SONOGRAPHYOFALVEOLARRIDGE
for placement of dental implants. As anon-invasive method, the authors prefer ultrasound to ridge mapping, especially because ultrasound provides exact information about the location of the mental foramen and the maxillary sinus. REFERENCES 1. Atwood
DA. Reduction of residual ridges: a major oral disease entity. J PROSTHET DENT 1971;26:266-71. 2. Schwartz MS, Rothman SLG, Rhodes ML, Chafetz N. Computed tomography. Part II: preoperative assessment of the maxilla for endosseus implant surgery. Int J Oral Maxillofac Implants 1987;2:143-8. 3. Wilson EJ. Ridge mapping for determination of alveolar ridge width. Int J Oral Maxillofac Implants 1989;4:41-3.
Determining the force absorption materials used in implant occlusal Roman M. Cibirka, DDS, MS,* Michael Brien R. Lang, DDS, MS,C and Christian
E. Razzoog, S. Stohler,
Spiirlein E., Stein R. Entwicklung einer zweidimensionalen Schiebelehre (Mainzer Modell). 2 Zahniirztl Implantol 1986;2:277-80. Daly CH, Wheeler JB. The use of ultrasonic thickness measurements in the clinical evaluation of the oral soft tissue. Int Dent J 1971;21:418-22. Czembirek H, Frtihwald F, Gritzmann N. Kopf-Halssonographie. 1st ed. Vienna, New York: Springer Verlag, 198867.71. Reprint requests to: DR. MARIO TRAXLER UNIVERSITATSKLINIK FUR ZAHN-, WAHRINGERSTR. 25~, A-1090
MUND-,
UND KIEFERHEILKUNDE
WIEN
VIENNA AUSTRIA
quotient surfaces
for restorative
DDS, MS,b LDS, DrMedDentd
West Bloomfield, Mich., and University of Michigan, Ann Arbor, Mich. It has been hypothesized that the type of material used to form the occlusal surface of restorations retained by dental implants may impart a “dampening effect” to the bone-implant interface. This study compared the force transmitted to human bone by gold, porcelain, and resin occlusal surfaces in a simulated implant occlusal rehabilitation. A Branemark self-tapping implant was placed in a human cadaver mandible with a stacked three element strain gauge cemented to the lingual cortical plate. An Instron testing machine was used to apply an axial force, through a peanut sample, to a restoration that contained interchangeable occlusal surfaces. Applied force was divided by recorded microstrain at the bone-strain gauge junction to derive a calculated ratio, or force absorption quotient. No statistically significant difference of the force absorption quotient between the occlusal surfaces of gold, porcelain, and resin was observed. (J PROSTHET DENT 1992;67:361-4.)
0
cclusalloading of osseointegratedimplants is believed to be a determining factor in the long-term success of an implant treatment pr0gram.l Branemark et a1.2proposed a protocol for occlusal development predicated on basic physics and early clinical results. Their recommendations included acrylic resin asthe material of choice for the occlusal surfacesof implant-retained prostheses. The resiliency of acrylic resin is suggestedasa safeguard
aPrivate practice, West Bloomfield, MI. hAssociate Professor, Department of Prosthodontics. cProfessor and Chair, Department of Prosthodontics. dProfessor of Dentistry, Department of Cariology and General Dentistry. 10/l/33877
THE JOURNAL
OF PROSTHETIC
DENTISTRY
against overstressand microfracture of the implant/bone interface. Although most acrylic resinsare burdened with technical and subjective disadvantages,the alternative of gold or porcelain occlusalsurfacesis describedas not providing resilient safeguarding to the dental implant complex.leg Researchrelated to dental implants has empirically addressedthe subject of occlusalload transfer; however, it is void of studies that quantify, through in vitro human or animal models, force absorption of restorative materials. The present investigation developed a method to scientifically apply and measurethe vertical force usedto incisea food substance.The investigation also recorded the force transmitted to human bone adjacent to an implant fixture when occluding surfaceswere made of gold, porcelain or resin.
361
CIBIRKA
Fig. 1. Schematic diagram of customized stylus assembly with adjustable screw (A) to terminate Instron cycling through power shutdown at contact point (B) of lateral table. Cycle termination was 0.5 mm from specimen(C) retained on the occlusal table CD).
