Download Evaluation of the implant abutment interface

Evaluation of the implant abutment interface sealing
capability of different implant –abutment connections :an in
vitro study
Running title: Implant abutment interface sealing
Key wards: implant, sealing, interface, in vitro study
Radhwan Himmadi Hasan(B.D.S, M.Sc., Ph.D.)*
Hussein Saad Saeed(B.D.S)**
*Assistant professor, Department of Prosthetic Dentistry, College of
Dentistry, University of Mosul.E-mail:[email protected], Phone
nomber:009647701632273
**General practitioner, Ministry of Health.E-mail:[email protected],
Phone nomber:009647701678258
1
Evaluation of the implant abutment interface sealing capability
of different implant –abutment connections: an in vitro study
Running title: Implant abutment interface sealing
ABSTRACT
Background and objectives: Microgap is defined as the
microscopic space that exists between the implant body and
abutment.The mechanism proposed for microgap related crestal bone loss
is the role of this space as a trap for bacteria The purpose of this study
was to detect and compare bacterial microleakage at implant abutment
connection of three types abutment connections and compare between
two
torques
values
of
abutment
connectionsMaterials
and
Methods:In this experimental study eighteen dental implants,
six
external hex titanium abutments, six internal hex titanium abutments and
six morse taper titanium abutments were used in this experiment.
Abutments were fixed to implants with a torque of 20 and 30Ncm
respectively and sterilized by autoclave and each complex put in test tube
containing nutrient broth, each tube was inoculated with staphylococcus
bacterium and incubated at 37 C for 14 days.Then assemblies removed
from the tubes, cleaned and dried and separated , a small brush used to
take specimen form inside implant chamber and cultured in petri dishes
containing nutrient agar then those incubated at 37 C for 24 h , after that
colonies appeared identified and enumerated by using optical
microscope.Statistically ,Kruskal-Whallis and Mann-Whitney test were
performed
to
determine
the
significant
2
difference
at
p
≤
‫‪0.05.Results:Kruskal-whallis test confirmed that there was no‬‬
‫‪significant difference among three abutment types, Mann-Whitney‬‬
‫‪test result showed significant difference between both torques (20 and 30‬‬
‫‪Ncm) of all abutment types.Conclusions:All abutment types showed‬‬
‫‪bacterial microleakage, also as torque value increase the microleakage‬‬
‫‪decrease for all abutment types.‬‬
‫‪Keywords:implant, sealing, interface, in vitro study, internal hex, morse‬‬
‫‪taper, external hex‬‬
‫الخالصة‬
‫أهداف البحث‪:‬تهدف الدراسة الى كشف وجود و مقارنة التسرب البكتيري الدقيق في المنطقة‬
‫البينية بين الزرعة و الدعامة لثالث انواع مختلفة من ارتباط الزرعة و الدعامة و كذلك المقارنة‬
‫بين قيمتين من الشد للدعامات ‪.‬‬
‫المواد وطرائق العمل‪:‬المواد وطرائق العمل‪:‬ثمانية عشر زرعة سنية ‪ ,‬ست دعامات عرافة‬
‫التيتانيوم الخارجية و ست دعامات عرافات التيتانيوم الداخلية و ستة دعامات التيتانيوم تفتق‬
‫مورس استخدمت في هذه التجربة و قسمت الى ستة مجموعات دراسية و كل مجموعة قسمت‬
‫الى مجموعتين فرعيتين ‪,‬مجموعة فرعية من ثالث زرعات على الشد ‪ 02‬و مجموعة اخرى‬
‫على الشد ‪.02‬‬
‫تم قياس التسرب من الخارج الى داخل الزرعة السنية و ذلك بغمر الزرعات المعقمة مسبقا داخل‬
‫انابيب اختبار معقمة و تحتوي على وسط غذائي سائل لنمو البكتريا و بعد ذلك حقن السائل ب‬
‫بكتريا‪ staphylococcus aureus‬ووضعهم في الحاضنة لمدة ‪ 41‬يوم في درجة ح اررة ‪73‬‬
‫سيليزية و من ثم اخراجها و تطهيرها من الخارج بمادة الكحول و اخذ عينات من داخل الزرعة‬
‫بعد ازالة الدعامات و زرع هذه العينات في وسط غذائي أجار و من ثم قياس التجمعات البكتيرية‬
‫بواسطة الميكروسكوب الضوئي‬
‫إحصائيا تم اجراء اختبار مان ويتني و كروسكال واليس لتحديد االختالفات المعنوية عند مستوى‬
‫احتمالية (‪),,,0‬‬
‫‪ .‬النتااا‪:‬ئ ‪:‬اظه رررت النت ررائ انر ر ال يوج ررد ف ررري معن رروي ب ررين جمير ر انر رواع االرتب رراط ب ررين الزرع ررة و‬
‫الرردعامات كمررا أظهرررت النتررائ ان دعامررة الع ارفررة الداخليررة هرري ذات التسرررب ا قررل تليهررا دعامررة‬
