Preimpression troughing with the diode laser: A preliminary study

Intraoral Applications of Lasers in the Prosthetic Rehabilitation with Fixed Partial Dentures-A Narrative Review

Laser, an acronym for Light Amplification by Stimulated Emission of Radiation, is a powerful tool with diverse applications in modern dentistry. It emits monochromatic, coherent light resulting from photon-induced chain reactions. Available dental lasers include diode, argon, Er,Cr:YSGG, Er:YAG, Nd:YAG, and CO2. The unique property of these lasers, allowing them to be effectively used on both soft and hard tissues based on the operational parameters, positions them as particularly suited for a wide range of dental procedures. Compared to traditional methods, lasers offer advantages such as improved hemostasis and quicker wound healing. Such benefits stress the shift towards laser technology in dental treatment. In the realm of dental prosthodontics, which focuses on esthetics, functionality, and the physiological aspects of dental prostheses, lasers provide promising outcomes. Among the prosthetic options, fixed partial dentures stand out for their ability to mimic natural teeth, offering both esthetic and functional features, leading to satisfactory long-term outcomes if managed properly. This review paper delves into the specific application of laser technology in the context of prosthetic rehabilitation involving fixed partial dentures. By investigating intraoral laser procedures, it contributes to understanding laser's role in improving patients' satisfaction and clinical efficiency in this field.

Comparative evaluation of the effect of impregnated retraction cord versus laser on gingival attachment level and pain perception following retraction for subgingival margins - A prospective, split-mouth, controlled, clinical study

AIM

To evaluate and compare the effect of impregnated retraction cord vs Laser on gingival attachment level and pain perception following retraction for subgingival margins.

SETTINGS AND DESIGN

Many methods for achieving and measuring the amount of gingival retraction in fixed prosthodontic work have been advocated. Though the gingival attachment level is crucial in Periodontology, the literature available regarding the effect of these retraction methods on the same is scarce. Hence, this clinical study was designed to compare the pain perception and amount of gingival recession when impregnated cord and laser were used for retraction.

MATERIALS AND METHODS

In 40 subjects (age range of 20 to 40 years) with single missing maxillary incisor, the abutments were prepared with subgingival margins, to receive a full coverage metal-ceramic fixed dental prosthesis. The gingiva was retracted on one of the abutments with impregnated retraction cord and on the other with diode laser. Gingival attachment levels were compared at six sites per abutment using superimposition of digital scans, preoperative and four weeks after cementation of final prosthesis.

STATISTICAL ANALYSIS USED

Statistical analysis of the data for gingival recession was done using t-test. Pain perception was analysed with Chi-square test. Pain perception by patients following retraction was compared with VAS scale.

RESULTS

The average values of gingival recession on buccal side were 0.61 mm and 0.38 mm and on the palatal side were 0.58 mm and 0.35 mm for impregnated retraction cord and laser respectively. The P values of <0.01 indicated a highly significant difference between the two groups. Intragroup comparison did not show significant differences between various sites. Pain and discomfort produced by cord method was moderate in comparison with mild/no pain with diode laser and the difference was highly significant.Conclusion: Retraction cord produced more gingival recession than the diode laser, which was statistically highly significant on both buccal and palatal aspects of the teeth. Patients experience with diode laser technique was less painful in comparison with retraction cord method.

Effectiveness of laser-assisted gingival troughing and conventional gingival displacement methods in fixed prosthodontics: A systematic review

STATEMENT OF PROBLEM

High-level evidence that gingival troughing using dental lasers has better outcomes for the management of gingival tissue surrounding prepared teeth compared with conventional gingival displacement methods is lacking.

PURPOSE

The purpose of this systematic review was to review in vivo studies on gingival troughing using dental lasers to compare achieved gingival displacement, influence on periodontal health, and other relevant clinical parameters with different existing gingival displacement methods.

MATERIAL AND METHODS

The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and identified studies through January 2022. An electronic search was conducted on the digital databases PubMed/MEDLINE, Web of Science, Scopus, and Embase to identify relevant studies with no limit on publication year.

RESULTS

Nine studies were included in this systematic review. Five studies measured achieved horizontal gingival displacement, where lasers show the highest pooled mean of 0.53 mm, among all other displacement methods. Six of the 9 included studies measured periodontal health parameters, with a follow-up time up to 1 year, and other clinically relevant parameters: hemorrhagic control, time needed, ease of use, tooth mobility, pain, and tooth hypersensitivity.

CONCLUSIONS

Gingival displacement and bleeding control appeared to be better achieved using lasers. The time needed to achieve gingival displacement was shortest and easiest with lasers. Lasers resulted in either less or comparable gingival recession, lower impact on tooth hypersensitivity, and less pain during the procedure than other methods.

