- Email: [email protected]
Relationship between the stiffness of the dental implant-bone system and the duration of the implant-tapping rod contact
Relationship between the stiffness of the dental implant-bone system and the duration of the implant-tapping rod contact T.M. Kaneko Research
Laboratory,
Nikon
Corporation,
Japan Received
August
1993, accepted
September
Nishi-ohi
l-6-3,
Shinagawa-ku,
Tokyo
140,
1993
ABSTRACT The physical basis of the Periotest percussion diagnosis is theoretically studied by modelling the dental implant-bone system as a simple lumped parameter system. An expression of the effective st@ness keff is derived as a function of the contact time T. The validity of k*. obtained is verrificd by a comparison with experimental values estimated from other methods. Relationships between ke. and the pure stiffness for the Kelvin- Voigt and Maxwell models are also derived. It is suggested that an increase of viscosity as well as stsffmss will &crease r. Keywords:
Dental
Med. Eng. Phys.,
implant,
stiffness,
contact
1994, Vol. 16, 310-315,
time, interface
July
INTRODUCTION Numerous attempts have been made to assess the mechanical state of the dental implant-bone interface in nondestructive ways l-4’ . Recently the possibility of auantitative assessment has been increased bv the advent ofthe Periotest instrument Siemens, Bensheim, 4,9,11,12,16-21,23,25-27,31,334 5,37-41 Germany) The Periotest method is based on measuring the time r during which a tapping rod kept horizontal is in contact with a tested implant. It has been shown empirically that this method can detect a subtle difference in the so-called clinical mobility of tooth42*. However, nothing seems to be known, either experimentally or theoretically, about quantitative relationships between r and physical quantities proper to the implant (or tooth)-bone system. In this article the Periotest diagnosis is analysed by modelling the implant-bone system (Figure la) as a simple lumped parameter system with the effect stiffness k,E (Figure 16). First, a theoretical expression of k,s is derived as a function of r. Then, k,s values are estimated for dental implants using recent biocompatible materials and healthy human incisors on the basis of the published clinical Periotest data. Finally, the effect of viscous damping on r is discussed. 1
MECHANISM
I
OF THE PERIOTEST
0 1994 Butterworth-Heinemann
for BES
r= O.O20(PTV+
21.3)
(20.26s)
[ms] for PTVsl3
(14 Tapping
Implant
rod
+x’m+--I
M
h
h’
Interface I
a
Bone
axis
Rotation
a
DIAGNOSIS
According to the researchers who participated in the development of the Periotest method, the contact time r is measured as follows43,45. First, a metal
1350-4533/94/04310-06
rod hits the surface of the specimen at a constant speed (1 O-30 cm s-l). Then, r is measured by using a small accelerometer. Mobility is expressed by an integer (-8 to + 50) called the Periotest value (PTV), to which r is related by the formulae43:
M
f”
b
0
Figure 1 Schematic diagram of a, the Periotest diagnosis and b, its lumped parameter model. Mass of the tapping rod (M), effective mass of the implant (m), equivalent stiffness of the implant-bone interface (k), effective stiffness at the tapping point (k,,), distances (h, h’), displacements of the implant (x, x’), tapping velocity (v)
St@uss
r=0.0006(PTV+4.17)*+0.50958
[ms] for PTV
Most of the clinical data hitherto published show that PTV for dental implants is slower than 13 (Table I).
DYNAMICS OF THE PERIOTEST DIAGNOSIS We express the Periotest diagnosis by a lumped parameter model as shown in Figure lb, based on
four assumptions. The first assumption is that keg, which is the effective stiffness at the tapping point, is constant, because the displacement of the implant due to percussion is considered small. Second, k,n involves the effect of viscous damping, because r is the only quantity measured. The effect of viscous damping on r is discussed in a later section. Third, both tapping rod and implant are rigid particles. We
table 1
should therefore note that in general 7 and k,r will depend on the tapping point and direction in Figure la. The effects of the tapping point on 7 and k,K are discussed briefly later. The last assumption is that the mass m takes different values, depending on whether the implant-bone interface is hard or soft. For the former case m is taken to be the sum of the mass of the implant and the effective mass of the investing cortical bone. For the latter case m is taken to e the mass of the implant alone. The impact force F acting on the implant is given by: for0StSr
F=k,rx=-(M+m)d’x/dt* From the momentum
conservation
Mu= (M+m)dx/dt
att=O
(2)
law we have (3)
Here x is the displacement of the implant taken positive in the v direction and t is the time after
Data on Periotest value PTV
Researchers
(year)
Schulte (1986)*
Kohno
estimated from Periotest: T.M. Kancko
et al. (1987)*
Takahashi
er al. (1989)‘a
Implant or healthy natural tooth
Interface or its analogue
Bone or its analogue
PTV
Incisor 1 Molar Ti (ITI) HA*-coated Ti AlrOs (Tubingen)
(Soft tissue) (Soft tissue) (Hard tissue) (Hard tissue) (Hard tissue)
In human upper and lower jawbones In human mandible Ys’ in human mandible Ys in human mandible Ys in human mandible
+13 -3 +9 -6 -6
Incisor Incisor Incisor Incisor Canine Canine Canine Canine Molar Molar Molar Molar
1 1 1 1 3 3 3 3 7 7 7 7
(Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft
In In In In In In In In In In In In
+6.0 zk 3.6 +8.4 f 3.6 +4.6 f 2.3 +5.7 zb 2.8 -0.4+ 2.6 +1.3+2.7 -0.6+ 1.9 +0.2 + 1.9 +7.0+ 3.7 +9.7 f 3.5 +5.9 + 4.5 +8.5 + 4.1
AlrOs AlzOs
(Biocerams) (Bioceram)
Saratini cl al. ( 1989) ”
AlaOs (Bioceram) AlzOs (Bioceram)
Kaneko
Ti (ITI) Ti (ITI)
(1989)r”
Hongo et al. (1989)”
Bioactive glassceramic
Iijima and Taketa
Ti (ITI-F) Ti (ITI-F)
(1990)‘s
tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue)
Tight fitting Hard adhesives
Plaster-bonding ?
Ti (ITI) Toi (ITI)
Tcerlinck
Ti (Brinemark)
et al. (1991)3’
Sakonaka et al. (1991)33
Ichiwaka
cl al. (1992) Ti
Ti (IMZ5) Ti (IMZ) HA + AlrOs-coated HA + Al,Os-coated ?
(Hard tissue) (Hard tissue)
maxilla maxilla mandible mandible maxilla (0) maxilla (d) mandible (9) mandible (d) maxilla (0) maxilla (cf) mandible (9) mandible
-3.0 -4.0
5 MS in human maxilla 9 + 12 MS in human maxilla
+5 +lO+
In porous plastic In porous plastic
+I1 and +15 -3.8 to -1.1
3.5 +
7.4 -+ 8 Ws4 in monkey mandible
In plaster OD+ + 8 Ws 4
3-4 MS in human mandible
to -0.2 to - 1.4 +8
-2.5+ -6+ +6 --* +9.5 (Lost) -5 +l
t6 MS in human maxilla 26 MS in human mandible
to +27+0 -+-3to-2 -2.1 -2.6
12 MS in human maxilla 12 MS in human mandible
+0.6 -3.8
26 MS in human mandible
-4
Plaster-bonding ?
