The authors investigated the surgical and collateral effects on soft tissue of a carbon dioxide laser emitting at 9.3 micrometers. Specifically, incision widths and depths as well as effectiveness were studied. Three different laser modes were investigated: gated continuous wave, or Cw, Superpulse and OptiPulse (Medical Optics). Incision depths correlated positively with average power; higher powers produced deeper incisions. The gated Cw mode quickly produced wide, deep incisions; Superpulse achieved narrower, deep incisions; OptiPulse caused very narrow, shallow incisions. Collateral damage to adjacent tissues was reduced by a factor of about 2 using Superpulse, and by a factor of 10 using OptiPulse. A wide range of effects is achieved in soft tissue, depending on the laser parameter combination used.

Early diagnosis is the most important determinant of oral and oropharyngeal squamous cell carcinoma (OPSCC) outcomes, yet most of these cancers are detected late, when outcomes are poor. Typically, nonspecialists such as dentists screen for oral cancer risk, and then they refer high-risk patients to specialists for biopsy-based diagnosis. Because the clinical appearance of oral mucosal lesions is not an adequate indicator of their diagnosis, status, or risk level, this initial triage process is inaccurate, with poor sensitivity and specificity. The objective of this study is to provide an overview of emerging optical imaging modalities and novel artificial intelligence-based approaches, as well as to evaluate their individual and combined utility and implications for improving oral cancer detection and outcomes. The principles of image-based approaches to detecting oral cancer are placed within the context of clinical needs and parameters. A brief overview of artificial intelligence approaches and algorithms is presented, and studies that use these 2 approaches singly and together are cited and evaluated. In recent years, a range of novel imaging modalities has been investigated for their applicability to improving oral cancer outcomes, yet none of them have found widespread adoption or significantly affected clinical practice or outcomes. Artificial intelligence approaches are beginning to have considerable impact in improving diagnostic accuracy in some fields of medicine, but to date, only limited studies apply to oral cancer. These studies demonstrate that artificial intelligence approaches combined with imaging can have considerable impact on oral cancer outcomes, with applications ranging from low-cost screening with smartphone-based probes to algorithm-guided detection of oral lesion heterogeneity and margins using optical coherence tomography. Combined imaging and artificial intelligence approaches can improve oral cancer outcomes through improved detection and diagnosis.

The purposes of this study were to evaluate the effects on cell growth and migration of fibroblasts derived from human dental pulp by lasers using three-dimensional (3-D) cell culture system, and to compare the results with those from conventional methods using a two-dimensional (2-D) cell culture system. After extirpation from twenty freshly extracted human third molars showing no clinical sign of caries, pulp tissues were cultured in Minimum Essential Medium using a conventional 2-D cell culture. The cells between 5 and 18 passages were used for this experiment, and collagen gel (1 mg/ml) was used for the 3-D cell culture system. The energy densities used were 0.52 and 1.04 J/cm2 for the gallium aluminum arsenide (GaA1As) diode laser emitting at 830 nm, and 0.1 and 1.0 J/cm2 for the argon (Ar)-dye laser emitting at 632 nm. After laser irradiation, cells were counted at 2, 4, 6, and 8 days, and observed at 3 days by stereomicroscopy. There was no significant difference in cell count between the control groups and the laser-irradiated groups (both lasers) on any day using the 2-D cell culture system (p > 0.01). However, there were significant differences in cell count between the control groups and the laser-irradiated groups (both lasers) at 8 days using the 3-D cell culture (p < 0.01). Cell migration appeared more accelerated by laser in 3-D cell culture than in the 2-D system. These results suggest that the 3-D cell culture system is useful for the evaluation of potential stimulative effects of lasers.

As the emphasis shifts from damage mitigation to disease prevention or reversal of early disease in the oral cavity, the need for sensitive and accurate detection and diagnostic tools become more important. Many novel and emergent optical diagnostic modalities for the oral cavity are becoming available to clinicians with a variety of desirable attributes including: (i) non-invasiveness, (ii) absence of ionizing radiation, (iii) patient-friendliness, (iv) real-time information (v) repeatability, and (vi) high-resolution surface and subsurface images. In this article, the principles behind optical diagnostic approaches, their feasibility and applicability for imaging soft and hard tissues, and their potential usefulness as a tool in the diagnosis of oral mucosal lesions, dental pathologies, and other dental applications will be reviewed. The clinical applications of light-based imaging technologies in the oral cavity and of their derivative devices will be discussed to provide the reader with a comprehensive understanding of emergent diagnostic modalities.

