2. Retrospective Clinical Study of a Freely
Removable Implant-Supported Fixed Dental
Prosthesis by a Microlocking System
Bae EB, Cho WT, Bae HY, Lee SH, Kim TH, Huh JB. Retrospective Clinical Study of a Freely
Removable Implant-Supported Fixed Dental Prosthesis by a Microlocking System. BioMed Research
International. 2020 Nov 3;2020.
3.
4. • Does not damage adjacent teeth and offers aesthetic and functional
advantages.
• Screw Retained or Cement Retained Systems
• The success rate of implant was not affected in either of the retained
types of implant prosthesis.
5. • Screw retained prosthesis-
Facilitates removal, repairs, and hygiene maintenances of the implant
prosthesis
Prevents complication arising due to residual cement.
× Unaesthetic and interfering occlusal contact points due to screw access
hole
× Screw loosening and fracture of prosthesis
6. • Cement retained prosthesis-
Easily achievable passive fit
Absence of access hole on occlusal surface
× Peri implant diseases due to excess leftover cement
7. • Screw-and-cement retained prosthesis (SCRP)-
Combines advantages of screw as well as cement retained prosthesis.
Restricted by an inappropriate screw access hole within the occlusal
surface.
8. • A micro-locking implant prosthetic system; EZ Crown by Samwon DMP
• It is a freely removable system using zirconia ball and Ni-Ti spring.
• Aesthetic, has occlusal stability, and passivity of prosthesis
• Can prevent the mechanical (e.g., screw loosening and fracture) and
biological complications( e.g., peri-implantitis)
9. • MLP studied here has completely different components which can lead
to previously unreported prosthetic complications.
• The present study investigated the periodontal indices and
complications in the cases using MLP through retrospective clinical
examination and radiological analysis.
10. The aim of this study was to to evaluate the clinical
usefulness and complications of the newly developed
Micro-locking prosthetic system.
11.
12. • Research Subjects-:
54 patients (31 male + 23 female) with total 100 implant prosthesis.
Evaluation done after minimum 6 months of prosthetic delivery
Patients above 20 years old with no systemic diseases included.
Patients unable to maintain regular follow up excluded.
13.
14. • Micro-locking Implant Prosthesis-
a. Body has several grooved hexagonal receptacles
b. Ball made up of Zirconium Oxide and Hafnium Oxide
c. Spring contains Nickel Titanium shape memory alloy
d. Cap easily positioned on undercut of retention groove
e. Retention Groove seen on the abutment
15. • Balls are seated in the retention groove so that they are directly
involved in the retention and prevent the rotation of the spring.
• Spring maintains a constant stress value, and retentive components are
restored even in large deformational distortion.
• Spring expands slightly when cap is engaged with the abutment thus
applying a constant external force to the ball.
16. • Abutment was tightened to 35Ncm and cap attached using a
dedicated tool.
• Impressions taken using silicone impression material and scanned
using 3D scanner (Trios 3shape)
• Crown evaluated for marginal fit, aesthetics and occlusion intra-orally.
• Excess cement of crown removed extra-orally and the crown with cap
was attached back to the abutment.
17. • Clinical Examination-:
A. 6-12 months, B. 12-18 months, C. 18-24 months
Clinical and radiographic examination done in comparison to placement.
Evaluation criteria included-
1. Persistent or no recurrence of infection around implant
2. No persistent discomfort
3. Absence of clinical mobility
4. No radiological bone loss around implant
Comparison done with image measurement programme (i-Solution, IMT)
18. • Probing depth measured at mesial, distal, buccal and lingual surfaces
around implant using periodontal probe (Merrit-b, Hu-Friedy)
• Modified plaque index checked according to Mombelli et al criteria
• Modified sulcus bleeding measured using periodontal probe
• Complications arising following prosthesis delivery were also recorded
and tabulated.
19. • Statistical Analysis-:
ANOVA with post-hoc Tukey’s test to compare marginal bone
resorption
Kruskal-Wallis test with post-hoc Mann Whitney U test used to
compare the probing depth
Bleeding index and Plaque index were compared by chi-square
test
Significance level for all was kept at 5%.
27. • Screw retained prosthesis may lead to screw loosening, screw fracture
or fracture of abutment.
• Cement retained type can lead to infection and marginal bone resorption.
