A PATIENT-SPECIFIC CUSTOMIZED H PALATAL PLATE FOR EN MASSE MAXILLARY ARCH DISTALIZATION AND A METHOD

Abstract

Disclosed herein is a patient specific customized H palatal plate (HPP), as shown in figure 1, for en masse maxillary arch distalization, which is characterized by; a) a central assembly consisting of three screw tubes, one anterior (to be placed between the first and second premolar), and two posterior (to be placed between the second premolar-first molar) connected by a major connector, the palatal bar, to secure the device to the palatal area, wherein, the two posterior holes are more lateral (3 to 4 mm) to the midpalatal suture; and b) distally curved lever arms having three hooks/notches originated from ends of the palatal bar bilaterally at the region of the first maxillary molar and extend until the second molar, to improve the force control vector and to engage the elastomeric chains for traction. Also disclosed herein a method for fabrication of patient specific customized H palatal plate (HPP)

Specification

A Patient-Specific Customized H Palatal Plate for
En Masse Maxillary Arch Distalization and a Method of Fabrication Thereof.

FIELD OF INVENTION:
This invention broadly relates to an anchorage device pertaining to the field of Orthodontics. More specifically, the invention relates to patient specific customized H palatal plate for en masse maxillary arch distalization and a method for fabrication thereof.

Background and prior art:
Maxillary molar distalization, a non-extraction treatment option in orthodontics, is in use for over 100 years to treat cases like class II malocclusion. Maxillary molar distalization technique is generally utilized to gain space to relieve crowding and to reduce the increased overjet. Although, other treatment options are also available to gain space which includes extraction, expansion, and orthognathic surgery etc.; however, the severity of malocclusion and the facial profile usually rule these choices in addition to the cost of the treatment, treatment time and patient's cooperation. A number of patients are seeking for correction of their malocclusions, including patients present with a history of previous orthodontic treatment. Orthodontists performing retreatments, due to poor mechanics, in their practice are facing additional difficulties, in view of specific demands for excellent results and efficient treatments.
Skeletal Class II malocclusion or Distocclusion, term coined by Lischer in 1933, is attributed to a prognathic maxilla, a retrognathic mandible or its combination thereof. Such malocclusion was further subdivided by Salzman in 1950 into Class II malocclusion into Division 1 and 2. The prevalence of Class II Division 1 in the Indian adult population has been reported to be around 12.57% (Sharma et al., 2015) and was reported to be associated with the following features: narrow maxillary arch with Jabially inclined maxillary incisors, increased overjet and compromised facial aesthetics and function (Bishara, 2006). Given the larger prevalence of this malocclusion, multiple treatment protocols, including orthodontic camouflage and distalization methods have been reported in the literature.
However, a shift to non-extraction treatment protocol has largely been governed by the transition to the face-driven soft tissue paradigm concept (William Arnett and McLaughlin, 2004).
The modified envelope of discrepancy, originally given by Profitt and Ackerman, was an expression of the millimetric range of treatment possibilities in anteroposterior, vertical, and transverse dimensions (Ackerman, Proffit and Sarver, 1999), now incorporates extent of tooth movement with temporary anchorage devices (TADs). With the introduction of TADs in orthodontics, it has been possible to increase the range of motion of teeth movement along all three dimensions (Graber and Swain, 1985 and Choi, 2020). Amongst the extra-alveolar TAD placement locations in the maxilla; Infrazygomatic crest (IZC) and palate regions are of notable mention. Skeletal anchorage devices have seen a wide array of clinical implications, especially to treat borderline surgical cases or the one, where it warrants extraction of teeth by camouflage which patients are unwilling for (Park, 2020). Extra alveolar placement of TAD's, distant to the teeth roots, generally have a higher bone density, and renders primary stability of the miniscrews (MS), thereby increasing treatment range of orthodontic teeth movement (Wilmes et al., 2006). Common anatomical locations for extra alveolar placement of mini screws include the infrazygomatic crest (IZC) region and the palatal region in the maxilla (Matias et al., 2021). One of the most common extra-alveolar sites for TAD placement is the infrazygomatic crest region, proposed originally by Liou et al (Liou et al., 2007), which is a reinforced buccal bone with thicker cortical bone, and clinically palpable as a bony protuberance located anteriorly to the maxillary tuberosity. The main advantage reported is that IZC offers immediate loading of forces in the magnitude of 220-340 g, and can be used in various clinical scenarios (Park, 2020). In a recent prospective study by Rosa et al that investigated the treatment effects of total maxillary arch distalization using IZC miniscrews, it was reported that average time for Class II correction ranged from 7.7 + 2.5 months, with average 4mm distalization, 1.2 mm first molar intrusion with 11.20 molar tipping. These studies indicate that the placement of miniscrews on the infrazygomatic crest as an

