Retrospective Study Regarding Orthodontic Retention Complications in Clinical Practice

At the end of any orthodontic treatment, retention is a necessary phase. Unfortunately, the current retention devices and the lack of proper oral hygiene on the part of patients lead to the accumulation of dental plaque, periodontal inflammation, and gingival retraction. Our retrospective study included 116 adult patients wearing various types of orthodontic retainers. To quantitatively determine the accumulation of dental plaque, we used the Quigley–Hein plaque index modified by Turesky and the Navy plaque index modified by Rustogi. Another studied parameter was related to the gingival recession associated with retention devices. We had investigated the correctness of patients’ dental hygiene, their preferences for auxiliary means of oral hygiene, the consistency with which they wear the mobile retainers, and respect the orthodontist’s instructions; we also investigated the inconveniences and the accidents that may occur during the retention period. Statistical analysis showed that plaque accumulation is significantly lower in the case of mobile retainer than fixed retainer wearers; the exception was the Hawley plate, where the interdental plaque was more than in all the other studied retainers. Periodontal recessions were more frequent in the case of fixed retainer wearing. Flossing was the most commonly used auxiliary mean for oral hygiene. The compliance of women in wearing vacuum-formed retainers was better than that of men. Patients with a class III history had more plaque accumulation, and class II/1 had the most problems related to detachment/damage of fixed retainers. Mobile retainers proved better results for oral hygiene, but fixed retainers cannot be waved.

Shear Bond Strength of Four Types of Orthodontic Retainers after Thermocycling and Cyclic Loading

Objectives. This study assessed the shear bond strength (SBS) of four types of orthodontic retainers after thermocycling and cyclic loading. Materials and Methods. This in vitro, experimental study evaluated 120 extracted mandibular central and lateral incisors. The teeth were mounted in acrylic resin blocks in sets of three, such that the interdental contacts and positioning of the teeth resembled the dental arch. The acrylic blocks were divided into four groups (n = 10) for the use of 0.016 × 0.022-inch Bond-A-Braid® wire, 0.0195-inch twisted wire, 0.0175-inch coaxial wire, and 0.038 × 0.016-inch Ortho-Flex Tech® wire, as retainers. The retainers were bonded to the lingual surface of the teeth with Transbond XT adhesive in all groups, and the specimens underwent thermocycling and cyclic loading (125,000 load cycles applied to the incisal edge of the incisor tooth in the middle, simulating 6 months of clinical service). Any fracture in the process of aging was recorded. The teeth were then subjected to vertical loads applied along their occlusoapical axis in a universal testing machine to determine the SBS in Newtons. The adhesive remnant index (ARI) scores were also determined. Data were analyzed using ANOVA, the Monte Carlo chi-square test, and the Kruskal–Wallis test. Results. Thermocycling and cyclic loading did not cause degradation or fracture of the retainers. The SBS and ARI scores of the four groups were not significantly different ( P > 0.05 ). Conclusion. The SBS of retainers with flat rectangular-shaped cross-section was similar to that of retainers with a round cross-section; thus, they have no superiority over each other in this respect.

Evaluation of antimicrobial properties of nano-silver particles used in orthodontics fixed retainer composites: an experimental in-vitro study

Background. The present study evaluated the antimicrobial efficacy of composite resins containing nano-silver (NAg) particles used in fixed orthodontic retainers. Methods. Nano-composite resin samples with 1%, 2%, and 5% concentrations of NAg were prepared. The antimicrobial effectiveness of NAg was assessed against Streptococcus mutans, Streptococcus sanguis, and Lactobacillus acidophilus by the biofilm inhibition test (three-day-old biofilms), eluted components test (on days 3, 15, and 30), and disk-diffusion agar test after 48 hours. Measures of central tendency and index of dispersion were used to determine colony-forming units. Kruskal-Wallis test and Mann-Whitney U test were also used. Results. The biofilm inhibition test showed a significant decrease in the colonies of S. mutans (87.64%, 96.47%, and 99.76% decrease), S. sanguis (98.13%, 99.47%, and 99.93% decrease), and L. acidophilus (81.59%, 90.90%, and 99.61% decrease) at 1%, 2%, and 5% concentrations of Nag, respectively, compared to the control groups. The colony-forming unit (CFU)/mL of tested microorganisms continuously decreased with increased NAg concentration. In the eluted component test, no significant differences were noted in the 3rd, 15th, and 30th days between the different concentrations of Nag-containing composite resin disks and control samples. According to the disk-diffusion agar test, there was no growth inhibition zone for the composite resin disks containing 1% and 2% concentrations of Nag. However, the growth inhibition zone was seen with a 5% concentration, with a diameter of 9.5±0.71 mm for S. mutans, 8.5±0.71 mm for S. sanguis, and 8±1.41 for L. acidophilus. Conclusion. The incorporation of NAg into composite resins has antibacterial effects, possibly preventing dental caries around fixed orthodontic retainers.

Orthodontist and periodontist’s knowledge, attitudes and aspects of clinical practice, regarding fixed lower orthodontic retainers

ABSTRACT Objective: This study aimed to assess the knowledge, attitudes, and aspects of the clinical practice of orthodontists and periodontists, regarding lower fixed orthodontic retainers. Methods: The orthodontists (n=502) and periodontists (n=269) who participated in this cross-sectional observational study received, via e-mail, questions related to the type of lower fixed retainer, dental biofilm accumulation, oral hygiene, and potential periodontal changes. The data were subjected to chi-square and Fisher’s exact tests, at 5% significance level. Results: Both orthodontists (72.3%) and periodontists (58.7%) reported that hygienic retainers accumulate more dental biofilm (p< 0.05), and 64.1% of orthodontists and 58.7% of periodontists considered that modified retainers may lead to periodontal changes (p< 0.05). There was no significant difference between the dental specialties, regarding the type of lower fixed retainer considered the easiest for the patient to perform hygiene (p> 0.05), whereas 48.6% of professionals chose the modified type. Conclusion: The modified retainer accumulates a greater amount of dental biofilm and, in the perception of orthodontists and periodontists, it may cause periodontal changes.