Temperature variation in the pulp during Nd-YAG laser irradiation at tooth cervical protion in vitro / 实用口腔医学杂志

Objective:To observe the temperature vaxiation in the pulp chamber during Nd-YAG laser irradiation at tooth cervical portion.Methods:60 extracted permanent teeth were divided into 3 groups (anterior teeth,premolars and molars,n =20).The teeth in each group were further divided into 4 subgroups according to the laser power setting (0.4 W,0.8 W)and interval time(1 0 s,20 s)(n =5).After canal preparation the teeth were fixed and filmed using the parallel projection technique.the thickness of the buccal pulp chamber wall was measured by graphic analyzing software.The buccal cervical portion of the teeth was irradiated through 200 μm optical fiber,Temperature in the pulp was measured by K type thermo-electric couples fixed to the pulp chamber wall.Re-sults:The temperature inside the chamber increased with the higher power setting(P <0.01 ),under the same power setting,longer irradiation duration caused higher temperature rise(P <0.01 ).Greater chamber wall thickness was associated with lower temperature rise.Conclusion:The temperature rise in the pulp chamber during laser irradiation is correlated with laser power setting and the thickness of the irradiated tooth tissue.

Temperature variation at the external root surface during Nd: YAG laser irradiation in the root canal in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To assess the temperature variation of the root surface using Nd: YAG laser irradiation in the root canal with different power and to evaluate the safety of laser application on the periodontal region.</p><p><b>METHODS</b>Thirty extracted human teeth with single-roots were collected. The teeth were cross-sectioned in the cervical portion, standardizing the roots at a 12-mm length. The roots were used as specimen. The roots were radiographed in the buccal-lingual direction to measure the thickness of the proximal walls, by means of a digital radiographic system. The specimens were divided into three groups according to the laser potency (1.5, 3.0, and 4.5 W). Each group was subdivided into two subgroups according to laser frequency (15 and 30 Hz). With the Nd: YAG laser irradiation for 20 s, the temperature variation of the root surface was monitored by thermocouples located at different parts of the root external wall and recorded by digital thermometers.</p><p><b>RESULTS</b>The groups irradiated with 4.5 W presented the greatest temperature variation (above 10°C), followed by 3.0 and 1.5 W. The temperatures were statistically different (P < 0.01). The groups irradiated in the same potency, regardless of whether 15 Hz or 30 Hz was used, presented with no statistical difference (P > 0.05). The apical half of the root presented statistically higher temperature rises than the cervical half of the root (P < 0.01).</p><p><b>CONCLUSION</b>The temperature variation of the root surface was associated with laser power, irradiation time, and the thickness of dentin. Application of Nd: YAG laser in the root at 1.5 W for 20 s can safely be used in endodontic treatment.</p>

Root canal treatment of two-rooted three-canal maxillary first premolar: a case report / 华西口腔医学杂志

According to literature, the incidence of three-canal maxillary first premolar is between 0.5% and 7.5%. The two types of three-canal maxillary premolars are two-rooted and three-rooted three-canal maxillary premolars. Most case reports in Chinese literature focus on three-rooted three-canal maxillary premolars. To our knowledge, no domestic case report on two-rooted three-canal maxillary premolar has been published. In this study, we describe the root canal treatment of a two-rooted three-canal maxillary premolar.

The clinical study on the use of diode laser irradiation in the treatment of periodontal-endodontic combined lesions / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the adjunctive effect of diode laser irradiation for the treatment of periodontal-endodontic combined lesions.</p><p><b>METHODS</b>30 cases with periodontal-endodontic combined lesions were selected. All cases were randomly divided into experimental group and control group (n=15). In the control group, patients were treated with root canal therapy and conservative periodontal treatment (scaling and root planning), and patients in the experimental group were treated with root canal therapy and conservative periodontal treatment followed by diode laser irradiation. Clinical measurements including pocket probing depth (PPD), clinical attachment level (CAL), modified bleeding index (mBI), periapical index (PAI) were taken before treatment (baseline). Three and six months after the treatment, the adjunctive effects of diode laser in the treatment of periodontal-endodontic combined lesions were evaluated.</p><p><b>RESULTS</b>Three months after the treatment, the average PPD, CAL and mBI levels were reduced significantly in both groups. But the average PPD reduction in the experimental group was significantly greater (P<0.05) than in control group. However the average CAL and mBI reduction were not significantly different between two groups. Six months after the treatment, the average PPD, CAL and mBI levels were further reduced in the experiment group, but not in the control group. The average PAI levels were reduced significantly in both groups, but the PAI reduction was not significantly different between two groups.</p><p><b>CONCLUSION</b>The use of diode laser as an adjunct procedure in the treatment of periodontal-endodontic combined lesions can aid in achieving success.</p>