absolute anchorage for maxillary molar distalization, however, unfortunately, there may not be a force vector parallel to the occlusal plane biomechanically, and may sometimes cause irritation at the movable vestibular mucosa and buccal cheek mucosa. Therefore, the placement of infra-zygomatic crest (IZC) mini screw comes with a lot of disadvantages which includes insufficient cortical bone thickness for IZC; maxillary sinus perforation and soft tissue inflammation around IZC.
The median and paramedian areas of the palate consist of thick cortical bone that offers enough bone quality and quantity to support these mini-implants. Moreover, the median and paramedian areas of the palate has the advantages of having no significant anatomical structures, which can interfere with the placement of mini-implants. Additionally, availability of extra alveolar site, thin soft tissue, keratinized gingiva, lesser propensity to damage neurovascular bundle and closer to the center of resistance (CRes) of maxillary, which is reported to allow a wide range of biomechanically sound teeth movement and greater molar distalization and better vertical control.
In a study to investigate the treatment effects with Modified C-Palatal Plate (MCPP), which is commercially available, on 46 adult Class II patients, Kook et al reported a mean distalization time of 10.6 months with 3.7mm and-3r30 mean distalization and distal tipping of the maxillary first molar and mean 2mm retraction of both upper and lower lip (Kook et al., 2014).
In a recent study comparing MCPP to buccal miniscrews in molar distalization, it was found that MCPP reported far greater molar distalization (4.2mm) and 1.6mm intrusion of first molars with 2° distal tipping. The miniscrew group showed 2 mm distalization with 7.2° distal tipping and almost no intrusion (Lee et al., 2018).
Although commercially available modified C-palatal plate (MCPP) was successfully used for molar distalization in both adolescents and adults, the soft tissue impingement and inflammation were the major drawbacks reported (Kook, Kim and Chung, 2010). Since then, design modifications including screw tubes to prevent gingival overgrowth and custom placement jig for installation of MCPP have been introduced. Various design modifications reported in the literature include, 1) screw tubes to encounter the micro-movements of the plate under the distalization forces, especially the torquing element and provide a plate-bone contact, thereby reducing the possibility of inducing inflammation on the soft tissue around MCPP. 2) Posterior angulated (distally curved) arms to provide a longer range of action 3) Modified hooks (notches) to prevent easy disengagement or slippage of traction elastics/elastomeric chains and to provide an intrusive component for the posterior teeth by differential engagement of the traction elastics 4) Custom placement jig (Kook, Kim and Chung, 2010; Park, Park and Kook, 2023). A recent study, utilizing both the VAS and the Wong-Baker Faces Pain Rating Scale, was conducted to record patients' self-reported pain perception following mini-implant placement. The study concluded that the highest level of pain was reported in cases involving palatal mini-implants (Sreenivasagan et al.t 2021). This was correlated with a higher miniscrew placement torque attributed to the dense palatal cortical bone, leading to higher pain levels immediately post miniscrew placement. Pertaining to the speech assessment with the MCPP appliance, a recent study evaluated the speech perturbation and adaptation with the MCPP appliance and reported that MCPP caused temporary speech alteration in some patients. However, speech adaptation to MCPP appliances occurred within 1-2 weeks.
Therefore, there remains a need in the art to provide a modified palatal plate design, to circumvent the aforementioned drawbacks such as soft tissue impingement and inflammation, speech

perturbation, patient discomfort as well as to reduce degree of skeletal and dental relapse over time.
Also there remains a need in the art to provide a novel, patient-specific customized palatal plate for en masse maxillary arch distalization.