In plaster z.3 MS in human mandible In plaster 3 Ms in human mandible
-2.2 +1.7 to +3.6 -5.0 -0.6 to +3.4
HA-coated
530 +
-3.5*
Plaster-bonding Ti Ti
(d) (0) (d) (9) (8)
+8 +12 -5 -4
= ‘10 MS* in human maxilla 23 MS in human mandible
2.8+
Ti (ITI-F) Ti (ITI-F) Buser cl al. ( 1990)‘”
human human human human human human human human human human human human
to to to to
Ti
8360 Ds in human mandible
to +8
to +2
-4.1
Notes: ‘Y, year. ‘Hydroxyapatite. 3Kyocera Inc., Japan. ‘M, month; W, week; D, day. ‘Friedrichsfeld Ltd., Germany.
Med. Eng. Phys. 1994, Vol.
16, July
311
Stt@iiss estimated from Periotest: T.M. Kancko
impact starts. Taking into account that x= 0 at t = 0 and that -dxldt has a maximum at t = r, we have keff = 7r2 (M+ m) r-*
a r-*
*O r
(4a)
= F$(M+m)(Mv)-*
(4b)
x=xesin27rft
forO?Ztsr
(5)
F=Fosin2rft
for0stsr
(6)
E
Here a’
x0(=x,,,)
f=
=
0.5~’
F,, (= F,,,)
d
[M/(M+
m)]
VT
(<2 kHzfromequation = rMv
a7
(7)
[la])
(8)
~-l
(9)
Equations (4a) and (7) are the relations between k,R and r and between x,, and r. Inequality (8) explains the reason why a low-pass filter of 2 kHz is used in the Periotest instrument43. From Equations (la) and (4a) we get: Akc,r/ketr+ -2APTV/(PTV+21.3) forPTV5 If we let APTV=fl f 0.020 ms from equation [la]), ma1 APTV measured, then IAketr/keR]e2(PTV+21.3)-1
13
13
(11)
This equation determines the resolution capacity of IQ estimated from the Periotest diagnosis, which is 15-6% for PTV of -8 to +13. On the basis of the data from the literature43’44, we assume: M = 8.4 [g] and v = 20 [cm s-‘1
(12)
Then, (PTV+21.3)-’
[lO”Nm-‘1 (13a)
= 0.00354 (8.4 + m) Fmax2
[ lo5 N m-t]
10.7(8.4+m)-‘(PTV+21.3)
<44
(13b) [,um] (14)
F max =264(PTV+21.3)-‘27.7
[N]
(15)
for PTV s 13. Here m is expressed in grams. Values of k,E calculated from Equation (13a) are plotted against PTV in Figure 2, together with the experimental values shown in Table 2. We see a reasonable agreement between theory and experiment. It should be noted, however, that k,r will depend on the tapping point, as follows. Assume that the elasticity of the implant-bone system is due to the spring which has a stiffness k at point h’, as shown in Figure la. Then, the displacment x’ and the force F’ at this point are written as x’ = xh’/(h + h’) Further, since balanced,
312
0 _
a
-5
and
Relationship value \(PTV).
torque
Med. Eng. Phys.
around
(16) the rotation
+ 10
between the effective stiffness (ken) and the Solid lines were calculated from equation
F’h’ = F(h+
axis
is
(17)
h’)
From Equations
(2)) (13a), ( 16) and ( 17) we have
keff= k[h’l(h+h’)]* PTV=
(18)
5?rk-0.5(8.4+m)0.5(1
+/z/h’) -21.3
(19)
Equation (18) indicates that keE decreases with increasing h. Equation 19 explains the experimental fact that, as h increases, PTV tends to increase1’,37. If no rotation axis exists, then k,fi-= k. Therefore, in such a case PTV would be independent of the tapping point. OF VISCOUS
DAMPING
In this section we examine the effect of viscous damping on the contact time r. First we express the Periotest diagnosis by the Kelvin-Voigt model shown in Figure 3a. The viscosity qu is assumed to be small on the basis of the clinical results obtained for healthy and unhealthy teeth’7pM148 and for Al203 (Bioceram) implants”. The impact force F acting on the implant is given by F= k,x+
q,,dxldt=
-(M+m)
From the momentum dxldt = [M/(M+
d*xldt*
conservation
m)] v
(20)
law we have:
at t = 0
(21)
Taking into account that x= 0 at t = 0 and that dxldt has a maximum at t = 7, we have, after a lengthy calculation, kcff+kk,[l
- (l/?r) h,0.5+ (l/8) A,-
(~/ST) A,1.5]-2
+ m)/k,]0-5 (1 - 7r-l h,0.5)
(22) (23)
where A, = vu2/[k. (M = m)]
1994, Vol. 16, July
+5
Periotest (Isa) by assuming the value of the effective mass (m) for the implant or tooth. Experimental values (OL7, ?? 44,46, 03’, present work) were taken from Tables 1 and 2
r i r[(M
F’ = kx’
0 PTV
Figure 2
EFFECT
ke8= 25 m2 (8.4 + m)
x,,,=
5
(10)
AT= (therefore, which is the minifor PTVS
Y
(24)
Stiffness estimated from Periotest: T.M. Kaneko T&le 2
Experimental
values of stiffness
Researchers (year)
Mishmima Nagata
( 1973)4”
(1976)+’
Implant, its analogue or healthy tooth
Interface or its analogue
Bone or its analogue
Stiffness (lOsNm-‘)
Incisor Incisor
1 1
(Soft tissue) (Soft tissue)
In human (d) In human (9)
2.75-4.02’ 2.45-3.701
Incisor Incisor
1 1
(Soft tissue) (Soft tissue)
In human maxilla In human mandible
1.724-3.1392 1.297-2.162’
maxilla maxilla
Scholz et al. (1980)’
Incisor A1203 (Tiibingen)
(Soft tissue) (Hard tissue)
In human maxilla 3 Ms4 in human jawbone
3.03 4.0 and 6.03
Oka et al. ( 1988)48
Incisor 1 Incisor 1
(Soft tissue) (Soft tissue)
In human maxilla In human mandible
2.98’ 1 .6Z5 2.0’ (PTV = +5) 2.1#3.0’ (Frv =+10#+8)
Al2O3 (Bioceram)
?
5 Ms in human maxilla
A1203 (Bioceram)
?
9 # 12 MS in human maxilla
Teerlinck et al. ( 1991)3’
?
?
