An Analysis of 2235 Implants Placed in a Private Periodontal Practice

By: Dr. Murray L. Arlin D.D.S., dip. Perio, F.R.C.D.(C)

INTRODUCTION
How can a dentist in private practice, know how to optimize successful results in Implant Dentistry?
This paper will address the above question and will focus on the information gained from implants placed in a private periodontal practice setting, and restored with using the team approach. A dental implant management software system called “TRITON DIMS”¹, which can generate many types of reports including LIFETABLE REPORTS, will be highlighted. The Lifetable Reports in particular, display data that is invaluable in allowing the practitioner to identify factors that have a significant impact on implant survival. Some representative clinical examples will also be presented.

SOURCES OF INFORMATION

When dentists evaluate a product or technique, they may rely on published data and/or clinical experience. The importance of clinical experience is invaluable, however the contemporary dentist should, as much as possible, carry out clinical treatment based on sound scientific evidence. This has been referred to as “EVIDENCE BASED DECISION MAKING”. Published studies can be ranked for scientific validity and it is generally agreed that double-blind placebo-controlled trials are the strongest. Longitudinal and cross sectional studies that do not incorporate a double blinding study design are weaker and clinical case reports are considered to be weaker still. Private practice studies are usually clinical case reports, or may be longitudinal type studies. However, when ranking different types of studies for their scientific validity and clinical applicability, there are other significant issues to consider.

¹Triton Dims - Designed and owned by Martin Lumish, 1487 Westview Dr., Yorktown Hts., N.Y. 10598,
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STUDIES (FUNDED) BY IMPLANT COMPANIES

In the field of Implant Dentistry, published studies are often financed, supervised and analyzed by a supporting implant manufacturer. Obviously there can be a potential conflict of interest with these types of studies. Many would agree that it is not in the best interest of the implant manufacturer (that supports the study), to publish data that would reflect poorly on their product. While accusations are not being made, it is possible that a study might: a) only enlist the “best” clinicians, b) delete the data from the poor clinicians and/or centers, c) not account for all implants placed, d) not include high risk patients and/or high risk implant sites, e) not describe a part of the study protocol that might artificially optimize a successful appearing result (eg. - not counting implants that were removed at initial placement because they were considered “risky”, eg. not extremely stable). In summary, the astute clinician should have an attitude of “healthy skepticism” when confronted with potentially biased studies or data!

STUDIES (NON-FUNDED) CARRIED OUT IN PRIVATE PRACTICE

Compared to funded institutional studies, private practice non-funded studies potentially have advantages as well as disadvantages. An advantage is that the operating conditions of the study, and therefore the results of the study, may be more likely to be applicable to other private practice dentists’ operating environment.. A disadvantage is that there may be more financial and time restraints present in the private practice setting. Thus it is unlikely that the private practice dentist could institute a strict study design protocol, that would totally control for bias and the multitude of variables encountered. As a result, it is extremely rare to see a double-blind placebo controlled study carried out in private practice. Another challenge for the private practice dentist and/or staff is to document, analyze and report all the data in a scientifically meaningful way. This challenge can be more easily met if all the relevant data is recorded on an appropriate computer program.
Without computer assistance, it is difficult to imagine, how any large database can be properly managed. With the extremely large number of variables in the field of Implant Dentistry, the process of data collection and analysis becomes extremely challenging. Compounding this difficulty, is that as improvements in products and techniques result in higher implant survival rates, it become progressively more difficult to recognize significant differences of smaller magnitudes. Thus when one embarks on a process of detailed documentation and analysis, it becomes obvious that an appropriate computer software system is essential, if one is committed to attain the full potential value of the data.

With contemporary implant dentistry, it is not uncommon to see reports of high survival rates. One could then get the impression that achieving an additional small incremental increase in implant survival (eg. 2%), might not be clinically relevant. However analyzing survival rates from another perspective, if the survival rate increased from 96% to 98%, a reduction in failures of 50% would have been achieved. In private practice, every failure represents a traumatic experience for both the patient and the dentist. The serious clinical investigator should therefore continually evaluate and modulate clinical protocol in an effort to achieve the best possible results. In summary, contemporary Implant Dentistry should be “evidence based” as much as possible. The value of data from private practice can be immensely enhanced, when it is documented and analyzed in a scientific and clinically meaningful way.
With contemporary implant dentistry, it is not uncommon to see reports of high survival rates. One could then get the impression that achieving an additional small incremental increase in implant survival (eg. 2%), might not be clinically relevant. However analyzing survival rates from another perspective, if the survival rate increased from 96% to 98%, a reduction in failures of 50% would have been achieved. In private practice, every failure represents a traumatic experience for both the patient and the dentist. The serious clinical investigator should therefore continually evaluate and modulate clinical protocol in an effort to achieve the best possible results. In summary, contemporary Implant Dentistry should be “evidence based” as much as possible. The value of data from private practice can be immensely enhanced, when it is documented and analyzed in a scientific and clinically meaningful way.