Objectives of the present invention: Therefore, it is a primary objective of the present invention to provide patient-specific customized palatal plate design, for en masse maxillary arch distalization.
Another objective of the invention is to provide a method for fabrication of patient-specific customized palatal plate design, for en masse maxillary arch distalization. Another objective of the present invention is to evaluate and compare the patient comfort factors of maxillary molar distalization using patient-specific customized H palatal plate {HPP- Group 1) and infrazygomatic mini-implants (IZC- Group 2) in adult patients with Class II Div 1 malocclusion.
A further objective of the invention is to evaluate and compare 1) Pain perception; 2) Patient comfort factors in the HPP- Group 1 and IZC- Group 2.

Summary of the invention: In line with the above objective, the present invention provides patient-specific customized H palatal plate design for en masse maxillary molar distalization, in adult patients with Class II Div 1 malocclusion and a method for fabrication thereof.
The patient-specific customized H palatal plate of the present invention provides higher accuracy, better site adaptation, enhanced stability, precise control over tooth movement, accurate repositioning of jaws, less chairside time.
In another aspect, the palatal plate of the invention comes with varied dimensions of palatal vault to meet the requirement of varied cortical bone thickness and palatal contour, specific to each patient.

Description of drawings: Figure 1 depicts the design of H-Palatal plate Figure 2 depicts HPP, designed on OrthoAnalyzer 3Shape software Figure 3 depicts HPP with the custom placement jig Figure 4 depicts clinical picture post HPP placement with distal traction forces delivered with elastomeric chains from the palatal retraction arch Figure 5 depicts the questionnaire to assess the patient comfort factors

Detailed description of the invention: The invention will now be described in detail in connection with certain preferred and optional embodiments so that various aspects thereof may be more fully understood and appreciated.
Abbreviations: IZC miniscrews: infrazygomatic miniscrew TADs: Temporary anchorage device MCPP: Modified C-Palatal plate HPP: H-Palatal plate
The present invention provides patient-specific customized palatal plate for en masse maxillary arch distalization, in adult patients with Class II Div 1 malocclusion.
It is noteworthy that the'thickness of palatal soft tissues may influence an orthodontists decision on the length of mini-implants for its stability and overall success and therefore, it is important that both palatal hard and soft tissue thickness should be considered in the planning of palatal mini­implant insertion.
Accordingly, in an embodiment, the present invention provides patient-specific customized palatal plate design, herein after referred as HPP (H-Palatal plate) design (figure 1), as an oral appliance that uses miniscrews to efficiently distalize molars minimizing the need for extraction.
In accordance with the invention, the patient-specific customized H palatal plate (HPP) must extend in the area between the maxillary first molar-second premolar as shown in figure 2.
According to a preferred embodiment, the patient-specific customized H palatal plate (HPP), for en masse maxillary arch distalization, is characterized by; a) a central assembly consisting of three screw tubes, one anterior (to be placed between the first and second premolar), and two posterior (to be placed between the second premolar-first molar) connected by a major connector, the palatal bar, to secure the device to the palatal area, wherein, the two posterior holes are more lateral (3 to 4 mm) to the midpalatal suture; and b) distally curved lever arms having three hooks/notches originated from ends of the palatal bar bilaterally at the region of the first maxillary molar and extend until the second molar, to improve the force control vector and to engage the elastomeric chains for traction.
In one of the preferred embodiments, the screw tubes are of dimensions (2.3 mm inner diameter, 3 mm outer diameter, height x widths 2x2mm) connected by a major connector, the palatal bar of dimensions (2x10mm).
In one of the preferred embodiments, the distally curved lever arms are of dimensions (2x10mm) that originate from ends of the palatal bar bilaterally at the region of the first maxillary molar and extend until the second molar.

