RAJIVGANDHIUNIVERSITYOFHEALTHSCIENCES,

BANGALORE,KARNATAKA

ANNEXURE –II

PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION

1 / NAME OF THE CANDIDATE
AND ADDRESS / Dr. GIRISH H CHHABRANI
POST GRADUATE STUDENT,
DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS ,
RAJARAJESWARI DENTAL COLLEGE AND HOSPITAL,MYSORE ROAD,
BANGALORE – 560060.
2 / NAME OF THE INSTITUTION / RAJARAJESWARI DENTAL COLLEGE
AND HOSPITAL
3 / COURSE OF STUDY AND SUBJECT / MASTER OF DENTAL SURGERY IN
ORTHODONTICS AND DENTOFACIAL
ORTHOPAEDICS
4 / DATE OF ADMISSION TO THE COLLEGE / 25th MAY 2012
5 / TITLE OF THE TOPIC:
“TORSIONAL FORCE AND ITS EFFECT ON MINISCREW IMPLANTS DEPENDING ON DIAMETER,LENGTH AND SHAPE OF IMPLANT – AN INVITRO STUDY.”
6
7. / BRIEFRESUME OF THE INTENDEDWORK:
6. 1NEED OF THE STUDY:
Anchorage control is an important factor for success in orthodontics.1In orthodontic treatment until now various techniques to reinforce anchorage has been devisedand miniscrew implant is one of them.1,2
Recently several kinds of implant anchor which provide absolute anchorage have attracted attention of orthodontists.3,4Among them titanium miniscrew implant have become popular because of lower cost,simple placement,simpler placement surgery,and less discomfort after implantation when compared with dental implants for abutment.1,2 On the other hand fracture of miniscrew implants have sometimes occurred during placement or removal.
The initial stability of a miniscrew is important but in most instances failure occurs at an early stage.3 Miniscrew implant factors such as implant diameter,length,pilot hole diameter,and thread design are also believed to be important for initialstability.The insertion torque is commonly used to evaluate the mechanical stability of implants which is also applicable for miniscrews implants.3
Many variables that affect the stability of orthodontic mini-implants (also called temporary anchorage devices) are still poorly understood.It has been suggested that excessive torque forces applied during the insertion of these devices can cause necrosis of the surrounding bone and compromise their success.5
It is therefore necessary to understand at what levels torque strains remain physiologic and canguarantee the stability of the implants.5 Even though orthodontic forces are not normally great enough to break the screw, the rotational forces associated with the placement and removal can cause miniscrew failure.4
AIMSANDOBJECTIVESOFTHESTUDY:
The purpose of study is to investigate the torsional force with respect to diameter, length and shape of commercially available titanium miniscrew implants.
6.2REVIEWOFLITERATURE:
  1. Seon-A Lim, Jung-Yul Cha, Chung-Ju Hwang3 conducted a study to determine the variation in the insertion torque of orthodontic mini screws based on the length,diameter and shape.The maximum insertion torque (MIT) was measured using a torque tester at a constant speed of 3 rotations per minute.Cylindrical and taper type of miniscrews with different lengths,diameter and pitches were tested. They concluded that screw diameter can efficiently reinforce the initial stability of miniscrew.
  2. Aldo Carno,Stefano Velo,Paola Leone, GueseppeSiciliani4 performed a study to test torsion to failure using a tapped brass block at a thread depth of 6mm and a dial torque wrench with a recording device.They concluded that miniscrews can resist a force much greater than orthodontic application.However it is possible to apply a torsional force of more than 40ncm during insertion and removal and cause fracture.
  3. Masahiro Lijimaet al1, conducted a study were 4 brands of miniscrew implants with 1.6mm diameter were compared.Group A and C comprised of pure titanium, B and D comprised of titanium alloys.The miniscrews were loaded to failure in torsion and mean moment and twist angle were determined for each group.They concluded that addition of small amounts of other elements yielded significantly improved torsional performance for miniscrew implants.
  4. CesareLuzi,Calalberta Verna,BirteMelsen2 conducted a study which comprised of miniscrew implants of length 9.6mm or 11.6mm and a diameter of 1.5 or 2mm were used in all patients.The overall implants success rate was 91%.They concluded that incorrect insertion technique had been identified as primary cause of failure.Also inadequate irrigation,excessive drill speed,wiggling movements of screw driver and insufficient placement of torque are the most common mistakes.
