journal club Evaluation of Hard and Soft Tissue Dimensions Around Zirconium Oxide Implant–Supported Crowns: A 1-Year Retrospective Study Kniha at el , J Periodontol 2016;87:511-518.

1. Evaluation of Hard and Soft Tissue Dimensions Around
Zirconium Oxide Implant–Supported Crowns: A 1-Year
Retrospective Study
Kniha at el , J Periodontol 2016;87:511-518.
PRESENTED BY
DR RIPUNJAY KR TRIPATHI
POST GRADUTE STUDENT
DEPT OF PERIODONTOLOGY

2. Aim
To evaluate the effect of the distance between the alveolar crest of a full-ceramic implant to
the lowest point of the contact area of the crowns on the interdental papilla.

3. Introduction
A recent multicenter study reveals the need for a methodology that allows the unbiased and metric assessment of implant- related soft and hard tissue dimensions.
Several soft and hard tissue landmarks around an implant are important for the evaluation of dimensional changes occurring in the periodontium and alveolar bone.
These points include the first crestal bone contact to the implant, the lowest point of the interdental contact zone of the crowns, and the top of the interdental papilla.
At present, there exists no clearly defined non-invasive methodology that allows the precise and reproducible measurement of the distances between these land- marks to describe the
patient’s individual soft and hard tissue topography.

4. Materials And Methods
Patients and Methodology
This study included 117 patients.
A year after the prosthetic rehabilitation of each implant, 87 patients (35 males and 52 females, aged
21 to 80 years; mean age: 55 years at time of implant placement) agreed to participate in the
methodologic assessment.
A total of 16 patients had 2 adjacent implants, therefore, 125 implants were included in the study.

5. The exclusion criteria were as follows:
Systemic Disease (E.G., Uncontrolled Diabetes)
Mucosal Disease
Untreated Periodontitis
Gingivitis
No Contact Point Between The Crowns
Endodontic LesionsOr
Severe Bruxism Or Clenching Habits.

6. Implant Design
Full-ceramic zirconia monotype implants, each with a diameter of 4.1 mm, were used.
The implants were available in the lengths of 8, 10, and 12 mm and in two different abutment heights
of 4.0 and 5.5 mm.
All radiographs were taken with the digital x-ray sensor parallel and the x-ray beam perpendicular to
the proximal area between the teeth.
To use the crown length as calibration for the computerized measurement on the clinical picture, its
height was recorded with a divider, and height values were taken from a millimeter ruler.

7. Identification of the Tip of the Soft Tissue Papilla Formation in Dental Radiographs
and Dependent Distance Measurements
To visualize the tip of the papilla formation on radiographs, a tiny volume of temporary
cement mixed with tungsten powder (1:1) was placed in the interdental space at the top
of the papilla during the 1-year measurement.
With this radiodense marker,
the right-angled standardized x-ray image
demonstrated a very clear and
sharply delineated negative image of the interdental papilla

8. Against this background, the defined distance of 0.8 mm from one implant thread to the other
was used for calibration of the measurement on the radiographic images.
To reduce calibration errors, the calibration was based on the distance between five
consecutive threads, representing a total length of 4 mm.

9. Direct Distance Measurements During Examination of the Patient and Evaluation of Clinical
Images
During the examination of the patient, the length of the clinical crown (distance 1) was obtained with a
divider and used for calibration of the clinical images.
The crown length was defined as the shortest distance from the upper gingival zenith to the end of the
crown.
To measure the distances
from the papilla tip to the lowest point
of the contact zone between
the clinical crowns (distance 2),
a thin wire loop (0.09-mm diameter)
was interdentally placed under tension.

10. Statistical Analyses
Statistical analyses were performed with software
Spearman r test.

11. Results
Reproducibility of the Individual Measurements
To evaluate the reproducibility of the individual measurements, a dental implant was randomly
selected to have the clinical and radiologic analysis of the distances repeated 10 times.
Every repetition was performed on a different day and at a different time.

13. Examples of Different Clinical Situations With Description of the Respective Distance Measurements
Depending on the clinical situation, the most interesting surrogate parameter for the papilla deficit (distance
2) may vary considerably.
Figure 4A shows an example of a very desirable outcome, whereas Figure 4B shows a slightly less satisfying
result, with a papilla deficit between 0 and 0.6 mm.
In Figure 4C, the appearance of this deficit does not create the perception of an empty interdental space. It
still represents a satisfying result, with the remaining distance 2 lying between 0.6 and 2 mm.
The esthetically undesirable appearance of a black triangle is shown in Figure 4D. In such cases, distance 2
has a length of >2 mm.

15. Distance Between the Alveolar Crest at the Implant to the Lowest Point of the Contact Area of the
Crowns in Relation to the Papilla
Deficit (Distance 4)
When the measurement from the contact point of the crest of the bone at the implant was < 5 mm, the papilla
was present in 100% of cases.
When the distance was 10 mm, the papilla was present in 67% of cases, without any visible deficit.

16. All patients were distinguished into four groups according to the papilla deficit:
group 1 = no deficit
group 2 = deficit >0 and <0.6 mm
group 3: deficit greater or equal to0.6 and <2 mm and
group 4 = deficit of greater or equal to2 mm.

17. Discussion
Tarnow et al. and Choquet et al. showed that the distance from the top of the crestal bone to
the lowest point of the contact zone of the crowns determines the height potentially available
for papilla formation.
Kan et al. described the relationship of the interproximal bone level next to the adjacent teeth
as the major cause.The main problem is to exactly define the lowest point of contact within
the overlapping area of the crown outlined in the clinical radiographs.
The soft tissue analysis usually followed the pink esthetic score rating,

18. Jemt distinguished groups of patients with missing papillae, less than half of the papilla,
more than half of the papilla, full papilla, and hyperplastic papilla.
According to them, a remaining distance in the interdental area in the sense of a black
triangle is realized by dentists when it is greater or equal to 2 mm laypersons recognize it at
3 mm and up.

19. CONCLUSIONS
To visualize these landmarks, the authors suggest the use of interdental ligatures showing
the hidden lowest point of the contact zone of the crowns and the use of a very dense
temporary cement mixture containing tungsten powder
The critical distance between the bone crest at the implant and contact point in relation to a
full papilla may be greater than that previously described in the literature.

20. Thank you