In one of the preferred embodiments, the lever' arms are 1 to 2 mm away from the palatal mucosa to avoid soft tissue impingement and overgrowth.
In one of the preferred embodiments, the H palatal plate is preferably made using cobalt-chromium base metal.
In another preferred embodiment, the H palatal plate of the invention is customized and is patient­specific to cater and adapt to the varied dimensions of the palatal vault, characteristic to each individual to meet the requirement of cortical bone thickness in each patient. Accordingly, the H palatal plate can be custom designed to fit the varied palatal contour and morphology of the palatal vault.
In another preferred embodiment, palatal bone mapping was done using the CBCT scans of each patient and safe anatomic zones for miniscrew placement was mapped. The safe sites for palatal miniscrew placement were determined to be around 3-4 mm away from the midpalatal suture, with average palatal bone thickness ranging from 5.55-6.83 mm. The miniscrew must be placed perpendicular to the palatal surface and angled towards the incisor root for optimum retention and stability. Post leveling and aligning, alginate impressions with the maxillary first molar bands were taken and maxillary casts were poured using dental stone for the fabrication of assembly of distalization appliance (HPP)mentioned above. The intraoral scans post leveling and aligning were taken using the 3Shape TRIOS 3 scanner, saved in the Stereolithographic (STL) file format and exported into the 3Shape designing software for the designing of the custom HPP.
Accordingly, a method for fabrication of patient-specific customized H palatal plate (HPP), for en masse maxillary arch distalization, which comprises the steps of; a) Palatal bone mapping of a patient for safe anatomic zones for miniscrew placement using CBCT scans;
b) Determining the safe sites for palatal miniscrew placement, which is to be around 3-4 mm away from the midpalatal suture, with average palatal bone thickness ranging from 5.55-6.83 mm; c) Placing the miniscrew perpendicular to the palatal surface and angled towards the incisor root for optimum retention and stability; d) Post leveling and aligning, taking the alginate impressions with the maxillary first molar bands; e) Pouring maxillary casts using dental stone for the fabrication of assembly of distalization appliance; and
f) Performing intraoral scans of the patient post leveling and aligning using the 3Shape TRIOS 3 scanner, saving in the Stereolithographic (STL) file format and exporting into OrthoAnalyzer 3Shape software for 3D metal printing in DICOM format to the EOS M 100 3D metal printer in the base metal Cobalt- Chromium (Cr-Co) by DMLS technology.
The HPP according to the present invention is digitally designed on the software, custom fit to adapt to the palatal contour and morphology, thereby offering better patient comfort and lesser propensity to cause temporary speech alterations.
From the cursory review of the literature, it is evident that patient-specific customized H palatal plate is hither to unreported, " and adapt to the varied dimensions of the palatal vault,

characteristic to each individual to meet the requirement of cortical bone thickness. Also, there is no study reported in the literature that facilitates direct comparison of the two extra-alveolar treatment modalities a) Modified Palatal plate; and b) buccal infrazygomatic miniscrew (IZC). Further, no randomized clinical trials exist in literature pertaining to comparative evaluation of treatment effects with palatal and buccal TAD assisted anchorage for molar distalization and en masse maxillary arch distalization.
Therefore, in another embodiment, the invention provides evaluation and comparison of the dental and skeletal effects of maxillary molar distalization, using the patient-specific customized H palatal plate (HPP- Group 1) and existing infrazygomatic mini-implants (IZC- Group 2) in adult patients with Class II Div 1 malocclusion.
Accordingly, a randomized prospective trial (study design) was carried out in an institutional setting on patients who reported to the Department of Orthodontics and Dentofacial Orthopedics with their informed consent. Adult patients (>17 years of age), with Class II Division 1 malocclusion with a full cusp Class II molar relation or half cusp (end on) molar relation on either side, requiring bilateral en masse maxillary arch distalization, aided with either Infrazygomatic Crest (IZC) miniscrews or with H- Palatal Plate. The study was approved by the Institutional Review Board and Human Ethical Committee of Saveetha Dental College, SIMATS University and was granted Ethical Clearance Number (IHEC)- IHEC/SDC/ORTHO-2104/22/TH-057. This trial was registered in the Clinical Trials Registry-lndia (CTRI) and was granted the registration number- CTRI/2023/08/056058.
A priori test with alpha error at 0.05 and power of 0.90 was used for sample size estimation with G power analysis (G* power version 3.0.10, Kiel, Germany), based on a previous study published by Rosa et al (Rosa et al., 2023). The sample size was estimated at n=8/group, and keeping an attrition rate of 20%, was determined to be N= 10/group.
The screening and selection of participants was done by strictly adhering to the inclusion and exclusion criteria. The inclusion criteria were based on the following parameters like, subjects with Class II division 1 malocclusion requiring en masse distalization, Age 18-35 years, Full cusp or half cusp Class II molar relation, Overjet > 6 mm, No systemic illness, absence of bone metabolic disorders, Periodontally healthy subjects with a healthy condyle-fossa relationship, healthy condyle relationship and Orthognathic mandible +/- mild chin retrusion. The exclusion criteria were based on the following parameters like patients not willing to participate in the study, Patients with a history of anemia, vascular diseases, Patients with history of smoking and Patients on long term use of corticosteroids, bisphosphonate therapy and NSAIDs.
Randomization was employed by a simple coin toss method. Patient willingness to participate in the trial was obtained prior to their enrollment and allocation to their respective groups. The patients were informed regarding their involvement in the study. The patients received comprehensive explanations about the study's purpose, the treatments administered, the follow-up period, and any potential risks or benefits. Patients were also informed that they could opt out of the study at any time without it negatively affecting their need to receive the necessary treatment. The "CONSORT" guidelines were followed at every stage of the clinical trial, including reporting.
According to the invention, a randomized controlled trial was conducted employing Class II Division 1 subjects (divided into two groups, each consisting of 10 subjects) requiring bilateral en masse maxillary arch distalization. The subjects requiring bilateral en masse maxillary arch distalization



