A histologic comparison of effects of electrosurgical resection using different electrodes

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.

Preclinical evaluation of porcine colon resection using hollow core negative curvature fibre delivered ultrafast laser pulses

Ultrashort pulse lasers offer great promise for tissue resection with exceptional precision and minimal thermal damage. Surgery in the bowel requires high precision and minimal necrotic tissue to avoid severe complications such as perforation. The deployment of ultrashort lasers in minimally invasive or endoscopic procedures has been hindered by the lack of suitable optical fibres for high peak powers. However, recent developments of hollow core microstructured fibres provide potential for delivery of such pulses throughout the body. In this study, analysis of laser ablation via a scanning galvanometer on a porcine colon tissue model is presented. A thermally damaged region (<85 μm) and fine depth control of ablation using the pulse energies 46 and 33 μJ are demonstrated. It is further demonstrated that such pulses suitable for precision porcine colon resection can be flexibly delivered via a hollow core negative curvature fibre (HC-NCF) and again ablation depth can be controlled with a thermally damaged region <85 μm. Ablation volumes are comparable to that of early stage lesions in the inner lining of the colon. This study concludes that the combination of ultrashort pulses and flexible fibre delivery via HC-NCF present a viable route to new minimally invasive surgical procedures.

Controlling depth of electrosurgery after curettage of skin tumors-an in vitro study

BACKGROUND

Depth of tissue injury in electrosurgery depends on generator power, electrode size, speed of electrode movement on tissue, and current delivery method. We sought to evaluate the depth of tissue injury associated with different methods of electrocoagulation in an effort to make electrocoagulation more reproducible.

METHODS

A knife-shaped electrode was used to apply an electrosurgical current to the surface of a piece of bovine liver. Different electrosurgical methods were performed. Cross sections of the liver were then studied for tissue effect.

RESULTS

Fulguration provided only superficial coagulation. Contact electrocoagulation and electrodesiccation using the flat side of the electrode provided significantly deeper levels of coagulation and were associated with less smoke than fulguration. Desiccation provided the deepest tissue effect.

CONCLUSIONS

Electrofulguration can be used for superficial tissue destruction. For deeper coagulation, a relatively larger electrode can be used in contact mode. Slower movement of the electrode on tissue in contact mode is associated with desiccation and the deepest level of tissue destruction.

How Frequency of Electrosurgical Current and Electrode Size Affect the Depth of Electrocoagulation

BACKGROUND

Many factors affect the depth of electrocoagulation.

OBJECTIVE

To evaluate the effect of current frequency and electrode size on the depth of electrocoagulation.

METHODS AND MATERIALS

In this in vitro study, 4 cylindrical electrodes (2, 2.3, 3, and 4 mm) were used to apply 3 electrosurgical currents (0.4, 1.5, and 3 MHz) to bovine liver. Each electrode was placed at different points on the surface of the liver, and energy at various levels and frequencies was delivered to the tissue. Subsequently, cross-sections of the liver were analyzed.

RESULTS

Coagulation started at the periphery of the electrode-tissue contact area. With higher energy levels, coagulation spreads to involve the remainder of the contact area. Neither the frequency nor the electrode size had any effect on this coagulation pattern. The frequency of the current also did not show any relation with depth of coagulation; however, there was a direct correlation between the size of the electrode and the depth of coagulation.

CONCLUSION

Larger-tip electrodes provided deeper coagulation compared with finer-tip electrodes.

Comparing the outcomes of incisions made by colorado microdissection needle, electrosurgery tip, and surgical blade during periodontal surgery: A randomized controlled trial

Context

Electrosurgery offers many unique advantages such as hemostasis and precise tissue cutting; however, there are a number of disadvantages including thermal injury and delayed wound healing.

Aims

The aim of the present study was to compare the outcomes of incisions made by Colorado^® microdissection needle, electrosurgery tip, and surgical blade during periodontal surgery.

Settings and Design

Twenty-two individuals participated in this study. Three quadrants in each individual were randomly assigned into each of the following experimental groups: Colorado^® microdissection needle (CMD), electrosurgery tip (EC) and surgical blade (BP), in which, incisions were given with Colorado^® microdissection needle, straight electrocautery tip, and a scalpel blade, respectively.

Materials and Methods

Blood loss (BL) was measured immediately after surgery, and changes in interdental papilla dimensions were recorded at baseline, 7, 30, 120, and 180 days after surgery. Measures of periodontal disease were recorded at baseline, 120, and 180 days after surgery. Postoperative pain and wound healing were recorded at 1, 7, and 15 days after surgery.