CONDITIONS OF THE AUTHOR’S PRIVATE PRACTICE STUDY

This article reports on every implant the author has placed and recorded on the TRITON DIMS-dental implant management software system (up to the time of submission of this article). The author has no direct financial or contractual obligation to any of the implant systems or to TRITON DIMS. It is suggested that the information presented in this article is non-biased.
All of the surgical aspects of the treatment were carried out by the author in his private practice. Local anaesthetic only was used , and aseptic surgical technique was incorporated .While it is not within the scope of this article to describe the details of the surgical protocol, certain significant issues do warrant being mentioned. Reasonable clinical judgment and informed patient consent were instituted at all times, however patients and/or procedural protocols, that presented a higher risk of implant failure, were not necessarily excluded! With patient selection for example, heavy smokers were advised of the higher risk of implant failure. They were given smoking cessation options, but were treated even if they continued smoking. As well, sites exhibiting very poor bone quality and quantity were often treated (see Lifetable # 7). With procedural protocol for example, certain “risky” treatments were also undertaken but only where clinical circumstances warranted the risk. For example, in selected cases, when a failed implant was removed, an “immediate implant replacement technique” was carried out (see Lifetable #16). Although this latter technique was associated with a higher risk of implant failure, it was deemed warranted at times because the ease and convenience of the procedure, outweighed the associated risks. Thus in the author’s private practice, the primary concern was treating all patients in a way that was judged to be in their best interests. The practitioner’s concern about the overall survival statistics did not take precedence over the patient’s best interests. As a result, some of the clinical decisions and treatments carried out, (as in the above examples) resulted in the lowering of the author’s overall survival rate statistics.
The restorative treatment and most of the supportive maintenance care, was carried out by a large number of private practice dentists who had varying degrees of experience. The results presented in this article may reflect what a private practice dentist working with the “team approach” could experience, but only if treatment conditions were identical. For example the different implant survival rates presented in the Lifetables of this article, are applicable only to the exact implant type used at that time. It is noteworthy that some implant surfaces have undergone significant change, compared to some of the implant surfaces presented in the Lifetables of this article. It should not be assumed for example, that all hydroxyapatite surfaces are equivalent. As well every dentist, practice environment, laboratory and patient are not identical, and therefore there is no guarantee that other dentists will experience the same results. However, despite these issues, the author suggests data obtained from a particular private practice can still be of value to other private practitioners. The challenge in a private practice as mentioned before, is to document, analyze and present the data (with the help of a computer program), in a way that it can be easily understood by other dentists. A brief description of the TRITON DIMS is included so that readers will have a better understanding of the information that follows.

TRITON DIMS

It is not within the scope of this article to describe TRITON DIMS in detail. More information on the program can be obtained by contacting the author. TRITON DIMS is a relational database program and entries are made onto the system at the time each implant is placed, and as well at every follow up visit. The system allows an easily expandable and almost unlimited number of attributes that can be applied to a large number of implant variables. Once data is entered, the TRITON DIMS system can easily generate many different reports. In this article one of these reports will be primarily highlighted, namely the “LIFETABLE ANALYSIS”.


LIFETABLES (See Lifetable Analysis #1: SAMPLE LIFETABLE.)

The LIFETABLES in this article, represent only a small sample of the reports that can be generated from the TRITON DIMS data base, however the author has attempted to select specific examples that represent potentially significant and interesting results.
In a LIFETABLE, the implant subjects are placed in groups based on the actual follow up time . For example, a patient treated 5 years ago, but only seen most recently at 2½ years following initial implant placement, would be categorized in the “2 to 3” year follow up period in the LIFETABLE. Patients may not be followed up for a number of reasons other than implant failure. Perhaps the biggest challenge in private practice is to motivate the completed and satisfied implant patient to return for regular follow up examinations. In the author’s personal experience, this has been especially challenging as many patients return to their general dentist exclusively for all of their follow up care. It is critical nevertheless, to persevere in trying to have patients come in for regular follow up care, not only for their own benefit, but as well LIFETABLE statistics (and in particular cumulative survival rates) become increasingly more meaningful, as larger numbers of patients are followed up for longer time periods.
A cumulative survival rate (Csr) should only be presented together with a lifetable. The assumption is that the subset of patients who returned for follow up, can accurately represent the whole group. Thus the cumulative survival rate (Csr) is a prediction of what the true survival rate would be if all the patients eventually returned for follow-up, for that particular time period. Conclusions are more valid however if 75% or more of the whole group has been followed up. A correctly set-up lifetable should allow the reader to draw his or her own conclusions.
Lifetable Analysis Table #1: Sample Lifetable
Time Period.....Patients......Implants......Lost.....Sr-%.......Csr-%
0-1 Years......45.................100.............5...........95.0......95.0
1-2 Years......40.................90...............3...........96.7......91.8 (95.0x96.7)
2-3 Years.......29.................75..............1...........98.7......90.6 (91.8x98.7)
3-4 Years.......18.................40..............0.........100.0.....90.6 (90.6x100.0)
4-5 Years........4..................10..............0.........100.0.....90.6 (90.6x100.0)

In this particular article, all the LIFETABLES are presenting survival statistics, thus abbreviations on the LIFETABLES, Sr = implant survival rate and Csr = implant cumulative survival rate. For more information, readers are referred to two newsletters from NobelBiocare: a) 1992, Vol. 6, #1, pg. 7 and b) 1995, Vol. 9, #1, pg. 6.
LIFETABLE ANALYSIS # 2: All Implants

All of the implants placed by the author span up to a 10 -11 year follow up period, utilizing 5 different implant systems. In the first 5 years Core-Vents (currently Paragon Implant Company) were primarily placed. In the ensuing time period the majority of implants placed were Steri-Oss, with a significant number of Straumann ITI implants. Fewer numbers of implants from the Branemark, 3i and Lifecore systems had also been placed.