METHODS
AND
MATERIAL
A 3.75 mm x 15 mm Branemark (Nobelpharma USA, Inc., Gothenburg, Sweden) self-tapping endosseous dental implant wasplaced in a human cadaver mandible anterior to the mental foramina, avoiding the symphyseal suture. The bone samplewasmaintained in a humid environment in an effort to minimize desiccation and maintain the in vivo osseouscharacteristics. An en bloc resection of the implant produced the experimental specimen.One stacked three-element 45-degree rosette foil strain gauge of 120 + 0.49%ohm resistancewascementedon the sectioned bone specimen. An Instron universal testing machine@ (Instron Corp., Canton, Mass.) applied quantified axial forces. A 2 cm/min crossheadspeedwasapplied through a customized stylus with a 45-degreecusp incline. Electronic circuitry wasdeveloped to terminate Instron cycling at a describedpoint to avoid crushing the occlusal material sample. The customized stylus externalized the circuit completion, terminating the stroke cycle through an adjustable screwlateral to the occlusaltable. The adjustable screw with an overload spring developed contact between the stylus and lateral horizontal table for circuit completion without placing torque on the system.The sty-
362
ET AL
Fig. 2. Illustration of Instron cycle termination at simultaneouspeanut fracture.
lus terminated its cycle 0.5 mm from contact with the occlusal table (Fig. 1). Occlusalsurfacesamplesof approximately the samesize and dimension were made. Gold (Forticast, Penwalt Jelenko Armonk, N.Y.), porcelain (Optec, Den-Mat Corp., Santa Maria, Calif.), and a dual-cure compositeresin (Visio-Gem, ESPE-Premier, Norristown, PA.) were used. Peanut cubes measuring 8 mm x 3 mm x 3 mm were placed on the occlusalmaterial samplesbefore each individual force application. The foodstuff fractured and imparted a load to the occlusal sample similar to the mechanismof mastication (Fig. 2). An X-Y recorder registered the dynamic bone strains and displayed baseline value deflectionsover time from the strain gaugeelements following bridge excitation through a single-channelsignalconditioning amplifier. Strip graphs of the Instron generated force values, and the recorded microstrain deflections registered at the cortical plate within bone were used for statistical analysis of variance between samples. RESULTS The 10readingsof applied force, output microstrain, and force absorption quotient for each occlusal material are
MARCH
1992
VOLUME
67
NUMBER
3
FORCE
Table
ABSORPTION
QUOTIENT
I. Applied force (Fa), recorded microstrain
(Fs) and force absorption quotients (Fa/Fs) Gold
Resin Fa (l@)
Fs (mm)
Fa/Fs
1.70 2.25 3.97 3.12 1.73 2.38 1.73 2.45 2.75 3.00
58.50 107.00 192.00 139.50 61.50 56.00
0.0291 0.021 0.0207 0.0224 0.0281 0.0425 0.0524 0.0201 0.0297 0.0316
33.00 122.00 92.50 95.00
Fa
(kg/F)
2.25 1.88 2.75 2.37 2.20 3.38 2.38 1.30 1.38 3.25
presented in Table I. The individual force value (Fa) at foodstuff fracbure was divided by the microstrain value (Fs) occurring at the same time to derive a calculated ratio, or force absorption quotient (Fa/Fs). The data was subjected to a one-way analysis of variance (ANOVA) as well as an F-test, which produced a calculated p value. Neither the applied force, the transmitted force, or the force absorption quotient values demonstrated significant differences at the 95% confidence level between the samples of resin, gold, or porcelain. DISCUSSION Biomechanics of an osseointegrated system suggest that forces or moments applied to an implant are modified by the specific implant geometry, material, or design affecting the interfacial load transferred to the surrounding bone.7 In a living specimen, the magnitude of transferred load to osseointegrated implants is thought to initiate a tissue response and stimulate remodeling activity to some degree. Remodeling may be osteogenic or osteoclastic, depending on the biomechanical adaptation of bone to the stimuliWolff s Law.l” Excessive stresses are construed as noxious stimuli and initiate osteoclastic resorptive activity surrounding an implant or the generation of fibrous tissue formation if osseointegration is not complete. Applied force values corresponded with recorded microstrain values in relative magnitude. This finding was attributed to the variations in textural properties of the foodstuff. Data was analyzed to compare the ratio of load input and the force output registered as bone microstrain. It was anticipated that differences of this ratio between the occlusal samples would provide an indication of the degree of dampening, or force absorption, that occurs with commonly used restorative materials. The degree of force absorption, between gold, porcelain, and resin was not considered significant at the 95% confidence level (p 0.5197), which implies that no significant difference in dampening occurred during the experiment. Occlusal forces are assumed to be transferred directly to