were treated using either H-Palatal Plate-Group I or IZC miniscrews-Group II, following extraction of upper third molars. The preoperative records were taken before bonding with metal MBT prescription with 0.22" slot (AO Mini Pre-adjusted Edgewise, USA). Leveling aligning was done until 0.019x0.025 Stainless Steel (SS) wire was passive in the bracket slots. Extraction of maxillary third molars was performed at least two months before starting en masse distalization.
In a preferred embodiment, the IZC miniscrew insertion in Group-ll was carried out utilizing 2x12 mm IZC miniscrew manufactured by Favanchor TMSAS, India. Distalizing traction forces were initiated by extending elastomeric chains from the anterior crimped hooks between the lateral incisor and canine regions, administering force levels ranging from 250- 300g per side. Palatal bone mapping in the Group-I subjects was conducted using CBCT scans to identify safe anatomical zones for miniscrew placement, located 3-4 mm away from the midpalatal suture, with an average bone thickness of 5.55-6.83 mm. Intraoral scans of the subjects post leveling and aligning were obtained using the 3Shape TRIOS 3 scanner and exported for custom HPP design, which was 3D printed in Cobalt-Chromium base metal using DMLS technology. Bilateral greater palatine nerve block and local anesthesia were administered before inserting HPP using self-drilling Medusa implants (2x10mm dimensions, Favanchor, TMSAS) with the L'il One Small Hand driver. Distalization traction forces were immediately initiated with elastomeric chains (250-300g/side) after HPP placement.
The present invention further provides comparative study using H-palatal plate (palatal anchorage) Vs IZC miniscrews (buccal anchorage), for the assessment of skeletal, dental effects and patient comfort factors during en masse maxillary arch distalization in both the study groups for 5 months.
Each group consists 10 subjects. The results from pre and post 5-month time points between intervention groups revealed a significant decline (p value= 0.026) in the mean SNA angle in the HPP group (1.690 +/- 0.83 mm) compared to the IZC miniscrew group (-0.223 +/- 2.34 mm). The mean changes in other skeletal parameters were not significantly different between the study groups (p value>0.05). Amongst the dental parameters that were evaluated,.there was a significant amount of extrusion of maxillary incisors and second molar (p= 0.009 and p=0.014, respectively). The maxillary second molar and incisors showed significantly greater amount of distal tipping in 3 months duration in the IZC miniscrew group (-5.39±4.37") compared to the HPP group (-1.31+2.78°).
The outcome of this study showed greater distalization of maxillary second molar and decrease in SNA angle with group I (HPP) with lesser amount of distal tipping in comparison to greater molar and incisor extrusion and distal tipping with group II (IZC).
Thus, the present invention conclusively established that the H-Palatal Plate resulted in notably increased distalization of the maxillary second molar, accompanied by a reduction in the SNA angle.
Furthermore, there was a significant decrease in both maxillary molar and incisor extrusion, as well as diminished distal tipping thereby proving to be more biomechanically advantageous when compared to buccal IZC miniscrew anchorage. Moreover, there was no significant difference in the skeletal parameters between the groups, given the follow up period of five months. Therefore, the results from this clinical trial established the superiority of the HPP of the present invention involved in an efficient non-extraction method for distalizing the maxillary dentition, with a relatively true translation movement of maxillary first and second molars with lesser distal tipping.
Moreover, the assessment of pain levels and patient discomfort between the two groups revealed no statistically significant difference, however a slightly lesser incidence of staying away from work,
speech and swallowing impediment was noted in the IZC miniscrew group, thereby further establishing the superiority of the HPP of the present invention.
Thus, the custom, patient-specific 3D printed HPP placed with the help of a custom placement jig of the present invention, offers various advantages like higher accuracy and precision for miniscrew placement, better site adaptation, enhanced stability of the miniscrew, precise control over tooth movement, accurate repositioning of jaws and lesser operator-chairside time, when compared to the IZC miniscrew anchorage.
Therefore, the prospective avenue entails evaluating the application of HPP to expedite orthodontic tooth movement, encompassing a broader participant pool and extended monitoring periods, while also considering the long-term stability of treatment outcome to ensure more definitive outcomes.
Those of ordinary skilled in the art will appreciate that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments or examples disclosed herein but is intended to cover modifications within the objectives and scope of the present invention as defined in the specification.
The examples are given solely for illustration and are not to be construed as limitations of the present disclosure, as many variations thereof possible without departing from the spirit of the disclosure.

