A Six-Month Clinical Study to Evaluate the Effects of Sodium Trip-olyphosphate and Tetrapotassium Pyrophosphate Based Calculus Dissolution Oral Rinse in Patients with Zirconium Dioxide and Titanium Dental Implants

Aim: To clinically evaluate the effects of a novel anti-calculus mouth rinse containing sodium tripolyphosphate and tetrapotassium pyrophosphate (Periogen, USA) on development of gingivitis and plaque around dental implants versus control over a period of six months. Material and methods: This was a randomized, 6 month, parallel groups, double blind, single center clinical trial. Forty subjects with present dental implants (22 zirconium dioxide and 20 titanium) were randomly assigned to one of two subgroups: control group (regular brushing) and test group (regular brushing followed by using the calculus dissolution based oral rinse). All subjects were assessed with gingival index (GI), plaque index (PI) and Volpe-Manhold calculus index (VMI) after 3 and 6 months. Results: Statistical analysis found that test group in both zirconium dioxide and titanium group demonstrated statistically significant lower GI, PI and VMI scores. Conclusion: This study demonstrates that calculus dissolution based Periogen® mouthrinse provided clinically significant reduction in calculus formation in subjects with zirconium dioxide and titanium dental implants when used twice daily for 6 months as an adjunct to toothbrushing.


INTRODUCTION
A dental implant is an artificial tooth root that interfaces with the bone of the jaw or skull through dynamic process of osseointergation to hold a replacement tooth or prosthetic bridge.Dental implants are considered to be safe treatment options for missing tooth or teeth subject to proper case selection and placement technique.
Review of literature on peri-implant soft tissue around zirconia showed that zirconia dioxide implants and abutments provide a very good peri-implant soft tissue interface that achieved an irritation-free attachment.[3][4][5][6] In vitro experimental studies on zirconium showed favorable response in terms of adhesion and proliferation of various cellular components of connective tissue suggesting zirconium as a material of choice for perio-integration. 7Results of Degidi et al. study showed a lower inflammatory response in biopsies from peri-implant soft tissue around zirconium healing caps when compared to titanium. 8he greatest biological challenge that affects implants longevity is poor plaque control and deposition of calculus around dental implants leading to host induced inflammatory response.Dental implants and their components act as a scaffold on which bacteria can accumulate and form bacterial biofilm which can lead to peri-implantitis.It is the most common causes of dental implant failure. 9It has been concluded that zirconia surface accumulate significantly less bacteria when comparable with titanium ones [10][11][12] The progress of science and technology leading to new products development that eradicate the reservoir of bacteria i.e. dental calculus seems to be perfect scientific strategy to add longevity to dental implants and their healthy existence in oral cavity.Calculus dissolution based oral rinse Periogen, (Periogen Company USA), presents significantly potential oral rinse for suppressing the mineralization of dental plaque into calculus. 14A six month comparative study by Saini R proved that Perio-gen® is clinically proven to prevent tartar/calculus build-up 45% more effectively than brushing alone on new supragingival calculus formation. 13n the current literature there is no study of clinical effect of calculus dissolution around dental implants.The aim of this study was to evaluate the efficacy of calculus dissolution based oral rinse (Periogen ® ) in patients with zirconium dioxide and titanium dental implants placed in lower jaw for long-term effects on prevention of peri-implantitis.

MATERIALS AND METHODS
The present study was performed in the Dental department of Advance Europe Medical Centre, UAE, after approved from the research and ethical committee of Ras al-Khaimah Medical and Health Sciences University (RAKMHSU), UAE, vide no.3-2014-FD.
Forty patients present with one or more dental implant in posterior part of lower jaw were analyzed in this study.Twenty patients were treated with zirconium dioxide dental implants (Axis Biodental, Switzerland), polyetherketoneketone (PEKK) abutments and full ceramic single crowns on them (Group A), Figure 1-2 and twenty with titanium implants (Starumann, Switzerland), titanium abutments and porcelain -fused to metal single crowns (Group B), Figure 4-5.
The inclusion and exclusion criterion for the subject selection in the study is illustrated in table 1.On the beginning of study patients were asked to understand study protocol and accepted subjects signed the consent form to participate in the study.

Clinical Evaluation
The subjects were asked to participate for evaluation of following clinical parameters on baseline, 3 and 6 months.