Metal
11 and 4.@ (PTV = -4 and +2)
Present work
Aluminium
Adhesive tape
Metal (force transducer)
137 (PTV = -7
Saratani
et al. (1989) ”
alloy
to -6)
No&s: ‘Values of the pure stiffness estimated from the mechanical impedance method ‘Values of the pure stiffness estimated from the resonance method sEstimated from the rapid recovery displacement data ‘M, month 5Value of the pure stiffness estimated from another impact method ~‘Estimated using equation (13b) from observed values of the impact force (m = 1 .Og for s and 0.2 g for ’ being assumed)
Equation (22) is the relation between the effective stiffness k,,r shown in Figure lb and the pure stiffness k, in the Kelvin-Voigt model. Equation (23) shows that the contact time will be reduced by an increase of v,, as well as that of k,. Next we express the Periotest diagnosis by the Maxwell model shown in Figure 36, where the viscosity TM is assumed to be large. In this case, the impact force F acting on the implant is given by: F= k&x-xl) = qMdx,/dt= -(M=
m) d*xldt*
(25)
Taking into account that x = x1 = 0 at t = 0 and that -dxldt has a maximum at t = r, we have, after a lengthy calculation,
i’ m
%l 5l
a a, Kelvin-Voigt
X
\1
b
and b, Maxwell models of the Periotest diagnosis. Mass of the tapping rod (M), effective mass of the implant (m), tapping velocity (u), stiffnesses (k., knr), viscosities (q., I)M), displacement of the implant (x), displacement of the dashpot qM (XI)
T= T[(ikf=
m)/k,+#.5 (1 - 0.25 AM-1)4’5
(26) (27)
where AM =
‘7M*&w(M+
m)l
(28)
Equation (26) is the relation between k,K and the pure stiffness kM in the Maxwell model. Equation (27) shows that the contact time will be reduced by an increase of Ed as well as that of kM. It should be noted that the clinical result of Saratani et al.” for an AlpOs(Bioceram) implant indicated that all values of k, (= kM), vu and qM increased with decreasing PTV. Further, the clinical results of Mishima& and Oka et aLM showed that both values of k, and 7, are distinctively larger for healthy teeth than for unhealthy teeth.
The Periotest diagnosis has been analysed theoretictally by modelling the implant-bone system as a lumped parameter system, shown in Figure lb. Expressions of the effective stiffness k,E have been derived as functions of the contact time 7 and the Periotest value PTV (Equations [4a] and [13a]. The validity of keK obtained has been verified by a comparison with experimental values.. Relations between k,r and the pure stiffnesses k, and k,cl in the Kelvin-Voigt and Maxwell models have also been derived. It has been suggested that an increase of viscosity as well as stiffness will decrease 7 and therefore PTV.
xl
A& Figure 3
1
keff= kM(l = 0.25A,-‘)
REFERENCES 1. Picton DCA, Johns RB, Wills DJ, Davies WIR. relationship between the mechanisms of tooth implant support. Oral Sci Rev 1974; 3: 3-22. W, Lukas D, Schulte W. 2. Scholz F, Holzwarth
Med. Eng, Phys. 1994, Vol. 16,Joly
The and Die
313
Stiffss
3.
4.
5.
6.
7
8.
9.
10.
11.
12.
estimatedfrom Periotest: TM, Kaneko
Dampfungseigenschaften des Parodontiums im Vergleich sum Tiibinger Sofortimplantat. Dtsch Zuhnci’r& Z 1980; 35: 709-12. Scholz F. Bewegungsverhalten bei Stossanregung des Tiibinger Implantates im Vergleich zum natiirlichen Zahn. Dtsch Zahniirztl Z 1981; 36: 565-70. Schulte W. Messung des Sampfungsverhaltens enossaler Implantate mit dem Periotestverfahren. Dtsch Z Zahniirztl Implantol 1986; 2: 1 l-12. Ney Th. Die vertikale Beweglichkeit des Tiibinger Implantates im Vergleich zum natiirlichen Zahn. Dtsch Z ZahnGztl Implant01 1986; 2: 17-20. Kaneko T, Nagai Y, Ogino M, Futami T, Ichimura T. Acoustoelectric technique for assessing the mechanical J Biomed state of the dental implant-bone interface. Mater Res 1986; 20: 169-76. Kudo K, Fujioka Y, Miyasawa M, Ishibashi K, Shioyama T, Ishikawa F, Kamegai T, Nakano H, Seino Y. Clinical application of dental root implant coated with bioglass, Part 1: Result of implantation. Jpn J Oral Maxillofac Surg 1986; 32: 2083-g. Sugihara K, Yamashita S. Clinical application of dental root implant coated with bioglass, Part 1: Procedure of implantation. J Jpn Stomatol Sot 1987; 36: 96-105. Ogiso M, Kaneda H, Shiota M, Mitsuwa T, Wakuda H, Aikawa S, Uoshima K, Masuda T, Kaneda R, Tomizuka K, Tabata T, Sugimoto H. Apatite implant, 2-piece implant system. J Dent Med 1987; 25: 617-33. Kaneko T. Assessment of the interfacial rigidity of bone implants from vibrational signals. J Mater Sci 1987; 22: 3495-502 Takigawa H, Yamauchi M, Nigauri A, Satoh F, Shimizu M, Kawano J. Evaluation of Periotest for prosthetic clinical application. J Jpn Prosthodont Sot 1988; 32: 189-98. Ogiso M, Kaneda H, Shiota M, Mitsuwa T, Wakuda H, Aikawa S, Uoshima K, Masuda T, Kaneda R, Tomizuka K, Ishihara S, Tabata T, Sugimoto H, Kanbayashi H, Matsumoto S, Uehara K, Hidaka T. Apatite P-piece implant, Part 3: Clinical trial. J Jpn Prosthodont Sot 1988;
CaO-PPOS-MgO-SiOs-CaF system glass ceramic tooth implants in monkeys. J Jpn Ass Periodont 1989; 31: 111929. 22. Kamegai T, Nakano H, Seino Y, Ishikawa F. The utilization of acoustoelectric diagnosis in fitting condition at the implantation of bioactive glass coated dental root implant and their clinical estimation. J Jpn Sot Biomater 1990; 8: 2-10.
23. Yamane
S, Shimogoryo R, Tsuda T. Mobility of bon&t and osseointegrated implant before the set of the superstructure. J Jpn Sot Oral Implant01 1990; 3: 19-24. 24. Kudo K, Miyasawa M, Fujioka Y, Kamegai T, Nakano H, Seino Y, Ishikawa F, Shioyama T, Ishibashi K. Clinical application of dental implant with root of coated bioglass: short-term results. Oral Surg Oral Med Oral Path01 1990; 70: 18-23. 25 Iijima T, Takeda T. An observation of chronological change of mobility of IT1 implants with Periotest. J Jpn Sot Oral Implant01 1990; 3: 191-9. 26. Buser D, Weber HP, Lang NP. Tissue integration of nonsubmerged implants: l-year results of a prospective study with 100 IT1 hollow-cylinder and hollow-screw Clin Oral Imp1 Res 1990; 1: 33-40. implants. 27. Olive J, Aparicio C. The Periotest method as a measure Int J Oral of osseointegrated oral implant stability. Maxillofac Implants 1990; 5: 390-400.