Lifetable Analysis #2 - All Implants
Time Period............Patients..........Implants.........Lost.............Sr-%.......Csr-%
0 Years.............. 776................... 2235.................. 46...........97.9.......97.9
0-1 Years........... 662.................... 1883.................. 47...........97.5.......95.5
1-2 Years........... 516.................... 1498.................. 13............99.1.......94.7
2-3 Years........... 425.................... 1223.................. 3..............99.8.......94.4
3-4 Years........... 343.................... 978.................... 2..............99.8.......94.2
4-5 Years........... 276.................... 794.................... 5..............99.4.......93.6
5-6 Years........... 215.................... 636.................... 8...............98.7......92.5
6-7 Years........... 153.................... 446.................... 1...............99.8......92.3
7-8 Years........... 105.................... 331.................... 2...............99.4......91.7
8-9 Years........... 66...................... 221.................... 0...............100.......91.7
9-10 Years......... 31...................... 102.................... 0...............100.......91.7
10-11 Years....... 14...................... 46...................... 0...............100.......91.7
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage



LIFETABLE ANALYSIS #3: All Maxillary Implants

Almost half of the total number of implants of implants were placed in the maxilla. The survival rate in the maxilla

compared favorably to the mandible. Several published studies, that have used an exclusive implant system, have

reported significantly lower success rates in the maxilla compared to the mandible. In the author’s practice,

perhaps the availability of several implant systems and a wider range of implant types and sizes accounted for the results.

Lifetable Analysis #3: All Maxillary Implants
Time Period.........Patients..........Implants.........Lost...........Sr-%.......Csr-%
0Years...............442...................1063...........11.............99.0...........99.0
0-1 Years........... 369.................... 882............18.............98.0............96.9
1-2 Years........... 285.................... 706.............11............98.4............95.4
2-3 Years........... 235.................... 556..............0.............100.............95.4
3-4 Years........... 188.................... 427..............1..............99.8...........95.2
4-5 Years........... 155.................... 357..............1..............99.7...........94.9
5-6 Years........... 129.................... 305..............7...............97.7...........92.8
6-7 Years........... 93...................... 215..............1...............99.5...........92.3
7-8 Years........... 64...................... 150...............2..............98.7...........91.1
8-9 Years........... 36...................... 87.................0..............100............91.1
9-10 Years......... 16...................... 37.................0..............100............91.1
10-11 Years....... 5........................ 11.................0..............100............91.1
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years =After 2nd stage





LIFETABLE ANALYSIS #4: All Mandibular Implants
Slightly more than half of the total number of implants were placed in the mandible. Implants were placed both in anterior and posterior sites exhibiting varying degrees of bone quality and quantity. In the mandible, a larger proportion of titanium and a smaller proportion of hydroxyapatite implants were placed, compared to the maxilla. This may explain why the mandible exhibited a somewhat lower incidence of “late” failures. See Lifetables #,s 8,9 and 10 for a more in-depth analysis of this issue.

Lifetable Analysis #4: All Mandibular Implants
Time Period.......Patients........Implants.......Lost..........Sr-%........Csr-%
0 Years............... 414..........1172................35............97.0............97.0
0-1 Years........... 355...........1001...............29............97.1............94.2
1-2 Years........... 278............792..................2............99.7............94.0
2-3 Years........... 227............667..................3............99.6............93.5
3-4 Years........... 188.............551.................1............99.8............93.4
4-5 Years........... 148............437...................4...........99.1............92.5
5-6 Years........... 111.............331..................1...........99.7............92.2
6-7 Years........... 77...............231...................0.........100.............92.2
7-8 Years........... 56...............181...................0.........100.............92.2
8-9 Years........... 39...............134...................0.........100.............92.2
9-10 Years......... 21.................65...................0..........100.............92.2
10-11 Years....... 11.................35....................0........100.............92.2
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage






LIFETABLE ANALYSIS # 5: “Excellent” Bone Quality and Quantity- All Implant Types
Bone quality and quantity was subjectively judged at the time of implant placement (see Table #18). Excellent bone

Quality (“A”) was typically associated with very stable initial implant placement. Excellent bone quantity (“1or 2”)

was typically associated with placement of implants with diameters of 3.7mm or greater, and lengths of 13mm or

greater. The results indicated that bone quality and quantity were important determinants for implant survival.



Lifetable Analysis # 5 : “Excellent” Bone Quality and Quantity (“A-2”) - All Implant Types
Time Period........Patients.......Implants........Lost.........Sr-%...........Csr-%
0 Years...............76...............119.............2...............98.3.............98.3
0-1 Years............62...............100.............1...............99.0.............97.3
1-2 Years........... 52.................88...............0..............100.............97.3
2-3 Years........... 45.................81...............0..............100.............97.3
3-4 Years........... 37.................69...............0..............100..............97.3
4-5 Years........... 30.................54...............0..............100..............97.3
5-6 Years........... 21.................43...............0...............100.............97.3
6-7 Years........... 14.................25...............0...............100.............97.3
7-8 Years........... 10.................18...............0...............100.............97.3
8-9 Years........... 10..................18...............0..............100............97.3
9-10 Years......... 4....................5.................0..............100............97.3
10-11 Years....... 2....................2................0...............100............97.3
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage

Bone quality and quantity was subjectively judged at the time of implant placement (see Table #18).
Fair bone Quality (“B or C”) was typically associated with stable initial implant placement. Fair bone quantity (“3”)
was typically associated with placement of implants with diameters of 3.25mm to 3.8mm, and lengths of 10mm to

13mm. The results indicated that bone quality and quantity were very important determinants for implant survival.