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Porcelain
Fs (mm)
Fa/Fs
126.75 78.25 82.50 87.50 61.75 136.50 117.50 60.80 77.00 103.00
0.0178 0.024 0.0333 0.0271 0.0356 0.0248 0.0203 0.0214 0.0179 0.0136
Fa (kg/F)
2.12 2.55 3.12 3.33 1.49 2.83 2.12 1.12 1.33 1.62
Fs (mm)
FalFs
56.50 54.25 106.00 116.00 55.50 179.50 69.75 49.50 67.00 57.50
0.0375 0.047 0.0294 0.0287 0.0268 0.0158 0.0304 0.0226 0.0199 0.0282
the bone across the titanium/bone interface in an osseointegrated implant. l-5 The experimental model was not osseointegrated and cannot be assumed to have developed the intimate apposition of bone defined by the term:*’ Stress may have been (1) dissipated across the interface, (2) absorbed by the impurities resulting from the surgical implantation, or (3) internalized within the titanium, resulting in molecular compression and emitted as heat from the implant to the surrounding bone. During the experiment, an observation was made that the wedging of the fractured peanut against the lateral borders of the occlusal table produced a substantial increase in microstrain. It could be hypothesized that the more complex the occlusal design, the greater the potential for wedging of food and possible increased force transmission to the implant-bone interface. Although a great deal of clinical discussion has occurred regarding the selection of material for the occlusal surface, the results of the present study suggest the need for an understanding of the interaction between occlusal design and force transmission to implant-retained prostheses. CONCLUSIONS This investigation developed a method to apply and measure a vertical force used to incise a food substance placed between an implant and the supporting bone. The method allowed measurement and recording of the vertical force transmitted to bone directly adjacent to the implant. The ratio of the recorded applied load to the force transmitted by the occlusal material surfaces through the implant to bone was used for comparative analysis. The results of this in vivo simulation illustrates no significant difference in force dampening as recorded in bone microstrain between commonly used occlusal materials of gold, porcelain, and resin. REFERENCES 1. Sk&k R. Biomechanical considerations J PROSTHET DENT 1983;49:843-8.
in osseointegrated
prostheses.
363
CIBIRKAETAL
2. Branemark P, Zarb G, Albrektsson T. Tissue integrated prostheses. Chicago: Quintessence Publ, 19%X11-19,117-128,156-162. 3. Brunski J. Biomaterials and biomechanics. Calif Dent J 198&X66-77. 4. Branemark P. Osseointegration and its experimental back ground. J PROSTHET DENT 1983;50:399-410. 5. Adell R, Lekholm U, Branemark P-I. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981;6:381-414. 6. Linder L, Carlsson A, Marsal L, Bjursten LM, Branemark P-I. Clinical aspects of osseointegration in joint replacement: a histologic study of titanium implants. J Bone Joint Surg [Br] 1988;70:550-551. 7. English CE. Implants. Part I. Cylindrical implants. CDAJ 1988;16:17. 8. Caputo A, Standlee JP. Biomechanics in clinical dentistry. Chicago: Quintessence Publ, 1987:216-S.
Effect of hygiene instrumentation A scanning electron microscopy Alan W. Homiak, DDS,a Phillip A. Cook, James DeBoer, DDSc U.S. Army Dental Activity, Fort Bliss, Texas
DDS,b
9. Davis D, Rimrott R, Zarb G. prostheses: part 2. The effect the occlusal superstructure. 10. Perren SM, Cordey J, Rahn rary porosis of bone induced Rel Res 1988;232:139-51.
Studies on frameworks for osseointegrated of adding acrylic resin or porcelain to form Int J Oral Maxillofac Surg 1988;3:275-280. BA, Gamier E, Schneider E. Early tempoby internal fixation implants. Clin Orthop
Reprint requeststo: DR. ROMAN M. CIBIRKA 6177 ORCHARD LAKE ROAD, #120 WEST BLOOMFIELD. MI 48322
on titanium study
abutments:
and
Implant abutments can be exposed to a variety of oral prophylaxis procedures. In this in vitro study, titanium abutments were subjected to five oral prophylaxis treatment modalities; a metal scaler, a plastic scaler, a rubber cup, a rubber cup with tin oxide, and an air-powder abrasive. The abutment surfaces were then examined under both light and scanning electron microscopes. The metal scaler was seen to roughen the titanium surface. All other modalities tested appeared to smooth the titanium surface by removing surface debris and rounding olY the sharp machined grooves present on the untreated abutment surface. (J PROSTHET DENT 1992;67:364-9.)