28. Kaneko
29.
30.
31.
32: 523-33. S, Nakagawa S, Shimogoryo R, Tsuda T. 13. Yamane Percussion sound of IT1 implant. J Jpn Sot Oral Implant01 1988; 1: 240-4. 14 Kamegai T, Ishikawa F, Nakano H, Seino Y, Fujioka Y, Kudo K, Miyasawa M, Ishibashi K, Shioyama T. Clinical and short term results of dental root applications implantation using materials coated with bioactive glass. In: Kawahara M, ed. Oral Implantology and Biomaterials Amsterdam: Elsevier, 1989, 121-6. of dental root 15. Fujino M, Ogino M. Clinical application implant using bioactive glass. In: Kawahara M, ed. Oral Implantolosy and Biomaterials Amsterdam: Elsevier, 1989, 145-g. T, Sugaya K, Nojima M, Koshihara Y, Haga 16. Takahashi M, Nakagawa K, Hinoide M, Asai Y. Clinical study of Bioceram porous implant. In: Kawahara M, ed. Oral Implantologv and Biomaterials Amsterdam: Elsevier, 1989, 163-8. 17. Saratani K, Yoshida S, Oka H, Kawazoe T. The clinical measurement of the biomechanical mobility of dental implants. In: Kawahara H, ed. Oral Implantology and Biomaterials Amsterdam: Elsevier, 1989, 305-10. S, Shimogoryo R, Tsuda T. Mobility of the 18. Yamane bridge with implant abutments. J Jpn Sot Oral Implant01 1989; 2: 34-8. B, Schulte W. A comparative study of results 19. D’Hoedt with various endosseous implant systems. Int J Oral Maxillofac Implants 1989; 4: 95-105. between acoustic and mechani20. Kaneko T. Comparison cal tapping methods for assessing the interfacial states of bone implants. J Mater Sci 1989; 24: 2820-4. Y, Asano M, Kawanami M, 21. Hongo 0, Mukainakano Kato H. Clinical and histopathological observation of
314
Med. Eng. Phys. 1994, Vol. 16, July
32.
33.
34.
N, Kasahara Y, Kadota H, Fujino M, Senuma S, Sato K. Experimental study on measuring equipment for micro-mobility of dental root implants (Nikon NSP1000). J Jpn Sot Biomater 1990; 8: 287-93. Kaneko T. Assessment of the dental implant-bone J Mater Sci Lett interface from a pulsed microvibration. 1991; 10: 185-7. Matsuda T, Fukuhara H, Fujisaki M, Sugihara K, Onizuka T, Yokota M. Clinical evaluation of a measuring equipment for micro-mobility of dental implant. J Jpn Sot Biomater 1991; 9: 3-l 1. Teerlinck J, Quirynen M, Darius P, Van Steenberghe D. Periotest: an objective clinical diagnosis of bone apposition toward implants. Int J Oral Maxillofac Implants 1991; 6: 55-61. Kaneko T. Pulsed oscillation technique for assessing the mechanical state of the dental implant-bone interface. Biomaterials 1991; 12: 555-60. Sakonaka T, Takeshita F, Akedo H, Morimoto K, Suetsugu T. Mobile examination of Sumicikon and IMZ implant using Periotest. J Jpn Prosthodont Sot 1991; 35: 632-5. Murakami H, Matsuda T, Kishi T, Nashimoto M, Kato T, Tsunosue U. A case report about mobility of implants by PERIOTEST, Part 2: Sumicikon’s PER10 TEST values, distinctions of sex and age. J Jpn Sot Oral Implantol 1991; 4: 221-30.
35. Ichikawa
36. 37.
38.
39.
40.
T, Miyamoto M, Horisaka Y, Okamoto Y, Horiuchi M, Matsumoto N, Yoshida H. Mobility of twopiece apatite implants measured with Periotest and its clinical evaluation. J Jpn Sot Oral Implant01 1992; 5: 51-6. Brunski JB. Biomechanical factors affecting the bonedental implant interface. Clin Mater 1992; 10: 153-201. Yamane S, Shimogoryo R, Tsuda T, Tanaka K. Mobility of Bonelit screw implant. J Jpn Sot Oral Implant01 1992; 5: 223-7. Murakami H, Matsuki K, Nishijima Y, Nakanishi M, Kumonda T, Miyamoto K, Okawa M. A case report about mobility of implants by PERIOTEST, Part 4: Bonefit’s PER10 TEST values. J Jpn Sot Oral Implant01 1992; 5: 240-g. Kishi T, Murakami H, Yamamoto T, Saitou J, Asada K, Shioya H, Nishijima Y, Takagi S. The mobility of implants with PERIOTEST, Part 3: Double head type of SUMICIKON. J Jpn Sot Oral Zmplantol 1992; 5: 250-5. Aparicio C, Branemark P-I, Keller EE, Olive J. Recon-
Stzffness estimated from Periotest: T.M. Kancko
41.
42.
43.
44.
struction of the premaxilla with autogenous iliac bone in Znt J Oral combination with osseointegrated implants. Maxillofac Implants 1993; 8: 61-7. Salonen MAM, Oikarinen K, Virtanen K, Pernu H. Failures in the osseointegration of endosseous implants. Int J Oral Maxillofac Implants 1993; 8: 92-7. K&rig M, Lukas D, Quante F, Schulte W, Topkaya A. zur quantitativen Beurteilung des Messverfahren Schweregrades von Parodontopathien (Periotest). Dtsch Zahtirztl Z 1981; 36: 451-4. D’Hoedt B, Lukas D, Miihlbradt L, Scholz F, Schulte W, Quante F, Topkaya A. Das PeriotestverfahrenEntwicklung und klinische Priifung. Dtsch Zahniirrtl 2 1985; 40: 113-25. Kohno S, Sato T, Tabata T. PERIOTEST - a new measuring instrument of the dynamic periodontal func-
tion and the guide to its application.
Quintessence 1987; 6:
187-95. 45. Schulte W, D’Hoedt B, Lukas D. Miihlbradt L, Scholz F, Bretschi J, Frey D, Gudat H, K&rig M, Marki M, Quante F, Schief A, Topkaya A. Periotest - neues messverfahren Zahniirztl Mitt 1983; 73: der Funktion des Parodontiums. 1229-40. 46. Mishima J. Clinical study of viscosity and elasticity on periodontal tissue: relationship between the conditions of periodontal disease and viscoelasticity of periodontal tissue. J Jjm Stomatol Sot 1973; 40: 367-88. 47. Nagata K. Study of the frequency response of the periodontium. J Jpn Prosthodont Sot 1976; 20: 375-92. 48. Oka H, Yamamoto T, Kawazoe T, Saratani K, Hikida Y. Impact response of periodontal tissues. Med Biol Eng Comput 1988; 26: 260-6.