Examples: Example 1: Infrazygomatic Crest Implants The IZC miniscrew placement was done as recommended by Liou et al (Liou et al., 2007), that is in line with the mesiobuccal cusp of the maxillary first molar, about 12-16mm above the maxillary occlusal plane at an angle of 40-700 using the IZC miniscrew (2x12 mm) by Favanchor TMSAS, India.
The distalizing traction forces were initiated by stretching elastomeric chains from the anterior crimped hooks in the region of lateral incisor-canine, delivering force levels of 250-300g/side as determined by the Dontrix gauge Dynamometer (GDC Fine Crafted Dental Pvt. Ltd, India).
Example 2: Design of the H-Palatal Plate: The HPP (Figure 1) was designed to extend in the area between the maxillary first molar-second premolar. It consists of a central assembly of three screw tubes, one anterior (between the first and second premolar), and two posterior (between the second premolar-first molar) of dimensions (2.3 mm inner diameter, 3 mm outer diameter, height x width= 2x2mm) connected by a major connector, the palatal bar of dimensions (2x10mm), which is bilaterally extended with curved lever arms. The distally curved lever arms of dimensions (2x10mm) originated from ends of the palatal bar bilaterally at the region of the first maxillary molar and extend until the second molar. These lever arms have three hooks/notches to improve the force control vector and to engage the elastomeric chains for traction. The lever arms are 1-2 mm away from the palatal mucosa to avoid soft tissue impingement and overgrowth.

The HPP, as above was designed on OrthoAnalyzer 3Shape software (figure 2) and exported for 3D metal printing in DICOM format to the EOS M 100 3D metal printer in the base metal Cobalt- Chromium (Cr-Co) by DMLS technology. Once received post printing, the plates were finished using TC Cross Cutter Superfine Tungsten Carbide Bur, TC Round Bur (0.1mm), TC Cross Cutter Standard Bur. The final polishing was achieved with cotton and rubber polishing wheels with universal polishing paste attached to the Marathon M4 Lab Micromotor.


Example 3: Assembly of distalization appliance (HPP): The steps involved in the assembly of distalization appliance (HPP), are as follows. 1. Extraction of maxillary third molars were performed at least two months prior to the commencement of distalization. 2. Fabrication of Palatal Retraction Arch (PRA)- The PRA, running anteriorly until the anterior palatal mucosa of the anterior teeth, was made from a rigid 19-gauge stainless steel wire welded on to the maxillary first molar bands bilaterally, in an attempt to control the mesial tipping of the first molars.
Two hooks were soldered at the palatal region of maxillary lateral incisor-canine region bilaterally, for the engagement of the distalizing traction forces. 3. Custom Fabrication Jig {figure 3)- The 3D metal printed HPPs were adjusted according to the design specifications over the maxillary cast and secured lightly in place using Feviquick. The custom jig was fabricated by thermoforming 120 mm Duran sheets (made from Pet-G material) over the maxillary models using the Scheu Bio star Thermoforming unit. The jig was retrieved from the cast and cut along the extent over the HPP over the maxillary posterior teeth. It was further pre-sliced diagonally to facilitate the removal of the jig after the HPP placement. The jig was sterilized in Glutaraldehyde for 30 mins prior to in vivo placement of the HPP.