  5. ReintA.Meursinge, Reynders,Laura,Ronchi,Luisa,Ladu,Faridi van Etten-Jamaludin and ShandraBipat5 conducted a study to analyze the success rate of orthodontic implants inserted with insertion torque values of 5-10ncm compared with the mini implants inserted with maximum torque values beyond third range.They concluded that no specific maximum insertion torque values are associated with higher success rate for orthodontic mini implants.Additional research on this topic is therefore necessary.
  6. Christian Wawrzinek, Dr.ThorstenSommer,Helge Fischer-Brandies6 conducted a study on three freshly prepared pelvic porcine bone segments and removed the periosteum, using a screwdriver.Later they manually inserted a total of 20 orthodontic microscrews. Five drill-holes were left empty,serving as a reference point. They concluded that over-tightened implants showed higher values in number of cracks,accumulated length of all cracks, in comparison to reference samples without screws.
  7. Eduardo Yugo SuZuki, BoonsivaSuZuki7 conducted a study to analyze the maximum insertion torque (MIT) and maximum removal torque (MRT) values of orthodontic miniscrews.Two hundred and eighty miniscrews were placed in several sites of maxillae and mandible.MIT and MRT values were assessed using a digital torque gauge.They concluded that relatively lower MIT values were more favorable to osseo-integration than higher value.
MATERIALS AND METHODS :
  1. The study sample consistsof titanium mini screw implants with Diameter- 1.3mm,1.4mm,1.5m and varying lengths - 6mm,8mm,and 10mm respectively.Based on thread shape, cylindrical and tapered titanium miniscrew implants will be selected.
  2. Torque testing machine
  3. A brass block of 12.8mm square and 25mm length
  4. Manual Implant driver
PROCEDURE:
  1. Titanium Miniscrew implants will be selected and grouped into 3 groups of varying diameter.
  2. They will be further subdivided into 3 groups of varying lengths of 6mm,8mm and 10mm.
  3. Titanium miniscrew based on thread shape, cylindrical and tapered will be selected.
  4. A torque testing machine,which willrecord the torque of titanium mini screw implant in Newton centimeters, will be selected for the study.For the placement, of titanium miniscrew implant, a brass blockwill be selectedin which predrilling will be done to a precise depth. This brass block will then be mounted on the torque testing machine.
  5. The titanium miniscrew implants will be placed with the help of implant driver, perpendicular to long axis of brass block and will be rotated in a clockwise direction until the implant fractures.
  6. When titanium miniscrew fractures,the torque will be recorded in torque testing machine.
  7. The recorded values will be compared for all groups and sub-groups of study sample of titanium miniscrew implants.
Recording of the data:
The values for the torque at the implant failure are noted for each implant in Newton centimeters.
Data Analysis:
The data will be compared using ANOVA test.
7.4 DOES THE STUDY REQUIRE ANY INVESTIGATION OR INTERVENTION TO BE CONDUCTED ON PATIENTS OR OTHER HUMANS, ANIMALS? IF SO PLEASE DESCRIBE BRIEFLY?
No
7.5 HASETHICAL CLEARANCE BEEN OBTAINED FROM YOUR INSTITUTION IN CASE OF 7.3?
Yes.
LIST OF REFERENCES :
  1. Masahiro Lijima et al.Torsional properties and microstructures of mini screw implants. Am J Orthod 2008;134:333.e1-133.e6
  2. CesareLuzi et al Guidelines for success in placement of orthodontic mini implants. J ClinOrthod 2009;18:39-44.
  3. Seon-A Lim,Jung-YulCha,Chung-Ju Hwang.Insertion torque of orthodontic miniscrews according to changes in shape, diameter and length. Angle Orthod 2008;78:234-40.
  4. Aldo Carno, StefanoVelo, Paola Leone,Guseppe Siciliani. Clinical application of mini screw anchorage system.JClinOrthod. 2005;39:9-23.
  5. ReintA.Meursinge et al. Insertion torque and success of orthodontic mini implant:A systemic review.Am J Orthod 2012;142:596-614.
  6. Christian Wawrzinek,Dr.Thorsten, Sommer,Helge Fischer-Brandies.Microdamage in cortical bone due to the over-tightening of orthodontic miniscrews.OrofacOrthop 2008;69:121-34.
  7. Eduardo Yugo Suzuki,BoonsivaSuzuki. Placement and removal torque values of orthodontic miniscrew implants. Am J Orthod 2011;139:669-78.

9 / SIGNATURE OF THE
CANDIDATE
10 /

REMARKS OF THE GUIDE

11 / 11.1 NAME & DESIGNATION
OFGUIDE / Dr. HEMALATHA SANJAY, M.D.S
PROFESSOR,
DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS,
RAJA RAJESWARI DENTAL COLLEGE AND HOSPITAL, BANGALORE.
11.2 SIGNATURE OF GUIDE
11.3 CO-GUIDE (If any)
11.4 SIGNATURE
11.5 HEAD OF THE
DEPARTMENT / Dr. RAJKUMAR S. ALLE, M.D.S, DNB
PROFESSOR AND HEAD,
DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS,
RAJA RAJESWARI DENTAL COLLEGE AND HOSPITAL, BANGALORE.
11.6 SIGNATURE
12 / 12.1 REMARKSOFTHE
CHAIRMAN & PRINCIPAL
12.2 SIGNATURE