‫تفتررق مررورس و مررن ث ررم دعامررة الع ارفررة الخارجي ررة ا علررى تس رربا‪.‬كما أظه رررت النتررائ وجررود ف ررري‬
‫‪3‬‬
‫ يتضححم مححن الجتححائ‬: :‫ت‬:‫ االسااتنت‬.‫ لجمي ر ان رواع الرردعامات‬02 ‫ و‬02 ‫معنرروي بررين قرروتي الشررد‬
‫ و كرذلك ف‬.‫أعاله أن جمي انواع الردعامات أظهررت تسرربا بكتيريرا و لرم يكرن هنراك فرري معنروي‬
‫ أظهرررت تس رربا أكثررر مررن الرردعامات المشرردودة علررى العررزم‬02 ‫ان الرردعامات المشرردودة علررى العررزم‬
.02
INTRODUCTION
Dental implant is defined as a prosthetic device made of alloplastic
material(s) implanted into the oral tissues beneath the mucosal or/and
periosteal layer, and on/or within the bone to provide retention and
support for a fixed or removable dental prosthesis; a substance that is
placed into or/and upon the jaw bone to support a fixed or removable
dental prosthesis.(1)
Over the last 30 years, the osseointegration phenomenon has drastically
changed
dental
treatment
restorative
modalities,
making
dental
implantology one of the most successful rehabilitation techniques among
medical and dental specialties with success rates reported above 90%.(2)
Developments in dental implantology evidently changed the treatment
modalities over the last 25 years. However micro-gap formation between
the surfaces of implant fixture and abutment is still one of the major
problems at the connection area which may lead to mechanical and
biological failures such as screw loosening and periimplantitis.(3)
Microgap is defined as the microscopic space that exists between the
implant body and abutment.The main mechanism proposed for microgap
related crestal bone loss is the role of this space as a trap for bacteria and
thus , as a putative etiological factor for inflammatory reaction in the periimplant soft tissues.(4)
The amount of bacterial infiltration between the implants and abutments
depends on factors such as the fit accuracy between the pieces and the
4
tightening torque and micro-movements between the connected
components during mastication.(5,6)
Several design alterations have been made in an attempt to reduce the
implant-abutment gap, thereby decreasing both its mechanical and
biological drawbacks. However, limited success has been achieved. The
inclusion of polymeric components between connection parts was able to
reduce but not eliminate bacterial colonization.(7,8)
Bacterial culture is a well-known method historically used to characterize
the oral cavity microbiota, and considered a classical reference method in
microbiology. Traditionally, culture-dependent methodologies are used to
isolate, enumerate and detect probiotic organisms, especially from mixed
cultures.(9)
.
Materials and Methods
Bacterial penetration experiment to measure leakage from outside to
inside implant abutment connection.
Dental implants with their respetive abutments including :
a. Tixos, MC Tixos Neck Implant Internal Hex (Morse)_Leader, Italy (6
Implants 4.5 mm in diameter along with their respective abutments).
b. IMPLUS, TTS Cylindrical implant
ExternalHex_Leader, Italy (6
Implants 3.75mm in diameter along with their respective abutments).
c. IMPLUS, TTS Tapered Implant Narrow Thread Internal Hex_Leader,
Italy (6 Implants 3.75 in diameter along with their respective abutments).
Samples
Grouping:Eighteen
Implants
were
divided
into
three
experimental groups(Morse taper, external hex and internal hex) and each
group divided into two subgroups:
5
Subgroup A1 (N=3) in whichmorse taper abutments were torqued to
20Ncm, Subgroup A2 (N=3) in which morse taper abutments were
torqued to 30Ncm.
Subgroup B1(N=3) in which external hex abutments weretorqued to
20Ncm, Subgroup B2(N=3) in which external hex abutments were
torqued to30Ncm.
SubgroupC1(N=3) in which internal hex abutments were torque to
20Ncm and Subgroup C2(N=3) in which internal hex abutments were
torque to 30 Ncm.
Preparation of broth and culture media :First the nutrient broth media
was prepared by adding powder 1.3 g to 100 ml distilled water and by
shaking on electrical heater until boiling ,then poured it in sterilized test
tube and sterilized it by autoclave.
