SUCCESS RATE OF DIFFERENT MICRO IMPLANT SYSTEMS

Abstract

This present study was conducted to compare the stability of 3 different microimplant systems with different costs, over a period of 6 months. In 16 adult patients (7 males, 9 females; mean age, 19.81 years), a total number of 32 micro-implants (1.3-1.4 mm in diameter and 8 mm long) were placed between the roots of maxillary 2nd premolar and the first molar. A new system was used to classify microimplant failure on the upper left and right quadrant during a specified period of 6 months. The overall success rate was 78.1%, a value suggesting that microimplants of S.K. surgicals are as stable as those of Denticon and Absoanchor (Dentos), and can be applied as cost-effective substitutes. When inserted between the roots of maxillary second premolar and first molar by a self-drilling, incision-free method, cost-effective microimplants appeared as stable as their more expensive counterparts. Female patients recorded a higher success rate than males, and the maxillary left quadrant had more success than the right quadrant.

Headnote

Abstract

Introduction: The present study was conducted to compare the stability of 3 different microimplant systems with different costs, over a period of 6 months. Methods: In 16 adult patients (7 males, 9 females; mean age, 19.81 years), a total number of 32 micro-implants (1.3-1.4 mm in diameter and 8 mm long) were placed between the roots of maxillary 2nd premolar and the first molar. A new system was used to classify microimplant failure on the upper left and right quadrant during a specified period of 6 months. Results: The overall success rate was 78.1%, a value suggesting that microimplants of S.K. surgicals are as stable as those of Denticon and Absoanchor (Dentos), and can be applied as cost-effective substitutes. Conclusions: When inserted between the roots of maxillary second premolar and first molar by a self-drilling, incision-free method, cost-effective microimplants appeared as stable as their more expensive counterparts. Female patients recorded a higher success rate than males, and the maxillary left quadrant had more success than the right quadrant. Orthodontic microimplant failure can be classified as: Grade I - Inflammation associated with the microimplant, Grade II - Mobility associated with the microimplant, Grade III - Change in microimplant angulation, Grade IV - Complete luxation of the microimplant. Microimplant fracture during its removal can be considered as a Grade V microimplant failure.

Keywords: microimplant, failure, stability

1. INTRODUCTION

A major problem in orthodontics and facial orthopaedics is anchorage control, undesirable movement of anchorage unit restricting the therapeutical range of biomechanics. Treating orthodontic patients with no anchor loss is the dream of every orthodontist. Traditionally, the anchor problem was solved by reinforcing the anchor tooth with appliances like Headgear, TP A, banding second molars, Nance Palatal Button, anchorage devices [1] (TAD's) temporarily placed near the bone, for enhancing or overcoming the limitations of traditional anchorage methods, which opened new horizons for the management of asymmetry, mutilated dentition and severe malocclusions. A TAD can be located transosteallv, subperiosteally or endosteally and can be fixed to the bone either mechanically (cortically-stabilized) or biochemically (osseo-integrated). However, the possible risks and complications [2] associated with these orthodontic implants during the treatment should be considered. Failure may occur in the form of adjacent tooth root damage, bone and soft tissue infections, lack of primary stability after insertion, change in axial inclination of the loaded implant, unscrewing and avulsion of the implant itself.

The purpose of the study was to compare 3 different microimplant systems of different costs on the basis of their stability, using a new classification system of microimplant failure over a specified period of six months.

2. MATERIALS AND METHOD

The study was developed on patients from the Department of Orthodontics, Pacific Dental College, Udaipur, India. The sample group consisted of 16 patients (7 males, 9 females; mean age: 19.81 years; SD: 3.5 years). The orthodontic treatment included extraction of maxillary 1st premolar, while mandibular 1st premolar extraction was optional, as the temporary anchorage devices were to be placed in the maxilla only between the roots of 2nd premolar and 1st molar. All patients were treated with a preadjusted edgewise appliance system (M.B.T.). The experimental sample was further divided into Group A and Group B, each one formed of 8 patients. The subjects were explained the advantages and drawbacks of the procedure. Informed consent of all 16 patients was taken, after which the microimplants were placed under strict aseptic conditions. Microimplants produced by 3 different manufacturers and with different costs were used (Fig.l), namely: 8 Ml (Absoanchor, Dentos, Daegu, Korea), 8M2 (Denticon, India) and 16 M3, (S.K. Surgicals India). All microimplants were 1.3 or 1.4 mm long and 8 mm in diameter.

In both Group A and B, S.K. surgical microimplants (India) were placed in the upper left quadrant between the roots of 2nd premolar and 1st molar. In Group A, microimplants of Denticon (India) were placed in the upper right quadrant between the roots of 2nd premolar and 1st molar. Similarly, in Group B, microimplants of Absoanchor, Dentos were placed in the upper right quadrant between the roots of 2nd premolar and 1st molar. The surgical procedure included a self drilling-incision free method, applid after making a punch marking on the attached gingival. The exact site on the attached gingiva was located with a 26 gauge stainless steel wire placed between the maxillary 2nd premolar and the 1st molar tooth, followed by IOPA (intraoral periapical) radiography, using a tube shift technique. The wire was retained during microimplant insertion and removed after its successful anchorage (Fig 2). This method reduces possible root damage.