Med. Eng. Phys. 1994, Vol. 16, July
315
Laboratory,
Nikon
Corporation,
Japan Received
August
1993, accepted
September
Nishi-ohi
l-6-3,
Shinagawa-ku,
Tokyo
140,
1993
ABSTRACT The physical basis of the Periotest percussion diagnosis is theoretically studied by modelling the dental implant-bone system as a simple lumped parameter system. An expression of the effective st@ness keff is derived as a function of the contact time T. The validity of k*. obtained is verrificd by a comparison with experimental values estimated from other methods. Relationships between ke. and the pure stiffness for the Kelvin- Voigt and Maxwell models are also derived. It is suggested that an increase of viscosity as well as stsffmss will &crease r. Keywords:
Dental
Med. Eng. Phys.,
implant,
stiffness,
contact
1994, Vol. 16, 310-315,
time, interface
July
INTRODUCTION Numerous attempts have been made to assess the mechanical state of the dental implant-bone interface in nondestructive ways l-4’ . Recently the possibility of auantitative assessment has been increased bv the advent ofthe Periotest instrument Siemens, Bensheim, 4,9,11,12,16-21,23,25-27,31,334 5,37-41 Germany) The Periotest method is based on measuring the time r during which a tapping rod kept horizontal is in contact with a tested implant. It has been shown empirically that this method can detect a subtle difference in the so-called clinical mobility of tooth42*. However, nothing seems to be known, either experimentally or theoretically, about quantitative relationships between r and physical quantities proper to the implant (or tooth)-bone system. In this article the Periotest diagnosis is analysed by modelling the implant-bone system (Figure la) as a simple lumped parameter system with the effect stiffness k,E (Figure 16). First, a theoretical expression of k,s is derived as a function of r. Then, k,s values are estimated for dental implants using recent biocompatible materials and healthy human incisors on the basis of the published clinical Periotest data. Finally, the effect of viscous damping on r is discussed. 1
MECHANISM
I
OF THE PERIOTEST
0 1994 Butterworth-Heinemann
for BES
r= O.O20(PTV+
21.3)
(20.26s)
[ms] for PTVsl3
(14 Tapping
Implant
rod
+x’m+--I
M
h
h’
Interface I
a
Bone
axis
Rotation
a
DIAGNOSIS
According to the researchers who participated in the development of the Periotest method, the contact time r is measured as follows43,45. First, a metal
1350-4533/94/04310-06
rod hits the surface of the specimen at a constant speed (1 O-30 cm s-l). Then, r is measured by using a small accelerometer. Mobility is expressed by an integer (-8 to + 50) called the Periotest value (PTV), to which r is related by the formulae43:
M
f”
b
0
Figure 1 Schematic diagram of a, the Periotest diagnosis and b, its lumped parameter model. Mass of the tapping rod (M), effective mass of the implant (m), equivalent stiffness of the implant-bone interface (k), effective stiffness at the tapping point (k,,), distances (h, h’), displacements of the implant (x, x’), tapping velocity (v)
St@uss
r=0.0006(PTV+4.17)*+0.50958
[ms] for PTV
Most of the clinical data hitherto published show that PTV for dental implants is slower than 13 (Table I).
DYNAMICS OF THE PERIOTEST DIAGNOSIS We express the Periotest diagnosis by a lumped parameter model as shown in Figure lb, based on
four assumptions. The first assumption is that keg, which is the effective stiffness at the tapping point, is constant, because the displacement of the implant due to percussion is considered small. Second, k,n involves the effect of viscous damping, because r is the only quantity measured. The effect of viscous damping on r is discussed in a later section. Third, both tapping rod and implant are rigid particles. We
table 1
should therefore note that in general 7 and k,r will depend on the tapping point and direction in Figure la. The effects of the tapping point on 7 and k,K are discussed briefly later. The last assumption is that the mass m takes different values, depending on whether the implant-bone interface is hard or soft. For the former case m is taken to be the sum of the mass of the implant and the effective mass of the investing cortical bone. For the latter case m is taken to e the mass of the implant alone. The impact force F acting on the implant is given by: for0StSr
F=k,rx=-(M+m)d’x/dt* From the momentum
conservation
Mu= (M+m)dx/dt
att=O
(2)
law we have (3)
Here x is the displacement of the implant taken positive in the v direction and t is the time after
Data on Periotest value PTV
Researchers
(year)
Schulte (1986)*
Kohno
estimated from Periotest: T.M. Kancko
et al. (1987)*
Takahashi
er al. (1989)‘a
Implant or healthy natural tooth
Interface or its analogue
Bone or its analogue
PTV
Incisor 1 Molar Ti (ITI) HA*-coated Ti AlrOs (Tubingen)
(Soft tissue) (Soft tissue) (Hard tissue) (Hard tissue) (Hard tissue)
In human upper and lower jawbones In human mandible Ys’ in human mandible Ys in human mandible Ys in human mandible
+13 -3 +9 -6 -6
Incisor Incisor Incisor Incisor Canine Canine Canine Canine Molar Molar Molar Molar
1 1 1 1 3 3 3 3 7 7 7 7
(Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft (Soft
In In In In In In In In In In In In
+6.0 zk 3.6 +8.4 f 3.6 +4.6 f 2.3 +5.7 zb 2.8 -0.4+ 2.6 +1.3+2.7 -0.6+ 1.9 +0.2 + 1.9 +7.0+ 3.7 +9.7 f 3.5 +5.9 + 4.5 +8.5 + 4.1
AlrOs AlzOs
(Biocerams) (Bioceram)
Saratini cl al. ( 1989) ”
AlaOs (Bioceram) AlzOs (Bioceram)
Kaneko
Ti (ITI) Ti (ITI)
(1989)r”
Hongo et al. (1989)”
Bioactive glassceramic
Iijima and Taketa
Ti (ITI-F) Ti (ITI-F)
(1990)‘s
tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue) tissue)
Tight fitting Hard adhesives
Plaster-bonding ?
Ti (ITI) Toi (ITI)
Tcerlinck
Ti (Brinemark)
et al. (1991)3’
Sakonaka et al. (1991)33
Ichiwaka
cl al. (1992) Ti
Ti (IMZ5) Ti (IMZ) HA + AlrOs-coated HA + Al,Os-coated ?
(Hard tissue) (Hard tissue)
maxilla maxilla mandible mandible maxilla (0) maxilla (d) mandible (9) mandible (d) maxilla (0) maxilla (cf) mandible (9) mandible
-3.0 -4.0
5 MS in human maxilla 9 + 12 MS in human maxilla
+5 +lO+
In porous plastic In porous plastic
+I1 and +15 -3.8 to -1.1
3.5 +
7.4 -+ 8 Ws4 in monkey mandible
In plaster OD+ + 8 Ws 4
3-4 MS in human mandible
to -0.2 to - 1.4 +8
-2.5+ -6+ +6 --* +9.5 (Lost) -5 +l
t6 MS in human maxilla 26 MS in human mandible
to +27+0 -+-3to-2 -2.1 -2.6
12 MS in human maxilla 12 MS in human mandible
+0.6 -3.8
26 MS in human mandible
-4
Plaster-bonding ?