Also 28 g of nutrient agar powder suspended in 100 ml of distilled water
and brought to the boil to dissolve completely and dispensed as
required(10)
Instruments Sterilization:Each implant body and abutment and all
instrument are sterilized inside surgical bags by autolave for 15 minutes
at 121 °C (250 °F) at 100 kPa (15 psi).Each implant body and abutment
was unpacked under a ventilation hood using sterile technique. (11)
Closing torque procedure:All the implants were held in an upright
position on a sterileholder. This was attached to the table, with rubber
ends allowing a firm tapping or screwing action, causing no damage to
the implant surface. All the assemblies were manipulated under aseptic
conditions.(12)
The abutment was torqued with a screw driver conneted to adigital
torqometer held in upright position by the vertical arm of a dental
surveyor to 20 Ncm and 30 Ncm.(12) (Figure 1).
6
figure-1: Closing torque procedure
Implant placement inside broth media: Each implant complex was
placed in a sterilized test tube containing nutrient broth. The level of
broth reached implant abutment connection level but not exceed the top
opening of the abutment.(11.13) (Figure 2).
Figure-2: Implant inside broth media
Inoculation procedure:Each tube then inoculated with Staphylococcus
aureus bacterium.Staphylococcus aureus (S. aureus), a major pathogen
often found in the percutaneous implant-associated infections, and its
adherence to the implanted surfaces was visualized and quantified.(11)
(Figure 3)
7
Figure-3: Inoculation the broth with Staphylococcus aurius bacteria
All procedures were performed in a sterile environment, with sterile
gloves and a laminar flow chamber (Valiclean, Brazil), which was
covered with sterile surgical cloth (Asséptico, Brazil). All equipment was
previously steam sterilized in an autoclave (Baumer, Brazil) at 121° for
15 min.(11)
Placement of tubes inside incubator: All of the test tubes were
enumerated, placed in a test tube rack in a vertical position and incubated
at 37°C(14).each tube was labeled according to its specific subgroup .
Post incubation proedure: After 14 days Each assembly was removed
from the broth after the incubation period, carefully dried with sterile
absorbent paper to remove the excess of broth. The implant-abutment
interface was disinfected with 70% alcohol and dried with absorbent
papers.(15,16), then rinsed dried and placed in a sterilized holder and the
abutments was removed and a small sterilized brush was used to take
specimen from the internal chamber of each implant.(16)
Culture proedure :Then those specimens was cultured in petri dishes
containg nutrient agar and incubated at 37°c for 24 hours.
Also another specimen from each implant internal chamber was taken
using small brush and diluted in test tube containing normal saline 0.1 ml
8
and they were plated in duplicate onto nutrient-agar plates (pouring
diluted bacterial solution then followed by pouring nutrient broth))13)
Counting of bacterial colonies:After 24 h of incubation, the purified
colonies on petri dishes were identified by means of optic microscopy to
measure number of colonies of each petri dish.
Figure-4 : Bacterial colonies
Statistical Analysis:Statistical analyses were performed by SPSS at 95%
level of significance ( The level of statistical significance was set at
alpha=0.05.) with following tests:
1. Mann-Whitney test
2. Kruskal-Wallis test
The data obtained throughout the course of study were analyzed
using Excel; Microsoft office 2010, Windows 7 Ultimate. Descriptive
statistics including mean, standard deviation, minimum and maximum
were calculated for each group.
RESULTS
The following results were obtained from observation of the colonies
under a polarized light microscope using 10Xmagnification power.
The descriptive statistics of groups(morse taper, external hex and internal
hex abutments) including mean, standard deviation were calculated
(Table 1), then a comparison among samples mean of all abutment groups
9
using Kruskal-Wallis test(Table2). According to this test, it was clear that
there was no significant difference among them.(p >0.05)
Table (1): Descriptive statistics of treatment groups and control group
Type
Sample no.
Mean (no. of
SD±
colonies)
Morse
6
113.1667
123.33275
External
6
134.5000
112.57309
Internal
6
46.6667
39.94830
Table (2): Independent Samples T-test
Type
Sample
Mean (no. of
No.