T
he useof dental implants hasincreasedin recent years. With the advent of the osseointegratedtitanium implant, many patients formerly unable to function with conventional dental prosthesesare now finding success through these implant systems. As with any dental procedure, home oral hygiene practices and professional recall are necessaryif a successful outcome is to be expected. During these visits, an assessment of the implants and surrounding tissues is made,’ and, if needed, the implant abutments receive a prophylaxis. Treatment modifications have been suggestedwhen The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. aMajor, U.S. Army, DC; Senior prosthodontic resident. bColonel, U.S. Army, DC; Director, Prosthodontic Residency Training Program. CColonel, U.S. Army, DC; Assistant Director, Prosthodontic Residency Training Program. 10/l/29672
364
titanium abutments are cleanedcomparedwith the procedures followed when natural teeth are cleaned.For example, the useof metal instruments is contraindicated due to the danger of scratching the titanium surface.im3 Likewise, ultrasonic scalersare not recommendedfor fear that the abutment could be scratched or even loosened by the ultrasonic vibrations.le3 Certain instruments and procedureshave been recommendedfor cleaning titanium surfaces.Instruments made of plastic have beendevelopedto replacemetal scalersand curets.le3The useof a rubber cup, either with1 or without2 abrasives,has also been recommended.Air-powder abrasive systemshave also been mentioned, both in product advertisementsand in the literature, asone of a number of possibletreatment modalities.2 Hand scaling,a rubber cup and abrasive,and air-powder abrasiveshave all beenstudied with respect to the effects that they have upon various tissues and restorative materials.4-13 The effect of various prophylactic modalities on certain titanium implants, especiallyin the mucosalseal area, has also been studied.l4 However, there is currently
MARCH1992
VOLUME67
NUMBER3
for placement of dental implants. As anon-invasive method, the authors prefer ultrasound to ridge mapping, especially because ultrasound provides exact information about the location of the mental foramen and the maxillary sinus. REFERENCES 1. Atwood
DA. Reduction of residual ridges: a major oral disease entity. J PROSTHET DENT 1971;26:266-71. 2. Schwartz MS, Rothman SLG, Rhodes ML, Chafetz N. Computed tomography. Part II: preoperative assessment of the maxilla for endosseus implant surgery. Int J Oral Maxillofac Implants 1987;2:143-8. 3. Wilson EJ. Ridge mapping for determination of alveolar ridge width. Int J Oral Maxillofac Implants 1989;4:41-3.
Determining the force absorption materials used in implant occlusal Roman M. Cibirka, DDS, MS,* Michael Brien R. Lang, DDS, MS,C and Christian
E. Razzoog, S. Stohler,
Spiirlein E., Stein R. Entwicklung einer zweidimensionalen Schiebelehre (Mainzer Modell). 2 Zahniirztl Implantol 1986;2:277-80. Daly CH, Wheeler JB. The use of ultrasonic thickness measurements in the clinical evaluation of the oral soft tissue. Int Dent J 1971;21:418-22. Czembirek H, Frtihwald F, Gritzmann N. Kopf-Halssonographie. 1st ed. Vienna, New York: Springer Verlag, 198867.71. Reprint requests to: DR. MARIO TRAXLER UNIVERSITATSKLINIK FUR ZAHN-, WAHRINGERSTR. 25~, A-1090
MUND-,
UND KIEFERHEILKUNDE
WIEN
VIENNA AUSTRIA
quotient surfaces
for restorative
DDS, MS,b LDS, DrMedDentd
West Bloomfield, Mich., and University of Michigan, Ann Arbor, Mich. It has been hypothesized that the type of material used to form the occlusal surface of restorations retained by dental implants may impart a “dampening effect” to the bone-implant interface. This study compared the force transmitted to human bone by gold, porcelain, and resin occlusal surfaces in a simulated implant occlusal rehabilitation. A Branemark self-tapping implant was placed in a human cadaver mandible with a stacked three element strain gauge cemented to the lingual cortical plate. An Instron testing machine was used to apply an axial force, through a peanut sample, to a restoration that contained interchangeable occlusal surfaces. Applied force was divided by recorded microstrain at the bone-strain gauge junction to derive a calculated ratio, or force absorption quotient. No statistically significant difference of the force absorption quotient between the occlusal surfaces of gold, porcelain, and resin was observed. (J PROSTHET DENT 1992;67:361-4.)
