This document summarizes a study that evaluated the outcomes of oral implants placed in bone with limited bucco-oral dimensions over a 3-year period. 100 implants were placed in 28 patients. The study found that the implants had a 100% survival rate over 3 years and that the marginal bone levels around the implants remained stable. The results indicate that implants can successfully be placed in sites with up to 4.5mm of bucco-oral bone width without the need for bone grafting, providing patients maintain good oral hygiene.

1. Good morning

2. THE OUTCOME OF ORAL IMPLANTS
PLACED IN BONE WITH LIMITED
BUCCO-ORAL DIMENSIONS: A 3-YEAR
FOLLOW-UP STUDY
Temmerman A et al.
J Clin Periodontol 2015
Shilpa Shivanand
II MDS

3. Introduction
• The clinical success of an implant partially depends on several
external factors  primary implant stability, bone quality,
time of loading, infection control, surgical technique and
height and width of the alveolar bone.
• Primary implant stability is determined by the properties of
the bone that contribute to its strength.
• Implant micro-movements within a range of 50–150 μm
seem to be acceptable for optimal bone healing
Szmukler-Moncler et al 1998

4. 4
Parts Of A Dental Implant
IMPLANT BODY
COLLAR
ABUTMENT SCREW
FIXATION SCREW
LAB ANALOGUE

5. Inter Implant Distance
• Atleast 1mm of bone on all the 4 sides.
1mm 1.0-1.5 mm
1mm
1mm
1mm
1mm

7. • Inter-arch space:
For fixed implant-supported
prosthesis:
 7 mm - in the posterior region
 8-10 mm - in the anterior areas.
 An implant-retained removable
prosthesis requires at least 12
mm.
8-10mm
12 mm
7mm

8. Adjacent teeth:
• At least 7 mm between two
adjacent teeth.
• Adjacent teeth must be
infection free:
 all restorative, periodontal,
and endodontic procedures
should be completed prior to
implant planning.
7 mm
7 mm

9. • The defining factors for bone quality are trabecular thickness,
mineral density and micro-architecture
Ribeiro-Rotta et al 2007
• In relation to time of loading, a recent review showed no
differences in marginal bone level changes between different
loading protocols
Suarez et al 2013
• However, the length of the implant seems of interest for the
survival rate of most implant systems.

10. • Since implant survival decreases when the implant is shorter
than 7 mm
Pommer et al 2011
• To determine the health of the peri-implant tissues a
radiological assessment of the marginal bone level around the
shoulder of an implant is a reliable option
Grusovin et al 2008

11. • To consider an implant as successful, it has to meet criteria
with respect to tissue physiology (osseointegration), function
(mastication), absence of pain and user satisfaction
Tonetti & Palmer 2012
• In 1986, Albrektsson et al stated that a mean marginal bone
loss of 1.5 mm after the first year of loading is acceptable.

12. • More recent studies show a mean marginal bone loss of 1.0
mm after the first year of loading and in the following years
an annual 0.1 mm additional bone loss
Cecchinato et al 2008
• Some papers indicate that the bone thickness around an
implant should be at least 1 or 2 mm to assure long-term
success and bone coverage
Esposito et al 2007, Grunder et al 2005

13. Aim
• This prospective follow-up study aims to evaluate the
radiological interproximal bone changes of oral implants
placed in sites with ≤ 4.5 mm of bucco-oral bone width.

14. Material and Methods
• This prospective, single-centre study was carried out at the
Department of Periodontology of the University Hospitals
Leuven.
• All oral implants (Astra Tech, Dentsply Implants, M€olndal,
Sweden) were placed in the period between 2009 and 2010.

15. Inclusion criteria
• Implant sites with ≤4.5 mm bone in bucco-oral dimensions, as
measured on CBCT cross-sectional images (2-mm subcrestally)
• Only those patients, with a very limited bucco-oral dimension
over the crest were included.
• Patients expectations were pure functional, without any
severe aesthetical demand.