In plaster z.3 MS in human mandible In plaster 3 Ms in human mandible
-2.2 +1.7 to +3.6 -5.0 -0.6 to +3.4
HA-coated
530 +
-3.5*
Plaster-bonding Ti Ti
(d) (0) (d) (9) (8)
+8 +12 -5 -4
= ‘10 MS* in human maxilla 23 MS in human mandible
2.8+
Ti (ITI-F) Ti (ITI-F) Buser cl al. ( 1990)‘”
human human human human human human human human human human human human
to to to to
Ti
8360 Ds in human mandible
to +8
to +2
-4.1
Notes: ‘Y, year. ‘Hydroxyapatite. 3Kyocera Inc., Japan. ‘M, month; W, week; D, day. ‘Friedrichsfeld Ltd., Germany.
Med. Eng. Phys. 1994, Vol.
16, July
311
Stt@iiss estimated from Periotest: T.M. Kancko
impact starts. Taking into account that x= 0 at t = 0 and that -dxldt has a maximum at t = r, we have keff = 7r2 (M+ m) r-*
a r-*
*O r
(4a)
= F$(M+m)(Mv)-*
(4b)
x=xesin27rft
forO?Ztsr
(5)
F=Fosin2rft
for0stsr
(6)
E
Here a’
x0(=x,,,)
f=
=
0.5~’
F,, (= F,,,)
d
[M/(M+
m)]
VT
(<2 kHzfromequation = rMv
a7
(7)
[la])
(8)
~-l
(9)
Equations (4a) and (7) are the relations between k,R and r and between x,, and r. Inequality (8) explains the reason why a low-pass filter of 2 kHz is used in the Periotest instrument43. From Equations (la) and (4a) we get: Akc,r/ketr+ -2APTV/(PTV+21.3) forPTV5 If we let APTV=fl f 0.020 ms from equation [la]), ma1 APTV measured, then IAketr/keR]e2(PTV+21.3)-1
13
13
(11)
This equation determines the resolution capacity of IQ estimated from the Periotest diagnosis, which is 15-6% for PTV of -8 to +13. On the basis of the data from the literature43’44, we assume: M = 8.4 [g] and v = 20 [cm s-‘1
(12)
Then, (PTV+21.3)-’
[lO”Nm-‘1 (13a)
= 0.00354 (8.4 + m) Fmax2
[ lo5 N m-t]
10.7(8.4+m)-‘(PTV+21.3)
<44
(13b) [,um] (14)
F max =264(PTV+21.3)-‘27.7
[N]
(15)
for PTV s 13. Here m is expressed in grams. Values of k,E calculated from Equation (13a) are plotted against PTV in Figure 2, together with the experimental values shown in Table 2. We see a reasonable agreement between theory and experiment. It should be noted, however, that k,r will depend on the tapping point, as follows. Assume that the elasticity of the implant-bone system is due to the spring which has a stiffness k at point h’, as shown in Figure la. Then, the displacment x’ and the force F’ at this point are written as x’ = xh’/(h + h’) Further, since balanced,
312
0 _
a
-5
and
Relationship value \(PTV).
torque
Med. Eng. Phys.
around
(16) the rotation
+ 10
between the effective stiffness (ken) and the Solid lines were calculated from equation
F’h’ = F(h+
axis
is
(17)
h’)
From Equations
(2)) (13a), ( 16) and ( 17) we have
keff= k[h’l(h+h’)]* PTV=
(18)
5?rk-0.5(8.4+m)0.5(1
+/z/h’) -21.3
(19)
Equation (18) indicates that keE decreases with increasing h. Equation 19 explains the experimental fact that, as h increases, PTV tends to increase1’,37. If no rotation axis exists, then k,fi-= k. Therefore, in such a case PTV would be independent of the tapping point. OF VISCOUS
DAMPING
In this section we examine the effect of viscous damping on the contact time r. First we express the Periotest diagnosis by the Kelvin-Voigt model shown in Figure 3a. The viscosity qu is assumed to be small on the basis of the clinical results obtained for healthy and unhealthy teeth’7pM148 and for Al203 (Bioceram) implants”. The impact force F acting on the implant is given by F= k,x+
q,,dxldt=
-(M+m)
From the momentum dxldt = [M/(M+
d*xldt*
conservation
m)] v
(20)
law we have:
at t = 0
(21)
Taking into account that x= 0 at t = 0 and that dxldt has a maximum at t = 7, we have, after a lengthy calculation, kcff+kk,[l
- (l/?r) h,0.5+ (l/8) A,-
(~/ST) A,1.5]-2
+ m)/k,]0-5 (1 - 7r-l h,0.5)
(22) (23)
where A, = vu2/[k. (M = m)]
1994, Vol. 16, July
+5
Periotest (Isa) by assuming the value of the effective mass (m) for the implant or tooth. Experimental values (OL7, ?? 44,46, 03’, present work) were taken from Tables 1 and 2
r i r[(M
F’ = kx’
0 PTV
Figure 2
EFFECT
ke8= 25 m2 (8.4 + m)
x,,,=
5
(10)
AT= (therefore, which is the minifor PTVS
Y
(24)
Stiffness estimated from Periotest: T.M. Kaneko T&le 2
Experimental
values of stiffness
Researchers (year)
Mishmima Nagata
( 1973)4”
(1976)+’
Implant, its analogue or healthy tooth
Interface or its analogue
Bone or its analogue
Stiffness (lOsNm-‘)
Incisor Incisor
1 1
(Soft tissue) (Soft tissue)
In human (d) In human (9)
2.75-4.02’ 2.45-3.701
Incisor Incisor
1 1
(Soft tissue) (Soft tissue)
In human maxilla In human mandible
1.724-3.1392 1.297-2.162’
maxilla maxilla
Scholz et al. (1980)’
Incisor A1203 (Tiibingen)
(Soft tissue) (Hard tissue)
In human maxilla 3 Ms4 in human jawbone
3.03 4.0 and 6.03
Oka et al. ( 1988)48
Incisor 1 Incisor 1
(Soft tissue) (Soft tissue)
In human maxilla In human mandible
2.98’ 1 .6Z5 2.0’ (PTV = +5) 2.1#3.0’ (Frv =+10#+8)
Al2O3 (Bioceram)
?
5 Ms in human maxilla
A1203 (Bioceram)
?
9 # 12 MS in human maxilla
Teerlinck et al. ( 1991)3’
?
?