Results

The use of CMD for periodontal surgery showed better results over EC in all parameters. CMD resulted in lesser bleeding and less postoperative pain and attained similar results to that of BP in clinical parameters of periodontal disease.

Conclusions

Colorado^® microdissection needle may be a better choice for incisions as it seems to show less tissue damage than cautery and offers tissue healing comparable to scalpel blade.

Electrosurgery: part I. Basics and principles

The term electrosurgery (also called radiofrequency surgery) refers to the passage of high-frequency alternating electrical current through the tissue in order to achieve a specific surgical effect. Although the mechanism behind electrosurgery is not completely understood, heat production and thermal tissue damage is responsible for at least the majority--if not all--of the tissue effects in electrosurgery. Adjacent to the active electrode, tissue resistance to the passage of current converts electrical energy to heat. The only variable that determines the final tissue effects of a current is the depth and the rate at which heat is produced. Electrocoagulation occurs when tissue is heated below the boiling point and undergoes thermal denaturation. An additional slow increase in temperature leads to vaporization of the water content in the coagulated tissue and tissue drying, a process called desiccation. A sudden increase in tissue temperature above the boiling point causes rapid explosive vaporization of the water content in the tissue adjacent to the electrode, which leads to tissue fragmentation and cutting.

An Immunomodulatory Protein (Ling Zhi-8) from a Ganoderma lucidum Induced Acceleration of Wound Healing in Rat Liver Tissues after Monopolar Electrosurgery

The purpose of this study was to investigate the effect of an immunomodulatory protein (Ling Zhi-8, LZ-8) on wound healing in rat liver tissues after monopolar electrosurgery. Animals were sacrificed for evaluations at 0, 3, 7, and 28 days postoperatively. It was found that the wound with the LZ-8 treatment significantly increases wound healing. Western blot analysis clearly indicated that the expression of NF-κB was decreased at 3, 7, and 28 days when liver tissues were treated with LZ-8. Moreover, caspase-3 activity of the liver tissue also significantly decreases at 7 and 28 days, respectively. DAPI staining and TUNEL assays revealed that only a minimal dispersion of NF-κB was found on the liver tissue treated with LZ-8 at day 7 as compared with day 3 and tissues without LZ-8 treatment. Similarly, apoptosis was decreased on liver tissues treated with LZ-8 at 7 days when compared to the control (monopolar electrosurgery) tissues. Therefore, the analytical results demonstrated that LZ-8 induced acceleration of wound healing in rat liver tissues after monopolar electrosurgery.

Gingival displacement for impression making in fixed prosthodontics: contemporary principles, materials, and techniques

The clinical success and longevity of indirect restorations depend on the careful and accurate completion of several procedures. One of the challenging procedures is management of the gingival tissues and gingival esthetics. The goal for management of gingival tissues and gingival esthetics is to maintain the normal appearance of healthy gingival. Achieving this goal requires optimal health before treatment and minimal trauma during treatment. The best way of optimizing health and minimizing trauma is to avoid contacting the gingiva with restorative materials.

Confounding factors and diagnostic accuracy of imprint cytology

BACKGROUND

Eradication of malignant tumors at the primary site with oncological safe margin is a critical requirement for obtaining better survival rate and less recurrence. Touch imprint cytology (TIC) has proven itself as a quick, simple, inexpensive, highly accurate and reliable intraoperative technique to assess surgical margins in squamous cell carcinomas of the oral cavity. However, it is still unclear how the mode of excision, i.e. by scalpel (SC) and electrocautery (EC), or the method of staining, i.e. Papanicolaou (PAP) and cytohaem, affect the diagnostic accuracy of TIC.

OBJECTIVE

To study the influence of confounding factors like mode of excision (EC/SC) and staining (PAP/cytohaem) on the diagnostic accuracy of intraoperative TIC technique for assessing surgical margins in oral squamous cell carcinoma in comparison to paraffin-embedded HE-stained sections.

MATERIALS AND METHODS

Thirty patients underwent surgical treatment for primary oral squamous cell carcinoma. Three hundred and forty-eight touch imprint slides were prepared from 174 margins of 30 resected tumor specimens. Two adjacent tissues from the margin to be evaluated were imprinted to observe differences between surfaces excised by EC and SC. The set of imprint from each margin tissue was stained with PAP and cytohaem. The TIC results of 180 EC-excised margins and 168 SC-excised margins were compared. Results of 174 imprints stained with RAPID-PAP were compared to their counterpart comprising of 174 cytohaem-stained imprints. The slides were diagnosed as positive, negative or suspicious for tumor. Finally, TIC results were checked against their respective histopathological sections.