A Comparative Analysis of Post-Retraction Changes in Gingival Height after Conventional and Surgical Gingival Displacement: Rotary Curettage, Diode and Er:YAG Laser Troughing

The aim of the current article is to analyze and compare post-retraction gingival height changes resulting from six different types of gingival-displacement methods, encompassing both conventional and surgical approaches. The study involved a comparative analysis of 263 teeth (consisting of 128 front teeth, 69 premolars, and 66 molars) from 23 patients. For the investigation, three classic retraction methods were utilized, namely the single-cord technique, retraction paste Expasyl, and retraction paste Astringent. Additionally, three surgical techniques were employed, which included ceramic bur rotary curettage, Er:YAG laser troughing, and diode laser troughing. A randomized split-mouth design was implemented, and a significance level of 0.05 was used for the study. The recovery of the free gingival margin height was assessed on gypsum models that were scanned using an intraoral scanner during the first and second week after the retraction procedure. The results revealed that all retraction methods, except for ceramic bur rotary curettage, led to clinically insignificant levels of gingival recession. The article provides insights into the effectiveness and safety of various gingival-displacement techniques, highlighting that most methods tested in the study resulted in minimal or negligible gingival recession post-retraction.

Contemporary concepts on periodontal complications from prosthetic and restorative therapies

The clinical outcome of every prosthetic and restorative procedure depends on the maintenance of a healthy periodontium. It is, therefore, important that the prosthodontist and restorative dentist cause no harm or permanent damage to the underlying hard and soft tissues when performing clinical procedures necessary to carry out the planned treatment. Several factors involved in these procedures have been described to have an impact on gingival health. For the present article, a selection of four of these factors are presented with the goal of evaluating the current trends and their influence on periodontal structures: (1) tooth preparation configuration and apical extension, (2) gingival tissue sulcular expansion/retraction, (3) prosthetic contours, and (4) prosthesis marginal adaptation and the consequences of excess cement remnants. Based on the available scientific evidence and clinical experience, recommendations for the practitioner are given.

Does luminosity and smear layer influence 810 nm laser energy transmission through human dentine?

PURPOSE

The aim of this study was to evaluate the influence of luminosity values and smear layer on transmission characteristics of 810 nm near infrared laser energy through dentine, using extracted human teeth.

METHODS

A total of 200 teeth treated with endodontic medicaments to cause discolouration (Ledermix, Doxypaste or Odontopaste) were selected, to give a range of values for tooth shade (luminosity values). Sectioned teeth had smear layer created or removed. Near-infrared laser energy transmission was assessed using an 810 nm diode laser (90 mW, CW mode) with the tip placed at 2 mm and 4 mm from the external root surface, and a laser power metre.

RESULTS

Both tooth shade and smear layer had independent attenuating effects. Transmission of laser energy was significantly lower in teeth with darker shades. There was a strong positive correlation between relative luminosity (lighter tooth colour) and transmitted laser power (r = 0.9271 for the Spearman rank correlation, P = 0.0022). When a smear layer was present, this significantly reduced the transmission of laser energy through the sample, compared to when no smear layer was present.

CONCLUSION

The results of this laboratory study highlight the attenuating influence of a darker tooth shade and the presence of smear layer on the transmission of 810 nm light when directed onto the surface of human dentine. Such effects may be relevant to photo biomodulation, Photodynamic Therapy and other dental laser treatments.

Evaluation of gingival displacement methods in terms of periodontal health at crown restorations produced by digital scan: 1-year clinical follow-up

The purpose of this clinical study was to compare the effects of the gingival displacement techniques of retraction cord, cordless paste system, and Er,Cr:YSGG laser troughing on the periodontal tissues around the crown restoration produced using a digital scan. This was analyzed by recording the probing depth (PD), plaque index, gingival index (GI), mobility, sensitivity, and bleeding on probing (BOP) index. This study included 60 mandibular 1^st molars from 52 participants (20 males and 32 females) requiring crown restoration. The margin lines of the crown preparations were placed 1 mm subgingivally. Based on the gingival displacement technique used, the patients were divided into three groups: retraction cord, cordless paste system, and Er,Cr:YSGG laser troughing. A digital scan of the prepared tooth was performed. Follow-up appointments were scheduled at five different times: 1^st day, 1^st month, 3^rd month, 6^th month, and 1^st year. Six periodontal indices were used to assess the periodontal health. The chi-square test was used to compare categorical variables depending on the groups. There was a significant difference in the PD, GI, and BOP index scores among the three techniques during the 1-year clinical monitoring (p < 0.001). The PD in the three zones of the buccal surface showed a significant increase with time in the retraction cord and cordless paste system groups (p < 0.001). The highest GI scores were observed in the retraction cord group on the 1^st day. The Er,Cr:YSGG laser troughing procedure produced lower PD, GI, and BOP index scores as compared to the retraction cord and cordless paste system procedures in the 1-year period.

The Integration of a Dual-Wavelength Super Pulsed Diode Laser for Consistent Tissue Ablation in the Esthetic Zone: A Case Series

Introduction

A diode laser is one of the universally compact accepted laser systems used fundamentally for soft tissue applications. Most diode laser devices have a single wavelength of either 810 nm for superior coagulation or 980 nm for tissue ablation. In these case series, the use of dual wavelengths (810 nm and 980 nm) in combination with super pulsing has provided a cleaner cut (no charring) with faster healing that eases the placement of the final restoration in the esthetic zone. Case Description. The present case series describe four cases in the esthetic zone that achieved hemostasis ablation without collateral damage to enhance gingival balance of definitive restoration. The gingivoplasty and gingivectomy modes are used to achieve efficient tissue ablation. Although there is no specific mode indicated in the FDA laser requirement for gingival depigmentation, the procedure could be safely performed with the dual-wavelength diode laser.