colonies)
Morse taper
6
113.1667
External hex
6
134.5000
Internal hex
6`
46.6667
Kruskal-Wallis
ChiSquare
P*
1.671
0.434
Internal hex abutments showed less mean of bacterial colonies (leakage)
followed by morse taper and finally with external hex abutments as
shown in figure (4)
10
140
120
100
Morse taper
80
External hex
60
Internal hex
40
20
0
bacterial experiment
Figure-4: Bacterial colonies mean of all abutment types
In order to explain the effect of the study parameter (torque values) on the
mean bacterial microleakage of all abutment types, Mann-Whitney test
was used for comparison between them.Table (3) illustrate the effect of
torque value on mean bacterial colonies (leakage) by making comparison
between sample mean for both torques (20 and 30 Ncm) of morse taper,
external hex and internal hex abutments respectively and appear there is
significant difference between them.(p ≤ 0.05)
Table (3): Mann-Whitney test between both torques of all abutment types
20 Ncm
30Ncm
Mean
Mean
207.0000
19.3333
External
hex
226.6667
42.3333
Internal
hex
82.3333
12.42310
Mann-Whitney test
Type
Morse
taper
T-value
-1.964-
P*
0.050*
-1.932-
0.047*
-1.913-
0.043*
.
DISCUSSIONS
Malodor and clinical signs of bleeding after removing the cover screws
or abutments may be caused by infiltration of anaerobic bacteria through
11
the implant -abutment interface. This phenomenon of infiltration can be
assessed in two ways: Verifying the passage of bacteria to the inner part
of a dental implant)(17,18), or in an inverted direction.(19,20)
The degree of penetration in a specific implant system presumably is a
multifactorial condition dependent on the precision of fit between the
implant and the abutment, the degree of micromovement between the
components, and the torque forces used to connect them(19)
The present study evaluated that there is no significant difference of
bacterialmicroleakage among the three abutment types( Morse taper,
external hex and internal hex). And all of them show bacterial infltration
along implant abutment interface and this infiltration happened due to
presence of microgaps between implant body and all abutment types.
This result agrees with Jansen et al., 1997 who determined that 13
different
types
of
prosthetic
connections
presented
bacterial
infiltration(15).This study alsoagrees withFariaet al., 2011 who showed in
his study that there is no significant difference among the same three
abutment types(11)
Also this agrees with Steinebrunneret al., 2005who tested five
different implant systems with 8 standard implant-abutment combinations
for single molar crowns but his study differ in that he exposed the
implants to a load of 1,200,000 cycles of 120 N with chewing simulator
and this load surely increased the gaps for all implant abutment
connections.(19)
Also this study disagrees with Nascimentoet al., 2012 who showed that
there is significant difference among three types of abutments( Morse
taper, External hex and Internal hex connections) in case of unloaded
condition like our study.
12
But the mean of bacterial colonies was the hieghst for external hex
abutments followed by morse taper abutment and finally the lowest mean
for internal hex abutments and that refers that the microgap in external
hex implant abutment connection is the largest followed by morse taper
and internal hex which has the smallest gap. And this also agrees with
Fariaet al., 2011.(11)
Also agrees with Jaworski et al., 2012who showed that morse taper
and external hex systems exhibited bacterial contamination, the Morse
taper implants of the system used in his study provided a better bacterial
seal than external-hexagon implants of the same system(21), This is due to
difference in microgaps between the two types.
The result of Mann-Whitney test between both torques (20 and 30 Ncm)
of all abutment types show that there is significant difference between
both torques.In contrast to the current result Smith and Turkilmaz, 2014
showed that bacterial leakage was found in all specimens, regardless of
screw torque value with titanium abutments, changing the screw torque
value from 20 to 35 Ncm did not significantly affect the amount of
bacterial leakage(22).By the same time it agrees with the same study
but with zirconia abutments, changing the screw torque value from 20 to
35 Ncm was statistically significant.
Also our study showed that as torque increased from 20 to 30 Ncm the
leakage decreased.and this agrees with Silva-Neto et al., 2012(23)
The result we obtained indicate that tightening the abutments
screwfrom 20 to 30 Ncm decreases the size of the microgap, which
suggests amore intimate fit betweenthe implant and the abutment.
CONCLUSIONS
Within limitation of this in vitro study, the conclusions are as follows:
13
The seal between the implant body and theabutment could not be
maintained in
all abutments type which showed bacterial
microleakage and this leakage was not significant between them,
internal hex showed least microleakage followed by morse taper and
finally with external hex showed highest microleakage.Alsot there
was significant difference between both torques (20 and 30 Ncm) in
all abutment types and bacterial microleakage decreased as torque
increased.
REFRENCES
1. Glossary of Prosthodontic Terms(2005).:j prosthet Dent t
2. Chuang SK, CaiT(2006). Predicting clustered dental implant survival
using frailty methods. J Dent Res; 85:1147.
3. Sahin C and Ayyilidz S (2014).Correlation between microleakage and
screw loosening at implant-abutment connection. J AdvProsthodont;
6(1): 35–38.