Lifetable Analysis # 6 : “Fair” Bone Quality and Quantity (“B-3”) - All Implant Types

Time Period............... Patients.......Implants........Lost............Sr-%.......Csr-%
0Years............... 209................334................3................99.1...........99.1
0-1 Years........... 162................268................8.................97.0............96.1
1-2 Years........... 122................207................1.................99.5...........95.7
2-3 Years........... 95..................161................1.................99.4...........95.1
3-4 Years........... 66...................115................0................100............95.1
4-5 Years........... 49...................87...................0................100...........95.1
5-6 Years........... 36...................67...................0................100...........95.1
6-7 Years............23...................45...................1................97.8..........95.1
7-8 Years........... 17...................36...................0...............100............93.0
8-9 Years........... 10...................23...................0................100...........93.0
9-10 Years......... 6.....................13....................0..............100............93.0
10-11 Years....... 3.....................5......................0...............100...........93.0
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage



LIFETABLE ANALYSIS # 7: “Poor” Bone Quality and Quantity (“D-4”)- All Implant Types
Bone quality and quantity was subjectively judged at the time of implant placement (see Table #18).

Poor bone Quality (“D”) was typically associated with barely stable initial implant placement. Poor bone quantity (“4”) was

typically associated with placement of implants with diameters of 3.25mm to 3.8mm, and lengths of 6mm to10mm.

The results indicated that bone quality and quantity were very important determinants for implant survival.


Lifetable Analysis # 7 : “Poor” Bone Quality and Quantity- All Implant Type

Time Period............... Patients........... Implants........... Lost..........Sr-%......Csr-%
0 Years.............. 80...................... 121.................... 7................94.2,,,,,,,,,,,,94.2
0-1 Years,,,,,,,,,,, 66...................... 99...................... 8................91.9.............86.6
1-2 Years........... 46...................... 70...................... 7................90.0.............77.9
2-3 Years........... 33......................42...................... 1................97.6.............76.1
3-4 Years........... 23...................... 26...................... 1.................96.2............73.2
4-5 Years........... 18...................... 20...................... 1.................95.0.............69.5
5-6 Years........... 15...................... 17...................... 0.................100..............69.5
6-7 Years........... 11...................... 13...................... 0.................100...............69.5
7-8 Years........... 8.......................10....................... 0..................100..............69.5
8-9 Years........... 5........................ 5........................ 0...................100.............69.5
9-10 Years......... 1........................ 1........................ 0...................100.............69.5
*Sr = Survival rate*Csr = Cumulative survival rate *0 Years = Before 2nd stage*0-1 Years = After 2nd stage


LIFETABLE ANALYSIS # 8: Titanium Threaded “Screw Vent” Implants
The Screw-Vent implant was originally introduced by the Core-Vent Corporation, which is currently the

Paragon Implant Company . While this implant has undergone some modifications since its introduction,

the endosseous threaded macrostructural design was, and still is based on the original Branemark titanium screw.
The data shows that only 1 implant had been lost beyond the one year time period following initial implant placement,

indicating a “steady state” had been reached. This “steady state” pattern of survival is consistent with the data

published in many long term studies with the Branemark implant.


Lifetable Analysis # 8 : Titanium Threaded “Screw Vent” Implants


Time Period............... Patients........... Implants........... Lost.........Sr-%.........Csr-%
0 Years............... 161.................... 435.................... 9................97.9............97.9
0-1 Years........... 155.................... 414.................... 15..............96.4............94.4
1-2 Years........... 150.................... 392.................... 1................99.7............94.1
2-3 Years............143.................... 379.................... 0................100.............94.1
3-4 Years........... 133.................... 351.................... 0................100.............94.1
4-5 Years........... 113.................... 317.................... 0................100.............94.1
5-6 Years........... 89...................... 256.................... 0................100.............94.1
6-7 Years........... 70...................... 200.................... 0................100.............94.1
7-8 Years........... 58...................... 172.................... 0................100.............94.1
8-9 Years........... 41...................... 133.................... 0................100.............94.1
9-10 Years......... 18...................... 59...................... 0................100.............94.1
10-11 Years....... 7........................ 22...................... 0.................100............94.1
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage

LIFETABLE ANALYSIS # 9: HA Coated 3.25mm Narrow Diameter “Micro-Vent” Implants
The narrow diameter Micro-Vent implant was originally introduced by the Core-Vent Corporation, which is

currently the Paragon Implant Company. This implant has recently undergone significant design changes, notably

changing from a straight walled design to a tapered design. In this article the original straight walled design has

been documented. This implant mostly has ledges rather than threads, and is primarily pushed rather than

threaded into the recipient site. The Micro-vent mid-portion is coated with hydroxyapatite. These implants
seemed to be associated with a low early, but “ongoing” failure rate. Under the specific conditions of this study,
this particular implant did not seem to reach a “steady state” and additional analysis of the data (not shown in

this article) indicated further implant loss is anticipated.