Bilateral greater palatine nerve block and local anesthesia was administered at the site of the implant placement, before the placement of the jig-HPP assembly. Ensuring that the jig fits the occlusal surfaces of the molars and premolars, self-drilling Medusa implants of 2x10mm dimensions (Favanchor, Skeletal Anchorage System, India) were inserted into the screw tubes using the L'il One Small Hand driver {Favanchor, Skeletal Anchorage System, India). After the HPP placement, the jig was retrieved using the utility pliers. Following the removal of custom jigs, it was deemed necessary to adjust or tighten the palatal miniscrews. Immediate loading and initiation of distalization traction forces with elastomeric chains (E-chain) of 250-300g/side was initiated and completed (Figure 4). All the patients were reviewed after one week for implant stability and to address their discomfort and concerns.

Data were analyzed using IBM SPSS version 20 software {IBM SPSS, IBM Corp., Armonk, NY, USA).
Normality of the data was assessed using the Shapiro Wilks test. Independent samples T tests and Chi Square tests were undertaken to analyze the study data. Descriptive statistics was used to understand the age and gender distribution among the study subjects. Independent samples T test was employed to assess the and VAS and FACES pain score between the two study groups (Group I- HPP and Group II- IZC miniscrew). The internal consistency reliability (Cronbach's alpha) was employed to assess the reliability of the questionnaire. Chi square test was used to compare the other patient comfort factors from the questionnaire- like the incidence of days staying away from work, disturbed sleep and the usage of analgesic between the groups. A p value of less than 0.05 was considered as significant.

We claim,
28^0ct-2O24/130613/202441082039/Form 2(Title Page)
1. A patient-specific customized palatal plate (HPP), as shown in figure 1, for en masse maxillary arch distalization, which is characterized by; a) a central assembly consisting of three screw tubes, one anterior (to be placed between the first and second premolar), and two posterior (to be placed between the second premolar-first molar) connected by a major connector, the palatal bar, to secure the device to the palatal area, wherein, the two posterior holes are more lateral (3 to 4 mm) to the midpalatal suture; and b) distally curved lever arms having three hooks/notches originated from ends of the palatal bar bilaterally at the region of the first maxillary molar and extend until the second molar, to improve the force control vector and to engage the elastomeric chains for traction. 2. The H palatal plate as claimed in claim 1, wherein, the screw tubes are of dimensions (2.3 mm inner diameter, 3 mm outer diameter, height x width= 2x2mm) connected by a major connector, the palatal bar of dimensions (2x10mm). 3. -The H. palatal plate as claimed in .claim l,_wherein, the distally curved lever arms are of dimensions (2x10mm) that originate from ends of the palatal bar bilaterally at the region of the first maxillary molar and extend until the second molar. 4. The H palatal plate as claimed in claim 1, wherein, the lever arms are 1 to 2 mm away from the palatal mucosa to avoid soft tissue impingement and overgrowth. 5. The H palatal plate as claimed in claim 1, wherein, the H palatal plate is custom designed to fit the varied palatal contour and morphology of the palatal vault. 6. The H palatal plate as claimed in claim 1, wherein, the H palatal plate is preferably made using cobalt-chromium base metal. 7. The HPP as claimed in claim 1, is digitally designed on the software, custom fit to adapt to the palatal contour and morphology, thereby offering better patient comfort and lesser propensity to cause temporary speech alterations. 8. A method for fabrication of patient-specific customized H palatal plate (HPP), for en masse maxillary arch distalization, which comprises the steps of; a) Palatal bone mapping of a patient for safe anatomic zones for mini screw placement using CBCT scans;
b) Determining the safe sites for palatal miniscrew placement, which is to be around 3-4 mm away from the midpalatal suture, with average palatal bone thickness ranging from 5.55-6.83 mm; c) Placing the mini screw perpendicular to the palatal surface and angled towards the incisor root for optimum retention and stability; d) Post leveling and aligning, taking the alginate impressions with the maxillary first molar bands;
e) Pouring maxillary casts using dental stone for the fabrication of assembly of distalization appliance; and
Performing intraoral scans of the patient post leveling and aligning using the 3Shape TRIOS 3 scanner, saving in the Stereolithographic {STL) file format and exporting into Ortho Analyzer 3Shape software for 3D metal printing in DICOM format to the EOS M 100 3D metal printer in the base metal Cobalt- Chromium (Cr-Co) by DMLS technology.

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