Result

All four patients revealed a good esthetic outcome and reported no pain postoperatively. Healing was uneventful, and definitive restoration was delivered within two to four weeks postoperatively.

Conclusion

Within the limitation of these case series, the dual-wavelength super pulsed diode laser has the capacity to deliver peak powers resulting in efficient cutting and less tissue charring and also as an alternative tool for removal of gingival pigmentation. Prospective clinical research with larger sample size is needed for conclusive results.

A multicenter randomized, controlled clinical trial comparing the use of displacement cords, an aluminum chloride paste, and a combination of paste and cords for tissue displacement

STATEMENT OF PROBLEM

Gingival recession after soft tissue displacement for impression making in fixed prosthodontics may pose a problem for treatment success in the esthetic areas of the mouth. Knowledge about the soft tissue reaction of common gingival displacement methods is limited.

PURPOSE

The purpose of this clinical randomized controlled trial (RCT) was to evaluate changes in the marginal soft tissue height with 3 different gingival tissue displacement techniques for definitive impression making of natural teeth.

MATERIAL AND METHODS

A total of 67 individuals were randomized to 3 groups. In test group 1 (P; n=22), only aluminum chloride paste was used to displace the gingiva. In test group 2 (CP; n=23), a cord was inserted, and aluminum chloride paste was also used. In the control group (C; n=22), 2 cords were used to displace the gingiva (double-cord technique). Clinical measurements of the gingival position were made before treatment began and at 30 ±10 days after prosthesis delivery. Study casts were fabricated at different stages of the treatment, standardized photographs were made, and changes in the buccal gingival position were measured using graphics editing software. In addition, the participants' perception of the clinical procedure and the technicians' evaluation of the die preparation were recorded. One-way ANOVA models were applied to compare the response variables among the groups: (a) the position of the gingival margin (millimeters), (b) mean probing pocket depth (millimeters), (c) gingival thickness (millimeters), (d) amount of keratinized tissue (millimeters), and (e) mean changes in gingival margin height (millimeters). Unpaired t tests were also used to compare the mean values between groups. For comparisons between different categories, chi-square tests were performed (α=.05 for all tests).

RESULTS

In the period between impression and delivery, a minor gain in gingival height of 0.058 mm (±0.13 SD) for P and 0.013 mm (±1.19 SD) for CP. However, a minor gingival recession of 0.049 mm (±0.13 SD) was reported for group C. The results for all groups showed that 21% of abutment teeth gained >0.1 mm in gingival height, 58% had stable gingival height (0 ±0.10 mm), 21% showed minor gingival recession (0.1 to 0.5 mm), and no abutment teeth showed moderate or severe gingival recession (>0.5 mm). The incidence of minor gingival recession was 8% in group P, 23% in group CP, and 32% in group C (P=.015). Fifteen participants (24%) experienced some discomfort after the procedure. The differences between the groups were not significant (P>.05). The laboratory technicians found the definitive die preparation significantly more challenging for group P (visual analog scale [VAS], 79) and CP (VAS, 82) than group C (mean VAS, 93; P=.003).

CONCLUSIONS

Minor or moderate gingival recession (<1 mm) is more likely to occur when conventional cords are used during impression making. However, the laboratory technicians found the die preparation significantly less challenging when the double-cord technique was used than when impressions were made using the paste displacement technique.

Impression Techniques Used for Single-Unit Crowns: Findings from the National Dental Practice-Based Research Network

PURPOSE

To: (1) determine which impression and gingival displacement techniques practitioners use for single-unit crowns on natural teeth; and (2) test whether certain dentist and practice characteristics are significantly associated with the use of these techniques.

MATERIALS AND METHODS

Dentists participating in the National Dental Practice-Based Research Network were eligible for this survey study. The study used a questionnaire developed by clinicians, statisticians, laboratory technicians, and survey experts. The questionnaire was pretested via cognitive interviewing with a regionally diverse group of practitioners. The survey included questions regarding gingival displacement and impression techniques. Survey responses were compared by dentist and practice characteristics using ANOVA.

RESULTS

The response rate was 1777 of 2132 eligible dentists (83%). Regarding gingival displacement, most clinicians reported using either a single cord (35%) or dual cord (35%) technique. About 16% of respondents preferred an injectable retraction technique. For making impressions, the most frequently used techniques and materials are: poly(vinyl siloxane), 77%; polyether, 12%; optical/digital, 9%. A dental auxiliary or assistant made the final impression 2% of the time. Regarding dual-arch impression trays, 23% of practitioners report they typically use a metal frame tray, 60% use a plastic frame, and 16% do not use a dual-arch tray. Clinicians using optical impression techniques were more likely to be private practice owners or associates.

CONCLUSIONS

This study documents current techniques for gingival displacement and making impressions for crowns. Certain dentist and practice characteristics are significantly associated with these techniques.