Lifetable Analysis # 9 : HA Coated 3.25mm Narrow Diameter “Micro-Vent” Implants
Time Period............... Patients........... Implants........... Lost..........Sr-%....Csr-%
0 Years............... 98...................... 197.................... 2................99.0.........99.0
0-1 Years........... 96...................... 192.................... 1................99.5.........98.5
1-2 Years........... 94...................... 189.................... 7................96.3.........94.8
2-3 Years........... 93...................... 182.................... 1................99.5.........94.3
3-4 Years........... 91...................... 179.................... 2.................98.9........93.2
4-5 Years........... 83...................... 161.................... 0.................100.........93.2
5-6 Years........... 72...................... 140.................... 6..................95.7........89.3
6-7 Years........... 48...................... 82...................... 0..................100.........89.3
7-8 Years........... 28...................... 42...................... 0..................100.........89.3
8-9 Years........... 11...................... 16...................... 0...................100........89.3
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage


LIFETABLE ANALYSIS # 10: HA Coated 4.25mm Wide Diameter “Micro-Vent” Implants

The wide diameter Micro-Vent implant was originally introduced by the Core-Vent Corporation, which is currently the Paragon Implant Company. This implant has recently undergone significant design changes, notably changing from a straight walled design to a tapered design. In this article the original straight walled design has been documented. This implant mostly has ledges rather than threads, and is primarily pushed rather than threaded into
the recipient site. The Micro-Vent mid-portion is coated with hydroxyapatite. These implants seem to be associated
with a low early, but “ongoing” failure rate. Under the specific conditions of this study, this particular implant did not seem to reach a “steady state” and additional analysis (not shown in this article) has indicated further implant loss is anticipated.


Lifetable Analysis # 10 : HA Coated 4.25mm Wide Diameter “Micro-Vent” Implants
Time Period............... Patients........... Implants........... Lost........Sr-%.......Csr-%
0 Years............... 50...................... 74...................... 0..............100........100
0-1 Years........... 49...................... 73...................... 0...............100........100
1-2 Years........... 47...................... 70...................... 1...............98.6.......98.6
2-3 Years........... 47...................... 69...................... 1...............98.6.......97.1
3-4 Years........... 46...................... 67...................... 0................100.......97.1
4-5 Years........... 43...................... 64...................... 5................92.2......89.6
5-6 Years........... 37...................... 52...................... 2.................96.2.....86.1
6-7 Years........... 24...................... 32...................... 1.................96.9......83.4
7-8 Years........... 10...................... 14...................... 0.................100......83.4
8-9 Years 2........................ 4........................ 0.................100......83.4
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage



LIFETABLE ANALYSIS # 11: Steri-Oss Implants - All Types
The author achieved a higher survival with this system compared to the overall average. There may be several
explanations to account for this. The author had almost 5 years of experience prior to starting with this system. As well, this implant system is extremely versatile in that a wide variety of implant sizes and types are available. By
carrying a large inventory of implant sizes and types, the author was able to choose the specific implant that best
suited the implant site, thus likely enhancing the chances for implant initial stability, short and long term survival.



Lifetable Analysis # 11 : Steri-Oss Implants - All Types


Time Period............... Patients........... Implants........... Lost.................. Sr-%................Csr-%
0 Years............... 329.................... 930.................... 17...................... 98.2................... 98.2
0-1 Years........... 254.................... 710.................... 19...................... 97.3................... 95.5
1-2 Years........... 150.................... 464.................... 2........................ 99.6................... 95.1
2-3 Years........... 88...................... 270.................... 1........................ 99.6................... 94.8
3-4 Years........... 43...................... 146.................... 0........................ 100.................... 94.8
4-5 Years........... 21..................... 68...................... 0........................ 100.................... 94.8
5-6 Years........... 6........................ 28...................... 0........................ 100.................... 94.8
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage


LIFETABLE ANALYSIS # 12: Steri-Oss Implants - 3.8mmHL Diameter Titanium Threaded
The Steri-Oss 3.8mmHL is similar to a Branemark implant in terms of the prosthetic platform and endosseous
macrostructural design. Although not identical in the thread design, titanium grade and surface treatment, in some
respects the threaded titanium portion of the implant is comparable to the Branemark and titanium Screw-Vent.
As with the titanium threaded Branemark and Screw-Vent designs, there were no “late” failures and a “steady state”
seems to have been achieved.



Lifetable Analysis # 12 : Steri-Oss Implants - 3.8mmHL Diameter Titanium Threaded
Time Period............... Patients........... Implants........... Lost........Sr-%.....Csr-%
0 Years............... 99...................... 202.................... 2..............99.0.......99.0
0-1 Years........... 87...................... 177.................... 7..............96.0.......95.1
1-2 Years........... 61...................... 139.................... 1..............99.3.......94.4
2-3 Years........... 41...................... 100.................... 0...............100.......94.4
3-4 Years........... 16...................... 53...................... 0...............100.......94.4
4-5 Years........... 7........................ 15...................... 0...............100.......94.4
5-6 Years........... 2........................ 6........................ 0................100.......94.4
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage


LIFETABLE ANALYSIS # 13: Steri-Oss Implants - 3.25 Small Diameter Titanium Threaded
Typically narrow diameter implants were placed when the width of the osseous recipient ridge was 5.5mm or less.

Despite the relatively narrow ridge, the survival rate compared favorably to wider implants. There have not been any implant fractures to date despite many anterior single tooth restorations. This may be due in part to the titanium
alloy composition. The favorable results may also reflect overall case selection, selective bone augmentation

procedures and stabilization in cortical bone. As with the titanium threaded Branemark and Screw-Vent designs, there were no “late” failures and a “steady state” seems to have been achieved.