Metal
11 and 4.@ (PTV = -4 and +2)
Present work
Aluminium
Adhesive tape
Metal (force transducer)
137 (PTV = -7
Saratani
et al. (1989) ”
alloy
to -6)
No&s: ‘Values of the pure stiffness estimated from the mechanical impedance method ‘Values of the pure stiffness estimated from the resonance method sEstimated from the rapid recovery displacement data ‘M, month 5Value of the pure stiffness estimated from another impact method ~‘Estimated using equation (13b) from observed values of the impact force (m = 1 .Og for s and 0.2 g for ’ being assumed)
Equation (22) is the relation between the effective stiffness k,,r shown in Figure lb and the pure stiffness k, in the Kelvin-Voigt model. Equation (23) shows that the contact time will be reduced by an increase of v,, as well as that of k,. Next we express the Periotest diagnosis by the Maxwell model shown in Figure 36, where the viscosity TM is assumed to be large. In this case, the impact force F acting on the implant is given by: F= k&x-xl) = qMdx,/dt= -(M=
m) d*xldt*
(25)
Taking into account that x = x1 = 0 at t = 0 and that -dxldt has a maximum at t = r, we have, after a lengthy calculation,
i’ m
%l 5l
a a, Kelvin-Voigt
X
\1
b
and b, Maxwell models of the Periotest diagnosis. Mass of the tapping rod (M), effective mass of the implant (m), tapping velocity (u), stiffnesses (k., knr), viscosities (q., I)M), displacement of the implant (x), displacement of the dashpot qM (XI)
T= T[(ikf=
m)/k,+#.5 (1 - 0.25 AM-1)4’5
(26) (27)
where AM =
‘7M*&w(M+
m)l
(28)
Equation (26) is the relation between k,K and the pure stiffness kM in the Maxwell model. Equation (27) shows that the contact time will be reduced by an increase of Ed as well as that of kM. It should be noted that the clinical result of Saratani et al.” for an AlpOs(Bioceram) implant indicated that all values of k, (= kM), vu and qM increased with decreasing PTV. Further, the clinical results of Mishima& and Oka et aLM showed that both values of k, and 7, are distinctively larger for healthy teeth than for unhealthy teeth.
The Periotest diagnosis has been analysed theoretictally by modelling the implant-bone system as a lumped parameter system, shown in Figure lb. Expressions of the effective stiffness k,E have been derived as functions of the contact time 7 and the Periotest value PTV (Equations [4a] and [13a]. The validity of keK obtained has been verified by a comparison with experimental values.. Relations between k,r and the pure stiffnesses k, and k,cl in the Kelvin-Voigt and Maxwell models have also been derived. It has been suggested that an increase of viscosity as well as stiffness will decrease 7 and therefore PTV.
xl
A& Figure 3
1
keff= kM(l = 0.25A,-‘)
REFERENCES 1. Picton DCA, Johns RB, Wills DJ, Davies WIR. relationship between the mechanisms of tooth implant support. Oral Sci Rev 1974; 3: 3-22. W, Lukas D, Schulte W. 2. Scholz F, Holzwarth
Med. Eng, Phys. 1994, Vol. 16,Joly
The and Die
313
Stiffss
3.
4.
5.
6.
7
8.
9.
10.
11.
12.
estimatedfrom Periotest: TM, Kaneko
Dampfungseigenschaften des Parodontiums im Vergleich sum Tiibinger Sofortimplantat. Dtsch Zuhnci’r& Z 1980; 35: 709-12. Scholz F. Bewegungsverhalten bei Stossanregung des Tiibinger Implantates im Vergleich zum natiirlichen Zahn. Dtsch Zahniirztl Z 1981; 36: 565-70. Schulte W. Messung des Sampfungsverhaltens enossaler Implantate mit dem Periotestverfahren. Dtsch Z Zahniirztl Implantol 1986; 2: 1 l-12. Ney Th. Die vertikale Beweglichkeit des Tiibinger Implantates im Vergleich zum natiirlichen Zahn. Dtsch Z ZahnGztl Implant01 1986; 2: 17-20. Kaneko T, Nagai Y, Ogino M, Futami T, Ichimura T. Acoustoelectric technique for assessing the mechanical J Biomed state of the dental implant-bone interface. Mater Res 1986; 20: 169-76. Kudo K, Fujioka Y, Miyasawa M, Ishibashi K, Shioyama T, Ishikawa F, Kamegai T, Nakano H, Seino Y. Clinical application of dental root implant coated with bioglass, Part 1: Result of implantation. Jpn J Oral Maxillofac Surg 1986; 32: 2083-g. Sugihara K, Yamashita S. Clinical application of dental root implant coated with bioglass, Part 1: Procedure of implantation. J Jpn Stomatol Sot 1987; 36: 96-105. Ogiso M, Kaneda H, Shiota M, Mitsuwa T, Wakuda H, Aikawa S, Uoshima K, Masuda T, Kaneda R, Tomizuka K, Tabata T, Sugimoto H. Apatite implant, 2-piece implant system. J Dent Med 1987; 25: 617-33. Kaneko T. Assessment of the interfacial rigidity of bone implants from vibrational signals. J Mater Sci 1987; 22: 3495-502 Takigawa H, Yamauchi M, Nigauri A, Satoh F, Shimizu M, Kawano J. Evaluation of Periotest for prosthetic clinical application. J Jpn Prosthodont Sot 1988; 32: 189-98. Ogiso M, Kaneda H, Shiota M, Mitsuwa T, Wakuda H, Aikawa S, Uoshima K, Masuda T, Kaneda R, Tomizuka K, Ishihara S, Tabata T, Sugimoto H, Kanbayashi H, Matsumoto S, Uehara K, Hidaka T. Apatite P-piece implant, Part 3: Clinical trial. J Jpn Prosthodont Sot 1988;
CaO-PPOS-MgO-SiOs-CaF system glass ceramic tooth implants in monkeys. J Jpn Ass Periodont 1989; 31: 111929. 22. Kamegai T, Nakano H, Seino Y, Ishikawa F. The utilization of acoustoelectric diagnosis in fitting condition at the implantation of bioactive glass coated dental root implant and their clinical estimation. J Jpn Sot Biomater 1990; 8: 2-10.
23. Yamane
S, Shimogoryo R, Tsuda T. Mobility of bon&t and osseointegrated implant before the set of the superstructure. J Jpn Sot Oral Implant01 1990; 3: 19-24. 24. Kudo K, Miyasawa M, Fujioka Y, Kamegai T, Nakano H, Seino Y, Ishikawa F, Shioyama T, Ishibashi K. Clinical application of dental implant with root of coated bioglass: short-term results. Oral Surg Oral Med Oral Path01 1990; 70: 18-23. 25 Iijima T, Takeda T. An observation of chronological change of mobility of IT1 implants with Periotest. J Jpn Sot Oral Implant01 1990; 3: 191-9. 26. Buser D, Weber HP, Lang NP. Tissue integration of nonsubmerged implants: l-year results of a prospective study with 100 IT1 hollow-cylinder and hollow-screw Clin Oral Imp1 Res 1990; 1: 33-40. implants. 27. Olive J, Aparicio C. The Periotest method as a measure Int J Oral of osseointegrated oral implant stability. Maxillofac Implants 1990; 5: 390-400.
