Evaluation of Anti Bacterial Effect of Titanium Dioxide Nanoparticles on Baseplates of Twin Block
Condition: Gingival Inflammation
MeSH terms: Gingivitis; Inflammation
Study type: Interventional

Summary: 
      Background The objective of this study was to evaluate the antibacterial effect of Titanium
      dioxide nanoparticles incorporated into the acrylic baseplates of maxillary part of twin
      block appliances in orthodontic patients during the treatment period.

      Material and methods Twenty-six patients were selected randomly and divided into two
      groups(n=13). Test group patients were used orthodontic functional appliances containing
      Titanium dioxide nanoparticles in acrylic baseplates. Control group patients were used
      orthodontic functional appliances without Titanium dioxide nanoparticles in acrylic
      baseplates. Swap samples were taken from palatal gingiva facing fitting surface of acrylic
      component of maxillary part of twin block appliance for each patient at five times intervals
      (base line sample, after one, two, four, and six months) then cultured in blood agar plates
      to calculate bacterial colony count.
    

Detailed description: 
      Design of the appliance

      For all of the chosen patients, the Twin Block, which consists of upper and lower bite
      blocks, was constructed. In this study the upper bite block was used. The upper part
      incorporates labial bow with U loop around canines and Adam clasps on the upper first molars
      for retention. Midline screw may be added to the upper part of the appliance to aid in the
      correction of the posterior cross bite if occurred during treatment.

      Appliance construction (dental laboratory step) Based on cast models of each patient, acrylic
      baseplates for orthodontic appliances were manufactured using auto-polymerizing PMMA resin,
      the monomer-to-polymer ratio recommended by the manufacturer, and standard acrylization,
      trimming, and finishing-polishing processes The acrylic material used for fabrication of the
      appliance was (Acrostone acrylic material, under exclusive liscence, England). The
      manufacturer's suggested powder-liquid volume ratio is 3:1 representing 22 g of the polymer
      and 10 mL of the liquid monomer. Powder-liquid volume ratio for construction of appliance was
      calculated . This created samples were the control group.

      Intervention Titanium dioxide nano powder was prepared at City of Scientific Research and
      Technological Applications (SRTA-City) in Egypt.

      During the appliance containing TiO2 nanoparticles construction, first of all, the calculated
      quantity of titanium dioxide nano powder was mixed manually with acrylic resin polymer for 60
      s by shaking the powders inside a small container and subsequently, the calculated quantity
      of the monomer was added to obtain a PMMA containing TiO2 NPs .This created samples were the
      test group. the powder was mixed with the liquid as recommended by the manufacturer, applied
      to a mold and ﬂasked. Then the acrylic baseplate was finished and polished.

      Clinical step:

      The patients were instructed to use the device (twin block) full-time, including while they
      slept. The patients were instructed not to use mouthwashes, antibiotics, or xylitol products
      during this time but to continue brushing their teeth as usual and eating a normal diet
      instead. Prior to sample collection, the patients were told not to brush their teeth or
      practise other oral hygiene routines for 24 hours, and they were also told not to eat or
      drink for an hour.

      Sample:

      Swap Samples were taken just before wearing the appliance (base line sample) then at the
      following time intervals of wearing appliance for each group (after one month, after
      two-months, after four-months, and after six months).

      Swap was taken from palatal gingiva facing fitting surface of acrylic baseplate of maxillary
      part of twin block appliance for each patient using sterilized cotton swap then placed in 1ml
      of broth solution in sterilized tube.

      Broth solution (thioglycolate broth) which act as transport media used to refresh bacteria if
      it present and preserve it until send to lab.

      Sample examination (laboratory step) Sample examination was done in Microbiology Diagnostics
      and Infection Control unit (MDICU), Medical Microbiology and Immunology Department, Faculty
      of Medicine, Mansoura University.

      After sample had been send to the lab, vortex was done for it using Vortex Mixer VM-300 Gemmy
      for one or two minute to release all sample from the swap in the solution(1ml). Then swap was
      discarded and broth solution was used. We used 10 microns of the solution. it was cultured in
      blood agar plate. Solution was placed on the top of the plate using swap, descended on
      vertical line in the middle part of the plate then horizontal lines passing through this
      vertical line then the plate was placed in the incubator for 24 hours to calculate the colony
      forming unit / ml for streptococcus mutans.
    

Intervention name(s): titanium dioxide nanoparticles in test group
Intervention type(s): Other
Intervention description(s): Titanium dioxide nanoparticles added to acrylic baseplate in test group
Intervention MeSH terms: Titanium dioxide
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Prevention