Lifetable Analysis # 13 : Steri-Oss Implants - 3.25mm Small Diameter Titanium Threaded
Time Period.............. Patients........... Implants........... Lost........Sr-%.......Csr-%
0 Years............... 109.................... 205.................... 4..............98.0........98.0
0-1 Years........... 92...................... 176.................... 4..............97.7........95.8
1-2 Years........... 62...................... 130.................... 1...............99.2.......95.1
2-3 Years........... 42...................... 92...................... 0..............100........95.1
3-4 Years........... 17..................... 40...................... 0..............100........95.1
4-5 Years........... 8........................ 24...................... 0...............100........95.1
5-6 Years........... 3........................ 13...................... 0...............100.......95.1
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage


LIFETABLE ANALYSIS # 14: Straumann ITI Implants - All, Single Stage and TPS Coated
The Straumann ITI system had been used almost exclusively in posterior sites, which as a result may have presented a higher frequency of sites, with relatively poorer bone quantity and/or quality. Despite this, the survival rates with this system exceeded all other systems. **One particular patient accounted for 60% (6 out of 10) of all ITI failures**. If this one patient was not included in the analysis, the survival rate would have been greater than 98%. As with the titanium threaded Branemark, Screw-vent and Steri-Oss designs,“late” failures were not seen. It is noteworthy that the ITI implant surface was unlike the aforementioned designs in that it had a TPS coating.



Lifetable Analysis # 14 : Straumann ITI Implants - All, Single Stage and TPS Coated
Time Period............... Patients......Implants..........Lost.......Sr-%......Csr-%
0 Years............... 117.................... 287..................9**.........96.9......96.9
0-1 Years........... 90...................... 227..................1............99.6......96.4
1-2 Years........... 50...................... 142..................0............100......96.4
2-3 Years........... 32...................... 102..................0.............100......96.4
3-4 Years........... 8........................ 34....................0.............100......96.4
4-5 Years........... 2........................ 5......................0..............100......96.4
5-6 Years........... 1....................... 2.....................0..............100......96.4
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage



LIFETABLE ANALYSIS # 15: Immediate Extraction Socket Placement- All Implant Types

Implant placement immediately after extraction accounted for over 15% of all implants placed. Most implants were titanium threaded designs replacing single rooted teeth, with anterior sites being more frequent than bicuspid sites. The survival rates compared very favorably to implants placed in healed sites. In most immediate implant cases, relatively wider and longer implants were placed, as the recipient site had not undergone post extraction ridge resorption. A strict patient selection and surgical protocol were adhered to. In the majority of cases, guided bone regeneration was not carried out, yet osseous fill of any existing peri-implant space was seen in almost all cases.


Lifetable Analysis # 15 : Immediate Extraction Socket Placement- All Implant Types

Time Period............... Patients........... Implants........... Lost.......Sr-%......Csr-%
0 Years............... 211.................... 358.................... 3............99.2........99.2
0-1 Years........... 172.................... 305.................... 8.............97.4.......96.6
1-2 Years........... 121................... 223.................... 2.............99.1.......95.7
2-3 Years........... 100.................... 183.................... 0.............100........95.7
4-5 Years........... 78...................... 152.................... 0..............100.......95.7
5-6 Years........... 54...................... 110.................... 0..............100.......95.7
6-7 Years........... 36...................... 78...................... 0..............100.......95.7
7-8 Years........... 20...................... 47...................... 0..............100.......95.7
8-9 Years........... 12...................... 30...................... 0...............100......95.7
9-10 Years......... 6........................ 11...................... 0...............100......95.7
10-11 Years....... 1........................ 1........................ 0...............100.....95.7
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage



LIFETABLE ANALYSIS # 16: Failed Implant-Immediate Replacement- All Implant Types
In a small number of cases, failed implants were removed and wider and/or longer implants were immediately placed in the same sites. This technique was only considered in selected cases, where for example one of the prerequisites was that the failed implant had to be associated with minimal peri-implant bone loss. Although the small number of cases limits the reliability of any conclusions, the prognosis for success with this particular technique seems drastically reduced. One should also take into account, that the “risky” nature of this procedure may be compounded by the likelihood, that the initial implant failed because there were preexisting risk factors.

Although this latter technique was associated with a higher risk of implant failure, it was deemed warranted at times,
because the ease and convenience of the procedure, outweighed the associated risks.

Lifetable Analysis # 16 : Failed Implant-Immediate Replacement- All Implant Types

Time Period............... Patients........... Implants........... Lost......Sr-%......Csr-%
0 Years............... 15...................... 19..................... 4...........78.9........78.9
0-1 Years........... 9........................ 13...................... 3...........76.9........60.7
1-2 Years........... 5........................ 7........................ 0...........100.........60.7
2-3 Years........... 5........................ 7........................ 0............100........60.7
3-4 Years........... 3........................ 5........................ 0............100........60.7
4-5 Years........... 1....................... 3........................ 0.............100.......60.7
5-6 Years........... 1........................ 3........................ 0.............100.......60.7
6-7 Years........... 1........................ 3........................ 0.............100.......60.7
7-8 Years........... 1........................ 3........................ 0.............100.......60.7
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage


LIFETABLE ANALYSIS # 17: Failed Implant-Delayed Replacement- All Implant Types
In some cases, failed implants were removed and after 3 or more months of healing, new implants were placed in the same site. Although the small number of cases limits the reliability of any conclusions, the prognosis for success
of this particular technique seems to be significantly reduced. One should also take into account, that the “risky” nature of this procedure may have been compounded by the likelihood, that the initial implant failed because there were preexisting risk factors.

