It is difficult to categorize the toothbrushes as sonic, because many types of toothbrushes are commercially available nowadays with various bristle shapes. Therefore, it is necessary to evaluate individual products to study their efficiency.

The aim of this study was to evaluate the effects of Sonicare^® FlexCare Platinum (a sonic toothbrush from Philips) on plaque and intra-pocket bacterial removal and clinical parameters in comparison with those of a manual toothbrush.

A total of 20 patients with periodontitis were equally divided into the sonic toothbrush group and manual toothbrush group. The clinical parameters and intra-pocket bacterial and plaque accumulation were examined prior to providing the toothbrushing instructions and at 2 and 4 weeks after the study was begun. The intra-pocket bacterial accumulation was measured at 4 weeks after the study was begun.

No significant difference in the amount of plaque accumulation was observed between the two groups. The clinical parameters improved in both the groups, with significant differences observed between the initial and final measurements. A significantly greater degree of decrease of the BOP and PD was observed in the sonic toothbrush group as compared to the manual toothbrush group at 2 weeks after the study was begun. At 4 weeks after the study was begun, significant decrease in the intra-pocket bacterial accumulation was observed in both the groups, although there was no significant difference in this parameter between the two groups.

Although no significant difference was observed in the amount of plaque accumulation, early improvement of the BOP and PD was observed in the sonic toothbrush group.

It is speculated that the early improvement of the clinical parameters in the sonic toothbrush group as compared to the manual toothbrush group was caused by the sonic vibrations exerting a massage effect on the gingiva.

Hereditary gingival fibromatosis (HGF) is a rare genetic disorder characterized by fibrous proliferation of the gingiva. Gingival overgrowth in cases of HGF usually begins in early childhood. In regard to the pathogenesis, while the genetic background is known to be the predominant factor in the development of HGF, dental plaque is also known to induce the onset and recurrence of gingival overgrowth after surgical intervention. Surgical interventions, such as conventional gingivectomy, after initial periodontal therapy is the most commonly used treatment strategy for HGF.

It is essential to maintain good oral hygiene and perform resection of the excess gingival tissue in cases with recurrent HGF after surgical treatment. According to reports published in the literature, patients with HGF have a tendency towards malocclusion. It is conceivable that malocclusion in HGF patients would result not only in functional and aesthetic problems, but also affect the rate of progression and risk of recurrence of gingival hyperplasia as a plaque retention factor along with the growth of the gingiva at the site of recrudescence.

We present the case of an 18-year-old female patient who presented with severe gingival overgrowth and was diagnosed as having HGF. Her three-generation Japanese family had at least four individuals with gingival hyperplasia. Comprehensive dental treatment, including initial periodontal therapy, periodontal surgical intervention and orthodontic treatment yielded a favorable response. Therefore, through our treatment experience over the last 10 years, we have observed the efficacy of periodontal surgery in cases of severe HGF and verified the effectiveness of managing the plaque retention factor by comprehensive dental treatment.

A 51-year-old woman with severe generalized chronic periodontitis was treated by an interdisciplinary approach, including initial preparation, periodontal surgery, oral rehabilitation and supportive periodontal therapy (SPT), for 19 years. The experience revealed that control of inflammation and occlusion during the SPT phase were necessary to maintain the mastication function over the long-term. Furthermore, it was also important to carry out affirmative treatment immediately after a recurrence or worsening of symptoms.

Rodent models, such as mouse and rat models, are often used in investigations of the oral cavity, including in the field of periodontology. When various treatments are carried out in the oral cavity, keeping the animals' mouths in an open state in addition to securing a field of view is extremely important to ensure consistency of the experimental procedures. However, few mouth gags for mice have been developed so far. We developed a standardized mouth gag conforming to various sizes of the oral cavity for mice of different ages, as well as similar gags for rats.

The gag is composed of a rectangular incisor-opening frame constructed from a stainless steel wire with a diameter of 1.5 mm, right and left buccal-towing hooks disposed in opposite directions to each other inside the frame, and an adjustment dial for the amount of opening. BALB/c mice (n = 4) aged 4 weeks (weight; 18.3±1.1 g), 6 weeks (21.5±0.9 g) and 10 weeks (30.4±2.1 g) were used to evaluate the suitability of the gag for the oral cavities of mice.

By adjusting the dial to alter the amount of mouth opening, both maintenance of the open state and intraoral observation could be accomplished favorably in all the mice of different ages and weights. Tweezers as a control device corresponding to the mouth gag were utilized. The amount of mouth opening by the gag was measured. The distance between the upper and lower incisors was 10.9-12.0 mm and the width between the left and right corners of the mouth was 8.6-9.2 mm.

As tests for application of the gag in oral experiments on mice, periodontal experiments involving a drug injection and silk ligature placement around the maxillary first molar were performed. Furthermore, usability of some of the oral experimental instruments was examined as using the gag. The gag for the mice allowed insertion of various instruments into the oral cavity in these experiments. The gag can be autoclaved and sterilized by dry heat.

The gag has been already registered as a utility model (publication number 2014-004789).

An overview of specialty training and accreditation system in periodontology in Hong Kong is presented, through the experience of serving as an external examiner of the College of Dental Surgeons of Hong Kong Periodontology exit examination 2016.