The purpose of this study was to determine whether a nanosecond-pulsed, frequency-doubled Nd:YAG laser emitting at 532 nm can be used as an alternative to mechanical methods of root canal treatment or as an adjunct to conventional endodontic preparation. Laser parameters whose thermal effects did not exceed safety thresholds for adjacent periodontal tissues were selected in a preliminary study. In 27 extracted human teeth, root canals were irradiated for 30 to 60 s at fluences of 2 to 2.2 J/cm2, and 10 Hz. Samples were observed using SEM. Laser irradiation could achieve smear layer removal after minimal manual preparation. However, results were inhomogeneous, and at higher energy densities thermal damage was observed, especially in the fully manually prepared samples. Nanosecond-pulsed irradiation at 532 nm can achieve complete smear layer removal. However, mechanisms must be developed to monitor laser effects and avoid potential damage to collateral structures.

This study evaluated the tooth-restoration interface between composite resin or glass ionomer cement and the tooth surface in teeth where caries removal and cavity preparation were performed either with the dental drill, the dental drill and laser irradiation, or laser irradiation alone. A nanosecond-pulsed Nd-YAG laser was used at energy densities of 2-8 J cm-2. After tooth restoration, microleakage tests were performed using methylene blue. Using general linear model procedures, no significant differences in microleakage were determined between 'drill' and 'drill and laser'-prepared groups (p < 0.01) in resin- and in glass-ionomer-restored teeth. These specimens showed significantly less dye penetration than the 'laser only' group (p < 0.0001). No correlation was found between fluence and microleakage using either restorative material (p = 0.8). Dye penetration was significantly greater in the composite-filled than in the glass-ionomer group (p < 0.05). Mechanisms influencing laser effects on bonding require further investigation before clinical application of lasers as an alternative to the dental drill can become viable.

Thermal and microstructural events resulting from KTP laser use during root canal preparation were investigated in 30 extracted single-rooted human teeth. In the first section of this study, thermal events occurring on the root surfaces of 18 teeth during and after exposure of the root canal were measured using thermography. A variety of parameters were used to determine settings that would be effective without causing thermal damage to the periodontal ligament. In the second section of the study, root canals of 12 teeth exposed to KTP laser irradiation at parameters derived from section 1 were evaluated using Scanning electron microscopy. KTP laser application at a power setting of 3 W, an exposure time of 2 s, and a frequency of 5 Hz, applied five times, removed smear layer and debris from the root canal surface at temperatures below the thermal injury threshold for periodontal tissue.

The effects of nanosecond pulsed Nd:YAG irradiation on crown and root dentin susceptibility to artificial de- and remineralization were investigated. Laser-induced heating and structural effects were also determined. Thirty caries-free extracted human molar teeth were used. One group of 12 teeth was bisected longitudinally, and each surface covered with acid resistant varnish, leaving 4 windows on the cut dentin surface. Using a Q-switched nanosecond pulsed Nd:YAG laser (1064 nm), one half of each tooth was irradiated at one of the following parameters: 3 mm spot size, a fluence of 1.0 J/cm2. The other half of each tooth served as (non-irradiated) control. All samples were then subjected to a 4 day, thrice daily de- and remineralization cycle. Prior to and after each demineralization, microhardness measurements were taken. After 4 days, samples were again bisected, and the other sample halves used for SEM. Microhardness in the irradiated samples did not differ significantly (p < 0.01) compared with controls; SEM results showed some laser-induced alterations on crown and root dentin surfaces. Thermometric measurements on 18 teeth at energy densities of 1.0-4.1 J/cm2 revealed intrapulpal temperature increases of approximately 2°C at a dentin thickness of 2 mm during irradiation. No consistent effect of Q-switched nanosecond pulsed Nd:YAG laser irradiation on microstructure and de- and remineralization of dentin was determined (p < 0.01). but SEM results showed some surface alterations on the irradiated samples.

Objectives

The goal of this prospective, randomized, controlled, double-blinded study was to evaluate the effects of a novel dental gel on plaque and gingival health. The dental gel was designed to (1) break up and prevent re-accumulation of microbial biofilm, and (2) inhibit metal mediated inflammation.

Materials and methods

Twenty-five subjects with moderate gingival inflammation (Löe and Silness Gingival Index ≥2) and pocket depths <4 were randomly assigned to brush twice daily for 21 days with the test or the control dental gel. On Days 0, 7, 14 and 21, plaque levels (Quigley-Hein, Turesky Modification Plaque Index), gingival inflammation (Löe and Silness Gingival Index) and gingival bleeding (modified Sulcus Bleeding Index) were determined by one blinded, investigator using a pressure sensitive probe.

Results

After 3 weeks, all 3 clinical indices were significantly improved in both groups (P<0.05) and significantly lower in the test group (P<0.05).

Conclusion

The novel dental gel formulation was provided effective plaque control and reduced gingival inflammation.

Clinical relevance

A novel dentifrice formulation may be an effective tool for plaque removal and maintaining gingival health.