Life Table Analysis # 17 : Failed Implant Replacement - Delayed (>3 months) - All Implant Types

Time Period............... Patients........... Implants........... Lost........Sr-%.......Csr-%
0 Years.............. 7........................ 13...................... 2..............84.6.......84.6
0-1 Years........... 5........................ 8........................ 0..............100........84.6
1-2 Years........... 3........................ 5........................ 0..............100........84.6
2-3 Years........... 2........................ 4........................ 0..............100........84.6
3-4 Years........... 1........................ 3........................ 0...............100.......84.6
4-5 Years........... 1........................ 3........................ 0...............100.......84.6
5-6 Years........... 1........................ 3........................ 0...............100.......84.6
6-7 Years........... 1........................ 3........................ 0...............100.......84.6
7-8 Years........... 1........................ 3........................ 0................100.......84.6
8-9 Years........... 1........................ 1........................ 0................100.......84.6
*Sr = Survival rate *Csr = Cumulative survival rate *0 Years = Before 2nd stage *0-1 Years = After 2nd stage



TablTable # 18: Bone Quality/Quantity Distribution-All Implant Types
(“A”= greatest density, “D” =least density, “1”= greatest volume, “4” = least volume)
Quality Quantity................A.............B.................C................D.............TOTAL
.......................1.................47............44..............22................6..................116
.......................2................. 119.........374...........160.............32..................685
.......................3................. 113.........334...........514.............74...............1,040
.......................4...................37............104...........132...........121..................394
.........................TOTAL.........316..........853...........833...........233............2,235

# 19: Patient Age at Implant Placement
Age Interval.............................................Number of Patients
15-30...................................................................... 78
31-40...................................................................... 93
41-50...................................................................... 163
51-60...................................................................... 209
61-70...................................................................... 150
70+......................................................................... 83
Average=51..............................................Total = 776

Table # 20: Prosthesis Types

Single Fixed Crown......................................................... 287
Splinted Fixed Crown & Bridge..................................... 271
Cantilevered Fixed Crown & Bridge............................. 59
Bar Overdenture............................................................. 60
Single Overdenture......................................................... 150
Splinted Implant to Natural Tooth.................................. 10

Summary
This article has presented the results that the author has obtained with dental implants, placed in his private practice, in a format that may be of value to others. Hopefully additional private practice studies (that can add valuable and practical information for private practice dentists) will be published to go along with other types of published studies and research.


*Note to the editor: The bulleted information and the captions that follow are not an official part of the article as outlined in this document, but rather you need to typeset the following captions with the slides that I have sent to you via courier.

Please remove radiographs from the fixture mounts when you are photographing them as the slide mounts crop the borders of the radiographs.
If you will be cropping any of the enclosed photographs, then if possible, I would like to view them before they are published. Please crop the single histological slide so as to highlight the implant & surrounding bone.
It is important that the slides be grouped together in the layout of the article “by case”, ie. there are 9 cases with anywhere from 2 to 6 slides per case.
Please return all Kodachromes and radiographs to me as soon as you are finished with them.
Please make available to me, as many reprints of this article as possible. If there will be no extra charge, I would like as many as 500, or whatever number you can arrange.

Captions that accompany the illustrations
Case I - #1: Steri-Oss machined acid etched threaded titanium implants
Panoramic view taken immediately after initial placement of 16 implants. The most distal implant site at the patient’s upper right, demonstrated the poorest bone quality and quantity.
Case I - #2: Steri-Oss machined acid etched threaded titanium implants
At 6 weeks following initial implant placement, the most distal implant on the patient’s upper
right exhibited obvious mobility and was removed.
Case I - #3: Steri-Oss machined acid etched threaded titanium implants
Occlusal view of the final prosthesis after 2 years in function. The implants were fitted with custom
abutments and the full arch splinted bridge was transitionally cemented.
Case I - #4: Steri-Oss machined acid etched threaded titanium implants
Periapical radiograph of the upper right posterior area taken 3 years after the prosthesis insertion. Sinus bone grafting was declined, thus limiting the available bone in the area of the only failed implant.
Case II - #1: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
The patient exhibited a missing maxillary left second bicuspid, first and second molar. A partial upper denture and sinus bone grafting were both declined and the patient desired a minimum of 2 additional “fixed” teeth.
Case II - #2: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
Two implants were placed, in the maxillary left second bicuspid and first molar sites. The crowns were splinted and careful attention was paid to the occlusion and biomechanical force distribution.
Case II - #3: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
This periapical radiograph was taken shortly after prosthetic restoration. The available bone in the first molar site only allowed for placement of an 8 mm. length implant.
Case II - #4: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
This periapical radiograph was taken five years after prosthetic restoration. Note the long term stable crestal bone level despite the limited bone quantity at the first molar site.
Case III - #1: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
Competed implant prosthesis in centric occlusion. The distal unit was designed as a cantilever pontic which was joined to the 2 implants anteriorly. The pontic was adjusted to have no centric or excursive occlusal contacts.
Case III - #2: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
Periapical radiograph taken shortly after prosthetic insertion. Sinus osseous grafting was declined and thus only a 7 mm. length implant was placed at the second bicuspid site.
Case III - #3: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
The distal implant was lost after 9 months in function and a new prosthesis was fabricated. Poor bone quality and quantity, prosthetic design and overloading, likely caused this “late” implant failure.
Case III - #4: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
An attempt was made to minimize overloading to the implant, by designing the occlusion with cuspid rise in left lateral excursion however rigid splinting of the “implant to natural tooth” should have been avoided, by placing additional implants.


