched for one minute with 37% phosphoric acid to activate the surface layer and remove any impurities. After etching, the patient's teeth were painted with orthodontic bond, as were the bracket bases.[21],[22] A very small amount of composite was added to each bracket base, and the tray was pressed onto the patient's teeth, then cured for 40 s per bracket. Bonding was performed one arch at a time. Trays were peeled carefully from the patient's teeth and any excess composite was trimmed. Note that a very small amount of composite was used in order to minimize the residual flashes requiring trimming after tray removal. In general, the more excess composite that appeared on teeth, the more difficult the cleaning. Final super-curing of each bracket was recommended to obtain maximum bond strength.
A thorough evaluation of the described procedure yielded the following advantages and disadvantages. First, a simple and precise procedure was performed accurately, and ideal final teeth positions were achieved using a logical and straightforward technique. Compared with the classical Kesling setup that cuts teeth and sets them one by one, setting the arch in one step per the MH setup was extremely simple and accurate. The use of prescription brackets to adjust the first-, second-, and third-order positions of each tooth, together with a fully engaged archwire to guard the arch shape and form, was simple and precise. The use of a glass slab with an orientation program to calculate the occlusal plane in 3D was contemporary, easy, and user-friendly. The use of a final, fully engaged archwire to convert the brackets into custom-made brackets with customized composite bases was innovative and accurate. Further, the transfer tray, composed of a soft inner layer and a hard outer layer, was fast, simple, and combined the benefits of both materials.
Conversely, the disadvantages of the MH technique included the application of an extra set of brackets, the use of double sets of casts, and the need for two stages of laboratory bonding instead of a single direct clinical bonding procedure. However, the price of an added set of brackets, compared to that of the conventional six months of the finishing phase with an expert clinician, favored the use of the extra brackets. As is widely recognized, “time is money,” and the cost of time typically outweighs that of any material. Thus, the two hours of laboratory time preparing for the MH setup and the additional cost of an extra set of brackets were insubstantial considering the accurate final bracket positioning and elimination of the finishing phase. Finally, orthodontists should note that the finishing phase is implemented to correct for errors, primarily those in bonding and mechanics. The bonding errors were eliminated using the MH setup technique, but the orthodontist was still required to use correct and careful mechanics to avoid introducing unnecessary complications to the treatment procedure.[23]
| Conclusion | | |
- The MH wax setup was able to maximally simplify the original Kesling wax setup while avoiding its potential for introducing errors.
- The MH wax setup provided a custom-made bracket set for precise clinical teeth adjustments, using customized composite bases.
- The MH wax setup could be employed with labial or lingual appliance techniques.
- The MH setup was able to provide teeth setting and occlusal adjustments according to the desired prescription required by the clinician.
- The entire procedure of the MH setup consumed 2 hours of laboratory work with an experienced clinician/technician, saving six months via the elimination of the finishing phase and avoiding unnecessary rebonding or wire-bending procedures.
- The use of two sets of brackets, one to adjust the setup and the other for clinical bonding, provided precision, accuracy, and custom-made bases without any complex armamentarium.
- Any overcorrections, special prescriptions, teeth additions, or IPR (Interproximal reduction) could be easily implemented as part of the procedure.
- The MH setup allowed for the visualization of treatment objectives before commencing the treatment on the patient. This was the most accurate way to ensure that a given treatment plan was the best possible for that patient, particularly in borderline cases.
- The clinician could still apply cone-beam scans and computer prediction software to help plan the treatment, but the MH setup provides the only true blueprint of the final result.
.The authors wish to thank the lab staff and patients for their cooperation during the study and the orthodontic procedures.
Author contributions
All the article authors contributed in an equal manner from writing to publishing.
Ethical Policy and Institutional Review Board statement
Not applicable in this study.
Patient declaration of consent
Taken and attached.
Data availability statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13]
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