4. Byrne D, Houston F, Cleary R and Claffey N (1998). The fit of cast
and premachinedimplant abutments. Journal of Prosthetic Dentistry;
80(2) : 184-192
5. Scarano A, Assenza B, Piattelli M, Iezzi G, Leghissa GC, Quaranta
A, Tortora P and Piattelli A (2005). A 16-year study of the microgap
between 272 human titaniumimplants and their abutments.Journal of
Oral Implantology; 31(6) : 269-275
6. Abdelhamed
M,
Carlton
M,
Holloway
J,
McGlumphy
E,
Leblebicioglu B (2011). A Comparison of Zirconia and Titanium
Abutments for Microleakage
7. Lie Aand Jemt T(1994). Photogrammetric measurements of implant
positions. Description of a technique to determine the fit between
implants and superstructures. Clin Oral Implants Res ;5:30.
14
8. Rimondini
L, Marin
C, Brunella
F, Fini
M (2001).
Internal
contamination of a 2-component implant system after occlusal loading
and provisionally luted reconstruction with or without a washer
device. J Periodontol;72:1652.
9. Charteris WP, Kelly PM, Morelli L and Collins JK (1997). Selective
detection,enumeration and identification of potentially probiotic
Lactobacillus
andBifidobacteriumspecies
in
mixed
bacterial
populations. International Journal of Food Microbiology; 35(1) : 1–
27
10.Marshall (ed.). (1993) Standard methods for the examination of dairy
products, 16th ed. American Public Health Association, Washington,
D.C.
11.Faria R, May LG, de Vasconcellos DK, MazieroVolpato CÂ,
BottinoMA(2011). Evaluation of the bacterial leakage along the
implant-abutment interface. J Dent Implant ; 1:51-7
12.Aloise, JP, Curcio R, Laporta MZ, Rossi L, da Silva AM, and
Rapoport A. (2010).Microbial leakage through the implant-abutment
interface of Morse taper implants in vitro.Clinical Oral Implants
Research, 21 (3): 328-35
13.Filho AP, Fernandes FS,Straioto FG, Silva WJ, Cury AA
(2010).Preload loss and bacterial penetration on different implantabutment connection systems. Braz. Dent. J.; 21 (2):67-70.
14.Smith
DE,
ZarbGA
(1989).
Criteria
for
success
of
osseointegratedendosseus implants. JProsth Dent; 62 (5): 567-572.
15.Jansen VK, Conrads G and Richter EJ (1997). Microbial leakage and
marginal fit of the implant–abutment interface. The International
Journal of Oral & Maxillofacial Implants 12: 527–540.
15
16.Dibart S, Warbington M, Su MF, SkobeZ(2005) . In vitro evaluation
of the implant-abutment bacterial seal: the locking taper system. Int J
Oral Maxillofac Implants. ; 20: 732.
17.Besimo CE, Guindy JS, Lewetag D, Meyer J.( 1999) Prevention of
bacterial leakage into and from prefabricated screw-retained crowns
on implants in vitro. Int J Oral Maxillofac Implants;14:654-60.
18.Piattelli A, Scarano A, Paolantonio M, Assenza B, Leghissa GC,
Bonaventura G, (2001). Fluids and microbial penetration in the
internal part of cement-retained versus screw-retained implant abutment connections. J Periodontol;72:1146-50.
19.Steinebrunner L, Wolfart S, Bossmann K and Kern M (2005).In vitro
evaluation of bacterial leakage along the implant-abutment interface
of different implant systems.International Journal of Oral and
Maxillofacial Implants; 20(6): 875-81
20.doNascimento C, Barbosa RE, Issa JP, Watanabe E, Ito IY,
Albuquerque RF Jr ( 2008). Bacterial leakage along the implantabutment interface of premachined or cast components. Int J Oral
MaxillofacSurg; 37: 177-80.
21.Jaworski ME, Melo AC, Picheth CM (2012). Analysis of bacterial seal
at the implant-abutment interface at the external -hexagon and morse
taper-connection implants: an in vitro study usin new methodology.Int
J Oral Maxillofac Implants; 27(5) :1091-5.
16
22.Smith NA, Turkilmaz I (2014).Evaluation of the sealing capability of
implants
to
titanium
and
zirconia
abutments
against Porphyromonasgingivalis,
Prevotellaintermedia, and Fusobacteriumnucleatum under
different
screw torque values.J Pro D;112(3):561-567
23.Silva-Nito JP, Prudente MS, Carneiro TdeA, Nobilo MA, Penatti MP,
Nenes FD (2012). Micro-leakage at the implant-abutment interface
with different tightening torques in vitro.J Appl Oral Sci;20(5):581587
17
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