• Excessive cement removal may damage the soft tissue around implant thus
leading to peri-implantitis
28. • It improves the problem of nonaesthetic elements and occlusal
contact formation.
• Freely attachable and detachable nature helps prevent excess cement
deposition
• Presence of zirconia ball and NiTi spring prevents adverse effects on
screw due to repeated attaching and detaching.
29. • Change in the retained structure of the implant prosthesis does not
significantly affect the implant survival rate within the initial 2 years.
• Marginal bone resorption according to previous studies-
Screw-retained= 0.4 ± 0.3 mm
Cement-retained= 0.3 ± 0.6 mm
• Marginal bone resorption around submerged and internal connection-
Screw-retained= 0.8 ± 0.8 mm
Cement-retained= 0.8 ± 0.4 mm
30. • Cement retained prostheses generally showed greater plaque
accumulation and bleeding than screw-retained prosthesis.
• Screw-retained prosthesis showed decreased plaque retention and
stable bleeding levels after six months.
• MLP also improved over time with mPI and mBI scores
31. • Main complications of cement retained and screw retained prosthesis
have been previously discussed.
screw loosening,
abutment loosening,
ceramic fracture,
loss of composite resin in the screw access hole,
abutment fracture
debonding of cemented crown
32. • The abutment loosening was a major complication of MLP and on
comparison was found to be higher than other systems
• There may have been a slight difference in the connection part of
fixture.
• Forming a micro-gap or incorrect joint between the connection part
of fixture and the abutment.
• The larger height of the abutment and the wider prosthetic table
width make the smaller lateral or rotational micromovement of the
33. • Failure to establish proper zirconia thickness, design problems, or
defects in the zirconia block itself.
• Implant prosthesis fracture is considered a common complication of
dental prosthesis, independent of implant abutment.
34. • Food impaction may occur by the loosening of the contact between
adjacent teeth.
• Load-bearing capacity of the MLP was not significantly different from
that of other commercially available systems.
35.
36. • Within the limitations of this study it was concluded that implant
prosthesis with Micro-locking Prosthetic system can be considered to
be an applicable and predictable treatment option. The study showed
a 2 year follow-up with 100% implant survival rate with no major
prosthetic complication other than screw loosening which has been
attributed to limited variety of abutment sizes.
37.
38. 1. Retrospective study does not allow to compare all factors
2. Short term follow-up period
3. Tool for removal and attachment of crown on cap not explained
4. Effect of implant angulations and use of abutment on multiple implants has not
been studied.
40. The load-bearing capacity of the micro-locking implant prosthetic system is
similar to that of other commercialized abutment systems, with change in
shape of retention groove having affect on the retention capacity. More study
on this new prosthetic system is needed to adopt it into clinical practise.
Choi JW, Choi KH, Chae HJ, Chae SK, Bae EB, Lee JJ, Lee SH, Jeong CM, Huh JB. Load-bearing capacity and
retention of newly developed micro-locking implant prosthetic system: An in vitro pilot study. Materials. 2018 Apr
6;11(4):564.
41. Kim MJ, Cho WT, Hwang SH, Bae JH, Bae EB, Shim JS, Kim JE, Jeong CM, Huh JB. A prospective multicenter clinical
study on the efficiency of detachable ball-and spring-retained implant prosthesis. The Journal of Advanced
Prosthodontics. 2023 Aug;15(4):202.
The BSRP group showed similar values of marginal bone loss, probing depth,
bleeding and plaque index as the SCRP. Screw loosening was frequently reported as
a complication. Thus the newly introduced detachable implant prosthesis utilizing a
zirconia ball and nitinol spring is shown to be an applicable and predictable
treatment method along with the existing SCRP.
Editor's Notes
The use of implants has gradually increased over the years due to its several advantages over the removable and bridge prosthesis like..
This has led to development of various types of implant systems. They can be boradly classified into..
Several studies on these different types of systems have shown that…
Though both types had relative pros and cons and could affect the frequency of biological and mechanical complications
Such as peri-implantitis, edema, and ulcer..
Lets one control the occlusion better
Peri-implant diseases like.. Peri implant mucositis, peri-impolpantitis
To overcome these problems a new retentive design was intorduced
It compensates for the shortcomings of the existing implant prosthetic systems as..
Due to abscenese of screw hole and excess cement also..