16. • All implant sites were analysed on a multi-slice CT (Somatom
Plus S, Siemens, Erlangen, Germany) or cone-beam CT
(Scanora 3D, Soredex, Tuusula, Finland).
• The implants were placed according to the surgical protocol
provided by the implant company (Instruction manual, Astra
Tech, DentsplyImplants, M€olndal, Sweden).
• However, in most cases, the surgical protocol was changed
accordingly to the situation.

17. • The amount of buccal bone on the implant was <1 mm at
each implant site.
• Whenever a fenestration or dehiscence occurred, a GBR
procedure was performed.
• A thin layer of “deproteinized bovine bone matrix” (Bio-
OssTM, Geistlich, Switzerland) was used and covered with a
resorbable collagen membrane (Bio-GideTM, Geistlich,
Switzerland).
• The digital intra-oral radiographs (follow-up) were obtained

18. Marginal bone level changes
• The intra-oral, long-cone radiographs were taken at: implant
placement, functional loading, 1, 2 and 3-years follow-up.
• The distances, in millimetres, between the shoulder of the
implant and the first clear bone-to-implant contact were
recorded both mesially and distally.
• The thread pitch distance and the full length of the implant
were also recorded.

19. • These measurements (accuracy of 0.01 mm) were performed
with a software program (IMAGE J, NIH, Bethesda, Maryland,
USA).
• The measurements were initially made in a pixel format.
• Linear distance measurement (mm) could be retrieved after
calibration of the images according to the respective thread
pitch distance, provided by the manufacturer.
• The full length of the implant was used for the conversion.

20. Width of the alveolar process
• The width of the alveolar process on the future implant
osteotomy sites was measured, pre-operatively, on cross-
sectional images of the conebeam
• CT or multi-slice CT, using the software tool to the nearest 0.1
mm (PACS lightbox, IMPAX pacs, Agfa).
• Measurements were made at the top of the crest and at every
2 mm (2, 4, 6, 8, 10 and 12 mm below the first measurement).

21. Clinical case with intra-oral radiographs
showing the bone level after 3 years of loading.

22. Results- Patient and implant data
• A total of 28 patients (three males and 25 females) were
included.
• A total of 100 implants were placed (13 in males, 87 in
females). Two in one patient with diabetes and seven in two
patients with a history of radiotherapy outside the head and
neck region.

23. • Eighty-eight per cent of the implants were placed in the upper
jaw and 12% in the lower jaw, primarily in the region between
the 2nd incisor and 2nd premolar.

24. • All implants had a diameter of 3.5 mm and their length ranged
from 8 mm to 15 mm.
• The majority of the implants had a length of 13 mm (45%) or
11 mm (33%). The mean width of the future osteotomy at the
top of the crest was 2.8 mm (SD: 0.8;range [1.1; 4.4]).

25. • None of the implants were placed in extraction sockets.
• The mean submerged healing period was 3.6±0.9 months.

26. Marginal bone level changes
• The implants were primarily placed subcrestally (mesially:
0.94 mm±0.87, and distally: 0.68 mm±0.97 below bone level).
• At abutment connection the marginal bone was located 0.65
±0.6 mm apically of the implant shoulder (mesially 0.63 ±0.7
mm, distally 0.67 ±0.6).
• One, 2 and 3 years after final abutment connection, this
“bone level” was slightly more apically (0.80, 0.84 and 0.79
mm apically to the implant shoulder, respectively).

27. Marginal bone level changes

28. Discussion
• The results of this prospective clinical follow-up study
demonstrated that the interproximal bone changes for
implants placed in sites with ≤ 4.5 mm of bucco-oral bone
width were stable during the 3 years of functional loading.
• Furthermore, the implant survival rate was 100%.
• The marginal bone changes around implants are most
common, between abutment connection and the first year of
functional loading.

29. • The present study showed a mean marginal bone loss of 0.17
mm ±0.40 in the first year of functional loading.
• After the first year the marginal bone loss varied a bit with
after 2 years a marginal bone loss increase with another 0.05
mm ±0.37 and after 3 years a marginal bone loss decrease
with 0.06 mm ±0.14.