Case IV - #1: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
Clinical view of the mandibular posterior 4 unit splinted prosthesis at 10 years post insertion. The abutments and suprastructure were cemented.
Case IV - #2: Core-Vent (currently Paragon) acid etched titanium threaded Screw Vent implants
Periapical radiograph taken 10½ years after initial implant placement, demonstrating extremely
stable crestal bone levels, ie. a “steady state” seems to have been achieved.
Case V - #1: Branemark machined titanium threaded implants
Lower right single tooth implant in the first molar site demonstrating extremely stable crestal bone levels after 8 years in function, ie. a “steady state” seems to have been achieved.
Case V - #2: Branemark machined titanium threaded implants Lower left single tooth implant in the first molar site demonstrating extremely stable crestal bone levels after 8 years in function, ie. a “steady state” seems to have been achieved.
Case VI - #1: Core Vent (currently Paragon) hydroxyapatite coated wide (4.25 mm) diameter Microvents
Radiograph taken shortly after prosthetic insertion of a 2 unit screw retained, porcelain fused to metal splinted suprastructure.
Case VI - #2: Core Vent (currently Paragon) hydroxyapatite coated wide (4.25 mm) diameter Microvents
Radiograph taken 4 years after initial prosthetic insertion. The severe bone loss had developed on an ongoing basis, ie. a “steady state” had not been achieved.
Case VI - #3: Core Vent (currently Paragon) hydroxyapatite coated wide (4.25 mm) diameter Microvents
Clinical view taken 4 years after initial prosthetic insertion, corresponding to the previous radiograph.
The deep pockets exhibited suppuration upon probing.
Case VI - #4: Core Vent (currently Paragon) hydroxyapatite coated wide (4.25 mm) diameter Microvents Radiograph taken 4¼ years after initial prosthetic insertion illustrating further bone loss. One implant had already been lost and the second implant was removed shortly thereafter.



Case VII - #1: Core Vent (currently Paragon) hydroxyapatite coated (4.25 mm) and (3.25 mm) diameter Microvents
Periapical radiograph taken 2 years after initial placement illustrating advanced bone loss at the middle 4.25 mm diameter Microvent
Case VII - #2: Core Vent (currently Paragon) hydroxyapatite coated (4.25 mm) and (3.25 mm) diameter Microvents
Clinical view with the prosthetic suprastructure removed. Note the “peri-implant acute abscess” associated with the middle implant.
Case VII - #3: Core Vent (currently Paragon) hydroxyapatite coated (4.25 mm) and (3.25 mm) diameter Microvents
Periapical radiograph taken 7 years after explantation of the middle implant. The mesial and distal implants had not exhibited significant crestal bone loss.
Case VII - #4: Core Vent (currently Paragon) hydroxyapatite coated (4.25 mm) and (3.25 mm) diameter Microvents
Clinical view of the new prosthesis 7 years after initial implant placement. Despite the loss of 1 implant, the remaining 2 implants allowed the fabrication of an acceptable new prosthesis.
Case VIII - #1: Core Vent (currently Paragon) machine acid etched titanium threaded Screw Vent and ITI Straumann TPS coated solid screw
Periapical radiograph taken shortly after placement of three 3.7 mm diameter Screw Vent Implants. There were no initial indications that any implants would not osseointegrate.
Case VIII - #2: Core Vent (currently Paragon) machine acid etched titanium threaded Screw Vent and ITI Straumann TPS coated solid screw
Six months after initial implant placement, despite lack of obvious bone loss, the mesial implant apparently failed as it could be unscrewed with minimally applied counter-torqueing force.
Case VIII - #3: Core Vent (currently Paragon) machine acid etched titanium threaded Screw Vent and ITI Straumann TPS coated solid screw
Periapical radiograph taken 2 years after the “immediate replacement” of the 3.7 mm diameter Screw Vent with a 4.1 mm diameter Straumann ITI solid screw. Crestal bone levels were stable.
Case VIII - #4: Core Vent (currently Paragon) machine acid etched titanium threaded Screw Vent and ITI Straumann TPS coated solid screw
Clinical view illustrating a single tooth screw retained crown on the Straumann ITI implant and
a 2 unit screw retained splint on the remaining 2 Screw Vent implants.
Case IX - #1: Branemark machined titanium threaded implant
Periapical radiograph of the implant just two weeks after restoration. The implant exhibited obvious
bone loss, mobility and deep pockets (which has been atypical for machined titanium implants).
Case IX - #2: Branemark machine titanium threaded implant
The failed implant was easily removed and the “socket” was thoroughly curetted. As the circum-ferential bone was intact, adjunctive regenerative materials were not employed.
Case IX - #3: Branemark machine titanium threaded implant
Histological analysis of the removed implant revealed a continuous layer of soft tissue interposed between the bone and the implant, indicating osseointegration likely never occurred initially.
Case IX - #4: Branemark machine titanium threaded implant
Periapical radiograph taken 1 year after removal of the failed implant. Note the mm grid lines which helped to measure the bone more accurately in the mesio-distal and apico-coronal dimensions.
Case IX - #5: Branemark machine titanium threaded implant
Periapical radiograph taken 5 years after restoration of the “delayed” implant replacement. The
excellent crestal bone level indicates a “steady state” had been achieved.
Case IX - #6: Branemark machine titanium threaded implant
Clinical view of the Cera-One prosthetic restoration.