0
cclusalloading of osseointegratedimplants is believed to be a determining factor in the long-term success of an implant treatment pr0gram.l Branemark et a1.2proposed a protocol for occlusal development predicated on basic physics and early clinical results. Their recommendations included acrylic resin asthe material of choice for the occlusal surfacesof implant-retained prostheses. The resiliency of acrylic resin is suggestedasa safeguard
aPrivate practice, West Bloomfield, MI. hAssociate Professor, Department of Prosthodontics. cProfessor and Chair, Department of Prosthodontics. dProfessor of Dentistry, Department of Cariology and General Dentistry. 10/l/33877
THE JOURNAL
OF PROSTHETIC
DENTISTRY
against overstressand microfracture of the implant/bone interface. Although most acrylic resinsare burdened with technical and subjective disadvantages,the alternative of gold or porcelain occlusalsurfacesis describedas not providing resilient safeguarding to the dental implant complex.leg Researchrelated to dental implants has empirically addressedthe subject of occlusalload transfer; however, it is void of studies that quantify, through in vitro human or animal models, force absorption of restorative materials. The present investigation developed a method to scientifically apply and measurethe vertical force usedto incisea food substance.The investigation also recorded the force transmitted to human bone adjacent to an implant fixture when occluding surfaceswere made of gold, porcelain or resin.
361
CIBIRKA
Fig. 1. Schematic diagram of customized stylus assembly with adjustable screw (A) to terminate Instron cycling through power shutdown at contact point (B) of lateral table. Cycle termination was 0.5 mm from specimen(C) retained on the occlusal table CD).
METHODS
AND
MATERIAL
A 3.75 mm x 15 mm Branemark (Nobelpharma USA, Inc., Gothenburg, Sweden) self-tapping endosseous dental implant wasplaced in a human cadaver mandible anterior to the mental foramina, avoiding the symphyseal suture. The bone samplewasmaintained in a humid environment in an effort to minimize desiccation and maintain the in vivo osseouscharacteristics. An en bloc resection of the implant produced the experimental specimen.One stacked three-element 45-degree rosette foil strain gauge of 120 + 0.49%ohm resistancewascementedon the sectioned bone specimen. An Instron universal testing machine@ (Instron Corp., Canton, Mass.) applied quantified axial forces. A 2 cm/min crossheadspeedwasapplied through a customized stylus with a 45-degreecusp incline. Electronic circuitry wasdeveloped to terminate Instron cycling at a describedpoint to avoid crushing the occlusal material sample. The customized stylus externalized the circuit completion, terminating the stroke cycle through an adjustable screwlateral to the occlusaltable. The adjustable screw with an overload spring developed contact between the stylus and lateral horizontal table for circuit completion without placing torque on the system.The sty-
362
ET AL
Fig. 2. Illustration of Instron cycle termination at simultaneouspeanut fracture.