Several case studies have reported successful use of MLP[18, 19], but there were no studies reporting the objective efficacy and safety of MLP based on clinical outcomes
Thus long term clinical observation becomes very important as prosthetic changes affect implant survival
Research was carried out in Pusan National University Dental Hospital in subjects visiting between 2016-2019
The subjects included…
And the exclusion criteria was kept as..
The first table gives the information about the site of implant placement with majority being placed in the mandibular arch and posterior region respectively
The second table details the different diameters and length of implants used for treatment. Most commonly used diameter is seen to be 4 mm and most commonly used length is 10mm
Following the implant placement , the prosthetic rehab was done utilising the…The MLP has 4 Components….The cap further is divided into several components.
Body, B. Ball, C. Spring, D. Cap, E. Retention Groove of abutment
The body has several grooved hexagonal receptacles that match the hexagonal structure of the abutment cylinder to prevent the rotation of the prosthesis.
Spring envelopes the outside of the zirconia balls
2. This allows easy detachment or reattachment of prosthesis without nay loss of retention or deformation.
Before taking the impression..
Using this scan a zirconia crown was fabricated using CAD CAM. Before cementation the crown was…
Once satisfactory, crown was cemented to the cap using self adhesive resin cement
After placement, patients were divided into 3 groups for follow up
2. Discomfort like pain, foreign body sensation, neurological abnormality
The first comparison was that of marginal bone loss…For evaluating marginal bone loss radiographs were taken with the paralleling technique of iopa. Comparison was dine between the final visit with the radiograph at time of crown delivery
Figure 3: References used to measure actual marginal bone loss: (a) marginal bone level (distance from the implant platform to the top of the marginal bone) and (b) distance of the implant.
The other factors evaluated in the study were....
2. implant surface at the final recall check, and scores from 0 to 3 were checked.
3. according to the criteria of Mombelli et al. [25] at the final recall check
100 % survival rate of the 100 implants placed in 54 patients even with 2 years follow up
As no implants showed any signs of failure..
There was no significant difference among the three groups (p>0:05).
The 6-12months group showed higher probing depth than the18-24 months group (p<0:05).
mPI; score0:no detection of plaque; score 1:plaque only recognized by running a probe across the smooth marginal surface of the implant; score 2: plaque can be seen by the naked eye; score 3: abundance of soft matter.
mBI; score0: no bleeding when a periodontal probe is passed along the gingival margin adjacent to the implant; score1: isolated bleeding spots visible; score2: blood forms a confluent red line on the margin; score3: heavy or profuse bleeding.
Score 0 for both was frequently observed and there was no statistically significant difference amongst the groups.
Abutment loosening was the most commonly occurring prosthetic complication seen all the 3 groups and all found in the posterior area.
When the crown margin is located below the soft tissue margin for aesthetic reasons, in such cases the excessive cement….
The newly developed Microlocking Prosthetic system helps solve these problems.
As there is absence of access hole on the occlusal surface
Based on these results it can be concluded that..
In the present study, the marginal bone resorption of the MLP was found to be insignificant compared to the previous studies
In the study comparing a cement-retained prosthesis with a screw-retained prosthesis based on mPI and mBI..
Whereas the cement retained prosthesis periodontal indices of a cement-retained prosthesis remained to have a high value for three years of observation
suggesting that the overall periodontal indices of the MLP during the observation period are better than those of the cement-retained prosthesis presented in the previous studies.
In terms of prosthetic complications..MLP is commercially available recently and is lacking a variety of abutments with heights and diameters in comparison with other systems yet
may be caused by a small prosthetic table width in the abutment.
Therefore, in the future, the development of abutments with prosthetic table widths of various diameters, as well as the development of one-piece implants in which the fixture and abutment are integrated, may be considered.
The other complication of prosthesis fracture made of zirconia could be due to
Hence production of tha butment in variety of sizes to fit the implant systems can be of great help
Where they compared the Micro-locking prosthesis system renamed as BSRP with the Screw-cement retined prosthetic system.
When two metal conical parts, each with walls at an angle of 5 degrees or less are fitted together there will be a wedging effect due to the friction between the 2 walls. (Morse tapered connection) Additionally, if the male part has an angle of approximately 0,25 degrees more than the female conical part, a seal will be formed at the top of the cone.
Smaller the angle higher the stability