The microimplants were immediately loaded (as the microimplant holds itself into the bone by mechanical stability) with static forces of 140-150 grs per side (measured with dontix gauge), using closed Ni-Ti coil springs for anterior complete retraction (Fig 3). Observations were made every month, along a 6 month period. Stability of microimplants was checked using a cotton tweezer.

Orthodontic microimplant failure can be classified as:

Grade I - Inflammation associated with the microimplant

Grade II - Mobility associated with the microimplant

Grade III - Angulation change of the microimplant

Grade IV - Complete luxation of the microimplant

Microimplant fracture during its removal can be considered as Grade V microimplant failure.

3. RESULTS

The results of the study evidenced the following failures: 7 microimplants in Groups A and B (success rate = 78.1%), namely 4 microimplants in Group A (success rate = 75%) and 3 microimplants in Group B (success rate = 81.2%). (Table 1)

The microimplant got completely luxated in Group A, while Group B recorded simultaneous values of 2 and 1 (Table 2).

Overall, 6 microimplant failures were noted in 7 males (success rate = 57.1%) and 1 microimplant failure was noted in 9 females (success rate = 94.4%). (Table 3)

In Group A, 2 microimplants of S.K. surgicals (success rate = 75%) and 2 microimplant of Denticon failed (success rate = 75%). In Group B, 1 microimplant of S.K. surgicals (success rate = 87.5%) and 2 microimplants of Dentos failed (success rate = 75%). Overall, 3/16 microimplants of S.K. surgicals (success rate = 81.2%) and 4/16 microimplants of Denticon and Ahsoanchor failed (success rate = 75%). (Table 4)

4. DISCUSSION

When using the Preadjusted Edgewise Appliance (M.B.T system), the orthodontist can overcome the major limitations associated with earlier appliances. The major advantages obtained include improved aesthetics, reduced overall treatment and shorter time in the dental chair. Moreover, microimplants associated with high success rates [3,4] permit various tooth movements, correction of various malocclusions and further reduction of the overall treatment time [5-10], without anchor loss [11], even if higher costs are involved.

The microimplants used in the present study wer produced by 3 different manufacturers:

1) S.K. surgicals, Pune, India - Indian microimplants, 250-00 Rupees (Indian Currency) per implant.

2) Denticon, India - Indian microimplants, 500-00 Rupees (Indian currency) per implant.

3) Ahsoanchor (Dentos) Korea - Korean microimplants, 1,700 Rupees (Indian Currency) per implant.

All microimplants (1.3 or 1.4 mm in diameter and 8.0 mm long) were inserted by the selfdrilling, incision-free method. No post-operative discomfort or complications [11] appeared in any of the patients, any only rarely medication was required. Kuroda et al. [4] also concluded that microimplants placed without a muco-periosteal incision or flap surgery significantly reduced patient pain and discomfort after implantation, while Kim et al. [12], who also compared the surgical techniques with and without drilling, found significantly higher hone-implant contacts with self-drilhng screws, associated with higher stability.

The microimplants of S.K. surgicals were expected to have a lower success rate than the other two materials, however the results obtained evidenced the opposite. In Group A, 2/8 microimplants of S.K. surgicals (success rate 75%) and 2/ 8 microimplants of Denticon failed (success rate 75% ) and in Group B, 1/8 microimplants of S.K. surgicals (success rate 87.5%) and 2/8 microimplants of Ahsoanchor failed (success rate 75% ). These results suggested that microimplants of S.K. surgicals were as stable as those of Denticon and Ahsoanchor (Dentos), being therefore recommended as cheaper substitutes in the maxillary left quadrant, between the roots of maxillary 2nd premolar and 1st molar. The here recorded success rates were very low, compared to those recorded in other studies [3,4,13], as microimplant failure was established according to our classification system of implant failure.

Park H.S. and et al. [3] also stated that inflammation can progressively damage the cortical hone and thus affect the stability of the microimplant. On the whole, 6/14 microimplant failures were noted in 7 males (success rate = 57.1 % ) and 1 /18 microimplant failures in 9 females (success rate = 94.4%). Other studies [3,4] confirm that females record a higher success rate than males. Overall, 3/16 microimplants of S.K. surgicals (success rate = 81.2%) and 4/16 microimplants of Denticon and Absoanchor failed (success rate = 75%), which suggested that the left side registers a higher success rate than the right side, as also mnetioned by. Park H.S. et al. [3]. All microimplants of S.K. surgicals were inserted on the left side, whereas all microimplants of Denticon were placed on the right side, which might explain the high overall success rate of S.K. surgicals microimplants, a situation still to he investigated in further studies.

5. CONCLUSIONS

S.K. surgicals microimplants (India) were as stable as the Denticon and Dentos (Absoanchor) ones. Globally, female patients recorded a higher success rate (94.4%) than males (57.1%). Also, a higher success rate was associated with the left side (81.2%) vs the right side (75%).

References

References

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