lus terminated its cycle 0.5 mm from contact with the occlusal table (Fig. 1). Occlusalsurfacesamplesof approximately the samesize and dimension were made. Gold (Forticast, Penwalt Jelenko Armonk, N.Y.), porcelain (Optec, Den-Mat Corp., Santa Maria, Calif.), and a dual-cure compositeresin (Visio-Gem, ESPE-Premier, Norristown, PA.) were used. Peanut cubes measuring 8 mm x 3 mm x 3 mm were placed on the occlusalmaterial samplesbefore each individual force application. The foodstuff fractured and imparted a load to the occlusal sample similar to the mechanismof mastication (Fig. 2). An X-Y recorder registered the dynamic bone strains and displayed baseline value deflectionsover time from the strain gaugeelements following bridge excitation through a single-channelsignalconditioning amplifier. Strip graphs of the Instron generated force values, and the recorded microstrain deflections registered at the cortical plate within bone were used for statistical analysis of variance between samples. RESULTS The 10readingsof applied force, output microstrain, and force absorption quotient for each occlusal material are
MARCH
1992
VOLUME
67
NUMBER
3
FORCE
Table
ABSORPTION
QUOTIENT
I. Applied force (Fa), recorded microstrain
(Fs) and force absorption quotients (Fa/Fs) Gold
Resin Fa (l@)
Fs (mm)
Fa/Fs
1.70 2.25 3.97 3.12 1.73 2.38 1.73 2.45 2.75 3.00
58.50 107.00 192.00 139.50 61.50 56.00
0.0291 0.021 0.0207 0.0224 0.0281 0.0425 0.0524 0.0201 0.0297 0.0316
33.00 122.00 92.50 95.00
Fa
(kg/F)
2.25 1.88 2.75 2.37 2.20 3.38 2.38 1.30 1.38 3.25
presented in Table I. The individual force value (Fa) at foodstuff fracbure was divided by the microstrain value (Fs) occurring at the same time to derive a calculated ratio, or force absorption quotient (Fa/Fs). The data was subjected to a one-way analysis of variance (ANOVA) as well as an F-test, which produced a calculated p value. Neither the applied force, the transmitted force, or the force absorption quotient values demonstrated significant differences at the 95% confidence level between the samples of resin, gold, or porcelain. DISCUSSION Biomechanics of an osseointegrated system suggest that forces or moments applied to an implant are modified by the specific implant geometry, material, or design affecting the interfacial load transferred to the surrounding bone.7 In a living specimen, the magnitude of transferred load to osseointegrated implants is thought to initiate a tissue response and stimulate remodeling activity to some degree. Remodeling may be osteogenic or osteoclastic, depending on the biomechanical adaptation of bone to the stimuliWolff s Law.l” Excessive stresses are construed as noxious stimuli and initiate osteoclastic resorptive activity surrounding an implant or the generation of fibrous tissue formation if osseointegration is not complete. Applied force values corresponded with recorded microstrain values in relative magnitude. This finding was attributed to the variations in textural properties of the foodstuff. Data was analyzed to compare the ratio of load input and the force output registered as bone microstrain. It was anticipated that differences of this ratio between the occlusal samples would provide an indication of the degree of dampening, or force absorption, that occurs with commonly used restorative materials. The degree of force absorption, between gold, porcelain, and resin was not considered significant at the 95% confidence level (p 0.5197), which implies that no significant difference in dampening occurred during the experiment. Occlusal forces are assumed to be transferred directly to
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Porcelain
Fs (mm)
Fa/Fs
126.75 78.25 82.50 87.50 61.75 136.50 117.50 60.80 77.00 103.00
0.0178 0.024 0.0333 0.0271 0.0356 0.0248 0.0203 0.0214 0.0179 0.0136
Fa (kg/F)
2.12 2.55 3.12 3.33 1.49 2.83 2.12 1.12 1.33 1.62
Fs (mm)
FalFs
56.50 54.25 106.00 116.00 55.50 179.50 69.75 49.50 67.00 57.50
0.0375 0.047 0.0294 0.0287 0.0268 0.0158 0.0304 0.0226 0.0199 0.0282
the bone across the titanium/bone interface in an osseointegrated implant. l-5 The experimental model was not osseointegrated and cannot be assumed to have developed the intimate apposition of bone defined by the term:*’ Stress may have been (1) dissipated across the interface, (2) absorbed by the impurities resulting from the surgical implantation, or (3) internalized within the titanium, resulting in molecular compression and emitted as heat from the implant to the surrounding bone. During the experiment, an observation was made that the wedging of the fractured peanut against the lateral borders of the occlusal table produced a substantial increase in microstrain. It could be hypothesized that the more complex the occlusal design, the greater the potential for wedging of food and possible increased force transmission to the implant-bone interface. Although a great deal of clinical discussion has occurred regarding the selection of material for the occlusal surface, the results of the present study suggest the need for an understanding of the interaction between occlusal design and force transmission to implant-retained prostheses. CONCLUSIONS This investigation developed a method to apply and measure a vertical force used to incise a food substance placed between an implant and the supporting bone. The method allowed measurement and recording of the vertical force transmitted to bone directly adjacent to the implant. The ratio of the recorded applied load to the force transmitted by the occlusal material surfaces through the implant to bone was used for comparative analysis. The results of this in vivo simulation illustrates no significant difference in force dampening as recorded in bone microstrain between commonly used occlusal materials of gold, porcelain, and resin. REFERENCES 1. Sk&k R. Biomechanical considerations J PROSTHET DENT 1983;49:843-8.
in osseointegrated
prostheses.