28. Kaneko
29.
30.
31.
32: 523-33. S, Nakagawa S, Shimogoryo R, Tsuda T. 13. Yamane Percussion sound of IT1 implant. J Jpn Sot Oral Implant01 1988; 1: 240-4. 14 Kamegai T, Ishikawa F, Nakano H, Seino Y, Fujioka Y, Kudo K, Miyasawa M, Ishibashi K, Shioyama T. Clinical and short term results of dental root applications implantation using materials coated with bioactive glass. In: Kawahara M, ed. Oral Implantology and Biomaterials Amsterdam: Elsevier, 1989, 121-6. of dental root 15. Fujino M, Ogino M. Clinical application implant using bioactive glass. In: Kawahara M, ed. Oral Implantolosy and Biomaterials Amsterdam: Elsevier, 1989, 145-g. T, Sugaya K, Nojima M, Koshihara Y, Haga 16. Takahashi M, Nakagawa K, Hinoide M, Asai Y. Clinical study of Bioceram porous implant. In: Kawahara M, ed. Oral Implantologv and Biomaterials Amsterdam: Elsevier, 1989, 163-8. 17. Saratani K, Yoshida S, Oka H, Kawazoe T. The clinical measurement of the biomechanical mobility of dental implants. In: Kawahara H, ed. Oral Implantology and Biomaterials Amsterdam: Elsevier, 1989, 305-10. S, Shimogoryo R, Tsuda T. Mobility of the 18. Yamane bridge with implant abutments. J Jpn Sot Oral Implant01 1989; 2: 34-8. B, Schulte W. A comparative study of results 19. D’Hoedt with various endosseous implant systems. Int J Oral Maxillofac Implants 1989; 4: 95-105. between acoustic and mechani20. Kaneko T. Comparison cal tapping methods for assessing the interfacial states of bone implants. J Mater Sci 1989; 24: 2820-4. Y, Asano M, Kawanami M, 21. Hongo 0, Mukainakano Kato H. Clinical and histopathological observation of
314
Med. Eng. Phys. 1994, Vol. 16, July
32.
33.
34.
N, Kasahara Y, Kadota H, Fujino M, Senuma S, Sato K. Experimental study on measuring equipment for micro-mobility of dental root implants (Nikon NSP1000). J Jpn Sot Biomater 1990; 8: 287-93. Kaneko T. Assessment of the dental implant-bone J Mater Sci Lett interface from a pulsed microvibration. 1991; 10: 185-7. Matsuda T, Fukuhara H, Fujisaki M, Sugihara K, Onizuka T, Yokota M. Clinical evaluation of a measuring equipment for micro-mobility of dental implant. J Jpn Sot Biomater 1991; 9: 3-l 1. Teerlinck J, Quirynen M, Darius P, Van Steenberghe D. Periotest: an objective clinical diagnosis of bone apposition toward implants. Int J Oral Maxillofac Implants 1991; 6: 55-61. Kaneko T. Pulsed oscillation technique for assessing the mechanical state of the dental implant-bone interface. Biomaterials 1991; 12: 555-60. Sakonaka T, Takeshita F, Akedo H, Morimoto K, Suetsugu T. Mobile examination of Sumicikon and IMZ implant using Periotest. J Jpn Prosthodont Sot 1991; 35: 632-5. Murakami H, Matsuda T, Kishi T, Nashimoto M, Kato T, Tsunosue U. A case report about mobility of implants by PERIOTEST, Part 2: Sumicikon’s PER10 TEST values, distinctions of sex and age. J Jpn Sot Oral Implantol 1991; 4: 221-30.
35. Ichikawa
36. 37.
38.
39.
40.
T, Miyamoto M, Horisaka Y, Okamoto Y, Horiuchi M, Matsumoto N, Yoshida H. Mobility of twopiece apatite implants measured with Periotest and its clinical evaluation. J Jpn Sot Oral Implant01 1992; 5: 51-6. Brunski JB. Biomechanical factors affecting the bonedental implant interface. Clin Mater 1992; 10: 153-201. Yamane S, Shimogoryo R, Tsuda T, Tanaka K. Mobility of Bonelit screw implant. J Jpn Sot Oral Implant01 1992; 5: 223-7. Murakami H, Matsuki K, Nishijima Y, Nakanishi M, Kumonda T, Miyamoto K, Okawa M. A case report about mobility of implants by PERIOTEST, Part 4: Bonefit’s PER10 TEST values. J Jpn Sot Oral Implant01 1992; 5: 240-g. Kishi T, Murakami H, Yamamoto T, Saitou J, Asada K, Shioya H, Nishijima Y, Takagi S. The mobility of implants with PERIOTEST, Part 3: Double head type of SUMICIKON. J Jpn Sot Oral Zmplantol 1992; 5: 250-5. Aparicio C, Branemark P-I, Keller EE, Olive J. Recon-
Stzffness estimated from Periotest: T.M. Kancko
41.
42.
43.
44.
struction of the premaxilla with autogenous iliac bone in Znt J Oral combination with osseointegrated implants. Maxillofac Implants 1993; 8: 61-7. Salonen MAM, Oikarinen K, Virtanen K, Pernu H. Failures in the osseointegration of endosseous implants. Int J Oral Maxillofac Implants 1993; 8: 92-7. K&rig M, Lukas D, Quante F, Schulte W, Topkaya A. zur quantitativen Beurteilung des Messverfahren Schweregrades von Parodontopathien (Periotest). Dtsch Zahtirztl Z 1981; 36: 451-4. D’Hoedt B, Lukas D, Miihlbradt L, Scholz F, Schulte W, Quante F, Topkaya A. Das PeriotestverfahrenEntwicklung und klinische Priifung. Dtsch Zahniirrtl 2 1985; 40: 113-25. Kohno S, Sato T, Tabata T. PERIOTEST - a new measuring instrument of the dynamic periodontal func-
tion and the guide to its application.
Quintessence 1987; 6:
187-95. 45. Schulte W, D’Hoedt B, Lukas D. Miihlbradt L, Scholz F, Bretschi J, Frey D, Gudat H, K&rig M, Marki M, Quante F, Schief A, Topkaya A. Periotest - neues messverfahren Zahniirztl Mitt 1983; 73: der Funktion des Parodontiums. 1229-40. 46. Mishima J. Clinical study of viscosity and elasticity on periodontal tissue: relationship between the conditions of periodontal disease and viscoelasticity of periodontal tissue. J Jjm Stomatol Sot 1973; 40: 367-88. 47. Nagata K. Study of the frequency response of the periodontium. J Jpn Prosthodont Sot 1976; 20: 375-92. 48. Oka H, Yamamoto T, Kawazoe T, Saratani K, Hikida Y. Impact response of periodontal tissues. Med Biol Eng Comput 1988; 26: 260-6.
Med. Eng. Phys. 1994, Vol. 16, July
315