30. • The bucco-oral bone width is considered to be crucial for
osseointegration and even more important for an aesthetic
outcome.
• In the literature there are some guidelines available which
suggested a zone of 1.5–2 mm of bone around the implant
Esposito et al 2007, Grunder et al 2005

31. • Small-diameter implants have become a popular treatment
option to avoid bone augmentation procedures and more
complex surgery.
• In some studies, implants with a width of 3.5 mm are
considered small diameter implants
Sohrabi et al 2012
• Other studies consider small diameter implants as those with
a width ≤3.3 mm
Ortega-Oller et al 2014

32. • A recent (systematic/narrative) reviews concluded that the
survival rates small-diameter implants are similar to those
reported for standard width implants
Hasan et al 2014, Sohrabi et al 2012
• The present study indicates that bone grafting procedures can
be avoided when sites with ≤4.5 mm of bucco-oral bone width
are available.

33. • All patients included in the study, were following a very strict
maintenance protocol and as a result had a high level of oral
hygiene.
• This might not be the best reflection of an average patient in
the daily practice.

34. Conclusion
• Within the limits of this study, it can be concluded that
implants placed in sites with limited dimensions (≤4.5 mm
vestibule-oral) can be successful for a period of 3 years,
comparable to implants placed in wider alveolar crests.
• This effect could be explained by the microthreads in the
conical and marginal part of the implant system used as well
as by the special drilling sequence avoiding bone
compression.
• These results showed that if patients are not ready for bone
grafting procedures this treatment option could be a good
alternative.

35. CROSS REFERENCE

36. I. Survival rates of short (6 mm) micro-rough surface
implants: a review of literature and meta-analysis
Srinivasan M et al , Clin Oral Implants Res 2014
OBJECTIVE:
• The aim of this review was to test the hypothesis that 6 mm
micro-rough short Straumann implants provide predictable
survival rates and verify that most failures occurring are early
failures.
MATERIALS AND METHODS:
• A PubMed and hand search was performed to identify studies
involving micro-rough 6-mm-short implants published
between January 1987 and August 2011. Studies were
included that (i) involve Straumann(®) 6 mm implants placed
in the human jaws, (ii) provide data on the survival rate, (iii)
mention the time of failure, and (iv) report a minimum follow-
up period of 12 months following placement.

37. RESULTS:
• From a total of 842 publications that were screened, 12
methodologically sound articles qualified to be included for
the statistical evaluation based on our inclusion criteria.
CONCLUSION:
• This meta-analysis provides robust evidence that micro-rough
6-mm-short dental implants are a predictable treatment
option, providing favorable survival rates. The failures
encountered with 6-mm-short implants were predominantly
early and their survival in the mandible was slightly superior.

38. II. Failure rates of short (≤ 10 mm) dental implants and
factors influencing their failure: a systematic review
Sun HL , Int J Oral Maxillofac Implants.2011
PURPOSE:
• The aim of this study was to evaluate the long-term failure
rates of short dental implants (≤ 10 mm) and to analyze the
influence of various factors on implant failure.
MATERIALS AND METHODS:
• The PubMed and Cochrane Library databases were consulted
for follow-up studies published between the years 1980 and
2009. For those studies that met the inclusion and exclusion
criteria, data concerning the number of implants (≤ 10 mm)
placed and lost and any related risk factors were gathered in
tables and subjected to analysis. Univariate and multivariate
analyses were performed.

39. RESULTS:
• The heterogeneity and low quality of the included studies made
meta-analysis impossible. A total of 35 human studies fulfilled the
criteria. There was a tendency toward higher failure rates for the
maxilla and for dental implants with a machined surface compared
with the mandible.
CONCLUSIONS:
• Among the risk factors examined, most failures of short implants
can be attributed to poor bone quality in the maxilla and a
machined surface. Although short implants in atrophied jaws can
achieve similar long-term prognoses as standard dental implants
with a reasonable prosthetic design according to this review,
stronger evidence is essential to confirm this finding.