363
CIBIRKAETAL
2. Branemark P, Zarb G, Albrektsson T. Tissue integrated prostheses. Chicago: Quintessence Publ, 19%X11-19,117-128,156-162. 3. Brunski J. Biomaterials and biomechanics. Calif Dent J 198&X66-77. 4. Branemark P. Osseointegration and its experimental back ground. J PROSTHET DENT 1983;50:399-410. 5. Adell R, Lekholm U, Branemark P-I. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981;6:381-414. 6. Linder L, Carlsson A, Marsal L, Bjursten LM, Branemark P-I. Clinical aspects of osseointegration in joint replacement: a histologic study of titanium implants. J Bone Joint Surg [Br] 1988;70:550-551. 7. English CE. Implants. Part I. Cylindrical implants. CDAJ 1988;16:17. 8. Caputo A, Standlee JP. Biomechanics in clinical dentistry. Chicago: Quintessence Publ, 1987:216-S.
Effect of hygiene instrumentation A scanning electron microscopy Alan W. Homiak, DDS,a Phillip A. Cook, James DeBoer, DDSc U.S. Army Dental Activity, Fort Bliss, Texas
DDS,b
9. Davis D, Rimrott R, Zarb G. prostheses: part 2. The effect the occlusal superstructure. 10. Perren SM, Cordey J, Rahn rary porosis of bone induced Rel Res 1988;232:139-51.
Studies on frameworks for osseointegrated of adding acrylic resin or porcelain to form Int J Oral Maxillofac Surg 1988;3:275-280. BA, Gamier E, Schneider E. Early tempoby internal fixation implants. Clin Orthop
Reprint requeststo: DR. ROMAN M. CIBIRKA 6177 ORCHARD LAKE ROAD, #120 WEST BLOOMFIELD. MI 48322
on titanium study
abutments:
and
Implant abutments can be exposed to a variety of oral prophylaxis procedures. In this in vitro study, titanium abutments were subjected to five oral prophylaxis treatment modalities; a metal scaler, a plastic scaler, a rubber cup, a rubber cup with tin oxide, and an air-powder abrasive. The abutment surfaces were then examined under both light and scanning electron microscopes. The metal scaler was seen to roughen the titanium surface. All other modalities tested appeared to smooth the titanium surface by removing surface debris and rounding olY the sharp machined grooves present on the untreated abutment surface. (J PROSTHET DENT 1992;67:364-9.)
T
he useof dental implants hasincreasedin recent years. With the advent of the osseointegratedtitanium implant, many patients formerly unable to function with conventional dental prosthesesare now finding success through these implant systems. As with any dental procedure, home oral hygiene practices and professional recall are necessaryif a successful outcome is to be expected. During these visits, an assessment of the implants and surrounding tissues is made,’ and, if needed, the implant abutments receive a prophylaxis. Treatment modifications have been suggestedwhen The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. aMajor, U.S. Army, DC; Senior prosthodontic resident. bColonel, U.S. Army, DC; Director, Prosthodontic Residency Training Program. CColonel, U.S. Army, DC; Assistant Director, Prosthodontic Residency Training Program. 10/l/29672
364
titanium abutments are cleanedcomparedwith the procedures followed when natural teeth are cleaned.For example, the useof metal instruments is contraindicated due to the danger of scratching the titanium surface.im3 Likewise, ultrasonic scalersare not recommendedfor fear that the abutment could be scratched or even loosened by the ultrasonic vibrations.le3 Certain instruments and procedureshave been recommendedfor cleaning titanium surfaces.Instruments made of plastic have beendevelopedto replacemetal scalersand curets.le3The useof a rubber cup, either with1 or without2 abrasives,has also been recommended.Air-powder abrasive systemshave also been mentioned, both in product advertisementsand in the literature, asone of a number of possibletreatment modalities.2 Hand scaling,a rubber cup and abrasive,and air-powder abrasiveshave all beenstudied with respect to the effects that they have upon various tissues and restorative materials.4-13 The effect of various prophylactic modalities on certain titanium implants, especiallyin the mucosalseal area, has also been studied.l4 However, there is currently
MARCH1992
VOLUME67
NUMBER3