Gingival index (GI) (Mombelli)
In the order to assess the severity of peri-implant soft tissue, the gingival index was used.The peri-implant tissue was divided in four analyzed unites (disto-facial papilla, facial gingival margin, mesio-facial papilla & lingual gingival margin).A score ranging from 0 to 3 was given to each surface using the periodontal probe.Score of the all unites were summed and divided by four yielded the individual implant score.Totaling all the scores per implant and dividing by implants number was used for calculation of GI per person.

Plaque index (PI) (Mombelli)
Plaque was assessed on the four peri-implant surfaces (mesial, distal, buccal and lingual) with score between 0to3.Plaque score for each implant was obtained by totaling the score for each implant and individual score was calculated.Graph 2: Plaque index -Differences between control and test subgroups in zirconium dioxide implants group.

Graph. 3:
Volpe-Manhold calculus index -differences between control and test subgroups in zirconium dioxide implants group.

Volpe-Manhold calculus index (VMI)
To obtain the VMI score, the three tooth planes (mesial, distal and gingival) on lingual surface were exterminated.The periodontal probe was used to measure supragingival calculus on the implant shoulders.The calculus was measured in increment of 0.5mm from 0 to 5mm.Score of the all three planes were summed and all implants scores were summed for subject's total VMI score.The each of forty patients were consider as the statistic unit, that presents statically minimum value for pilot study.

II Randomization
The randomization was carried out using a lot.The control or test group was randomized using sealed envelopes.Each group (A & B) was divided in to the two subgroups (control & test).

Control group
Patients from control group were advised to brush twice daily 5 minutes;

Test group
Patients from test group were advised to brush twice daily 5 minutes followed by using the calculus dissolution based oral rinse Periogen, USA, (One spoonful of Periogen was dissolved in 100ml of warm water and was directed to rinse with solution for at least one minute in three 20 seconds interval).

III Statistical Evaluation
All data were first analyzed by descriptive methods (QQ plots, box plots) (SPSS 18.0; SPSS, Austin, TX, USA).The patients were chosen as the unit for statistical analysis.The Wilcoxon signed rank test was used as well as Pearson's coefficient of correlation.The level of significance chosen in all statistical tests was at P < 0.05.

RESULTS
40 adult patients (28 females and 12 male) with mean ages 50.37 (SD ± 7.94) were involved in the study.All analyzed implants were tissue-level implants.In group A, 22 two-pieces zirconium dioxide implants (Axis Biodental.Les Bios, Switzerland) with 10 mm length and diameter 4mm were used for single tooth replacement in premolar and molar area of lower jaw.Results of clinical parameters form Group A (zirconium-dioxide dental implant) are presented in Table 1 For all clinical parameters statistical significant differences has been noted between test and control group in the assessment point of 6 months (P = 0.02) as illustrated in Figure 5 and Graph 1-3.In group B, 20 titanium SLActive (Straumann, Switzerland) implants length 8mm and 4.1, diameter were used.Results of clinical parameters form Group B (Titanium dental implant) are presented in Table 2.For all clinical parameters statistical significant differences has been noted between test and control group in the check point of 6 months (P = 0.009) as illustrated in Figure 6, Graph 4-6.

DISCUSSION
Similar study evaluated the periodontal parameters with zirconium vs titanium abutments.Less bleeding on probing and less plaque accumulation has been noted around zirconium abutment. 15Kohal et al, compared clinical and radio-graphical outcome of one-piece zirconium implants and natural teeth with fixed dental prosthesis.The modified bleeding index (mBI) and modified plaque index (mPI) were significantly lower at implants than at teeth after one year follow up period. 16esults of present study is showing statistically significant better periimplant condition around soft-tissue zirconium dioxide vs titanium implants in group treated with calculus dissolution based oral rinse Periogen (Periogen Company-USA).During six months follow-up period no side effects were recorded among any group using Periogen mouthrinse.Supplementing toothbrushing by Periogen mouthrinse will lead to success of peri-implant tissue around zirconium and titanium dental implants with significant amount of plaque and calculus reduction.

CONCLUSION
We conclude that calculus dissolution based Periogen® mouthrinse provided clinically significant reduction in calculus formation in subjects with zirconium dioxide and titanium dental implants when used twice daily for 6 months as an adjunct to toothbrushing.

Figure 6 :Graph 1 :
Figure 5: Group A -check point at 6 months.Figure 6: Group B -check point at 6 months.