RESULTS

No statistically significant difference was found between the results of imprints from EC/SC-excised margins (Z = 0.44, p = 0.70) or the imprints stained with PAP/cytohaem (Z = 0.44, p = 0.70).

CONCLUSION

Confounding factors like mode of excision and staining procedure do not significantly influence the results of imprint cytology.

Electrosurgery--a biological approach

Electrosurgery has been used in dentistry for more than 50 years. Both opponents and advocates of electrosurgery have presented a variety of clinical studies in favour of their respective opinions, which are discussed in the following review. In some studies, wounds created by electrosurgical techniques were observed through the healing stages, in comparison to those following incision by a surgical blade, with no significant difference being discovered. Other studies reported that the histologic response of oral connective tissue to electrosurgery was adverse in some animal and human models. However, neither of these groups used methods that allowed documentation or control of operating variables. A critical evaluation of controlled clinical studies shows that adverse responses of (connective) tissue, epithelium, bone, cementum, and periodontal attachment are related to an excessive lateral heat production during the procedure. With electrosurgery, the clinician can control the inherent variables. Waveform, frequency, size of the electrode, time of contact and cooling periods are some of those considered to be of importance in the studies. On the basis of the research reports, clinical guidelines have been developed to give practical advice to the clinician using electrosurgery. Providing that these safeguards are adhered to, scientific evidence supports the biological compatibility of electrosurgery for intraoral surgical procedures.

Histologic evaluation of gingival response to an electrosurgical blade

Lateral heat production during the use of electrosurgical procedures in the oral cavity causes denaturation of the connective tissue adjacent to the incision line. This study evaluated the denatured zone following electrosurgery incision in dog gingiva with a traditional tungston wire electrode and a no. 15 surgical blade adapted for electrosurgery use. The effects of using a passive electrode during surgical procedures and using an "autosensor" circuit to control power adjustment were also evaluated. It was found that a surgical blade adapted for electrosurgery produces a zone of denatured tissue that is not statistically different from that produced with a wire electrode. Moreover, no differences were noted between incisions produced with manual power adjustment and those with power controlled by the "autosensor" circuit. A significantly wider zone of denatured tissue was produced when incisions were made without a passive electrode in place.

Biometric comparison of bur and electrosurgical retraction methods

A biometric comparison of two retraction methods was made on 20 adult patients who received complete crowns. Free gingival tissue height was recorded after 4, 8, and 12 weeks. The conclusions were (1) the electrosurgical method showed more tissue loss at each time interval than the bur method, (2) electrosurgical retraction showed more subject variability than the bur method, (3) clinically, the tissue appearance of both groups was indiscernable at the time intervals tested, and (4) the electrosurgical method provided for a greater bulk of impression material at the margin than the bur method.

A comparison of healing and pain following excision of inflammatory papillary hyperplasia with electrosurgery and blade-loop knives in human patients

Twenty human patients participated in a study designed to compare electrosurgery with blade-loop knives for the excision of inflammatory papillary hyperplasia in a split-mouth study. Questionnaires were used to assess pain and patient preference during a 2-week postoperative period, and photographs were made to chronicle the healing process. Healing occurred at approximately the same rate following each procedure. The majority of subjects did not perceive a difference in discomfort with either technique on the day of surgery or at any time during follow-up. Of those who did have a preference, a significant majority favored electrosurgery on the day of treatment. This preference became statistically insignificant on the second postoperative day and beyond.

Electrosurgery and wound healing: a review of the literature

This literature review and discussion has presented evidence that some additional research needs to be done in this area. Particular attention should be paid to control certain variables: kind and type of waveform, shape and size of electrode, and speed of the electrode through the tissue so that meaningful results may be given to the dental profession. The evaluation of the literature seems to show that when the variables are controlled, untoward results of wound healing after electrosurgery seem unwarranted.

Lateral heat production secondary to electrosurgical incisions

Adverse healing responses, including necrosis of soft tissue and sequestration of alveolar bone, have been reported following the use of electrosurgery for intraoral incisions. These responses are usually attributed to excessive heat accumulation during the surgical procedure. The purpose of this investigation was to measure temperature changes in subadjacent connective tissue during intraoral electrosurgical incisions in palatal mucosa of miniature swine. Results indicate that single electrosurgical incisions should be accomplished at a speed of approximately 7 mm. per second and that successive incisions should be separated by a cooling interval of 8 to 10 seconds to avoid generation of heat sufficient to initiate an adverse healing response.

Epithelial and connective tissue healing following electrosurgical incisions in human gingiva

Electrosurgery is used for intraoral incisions by many clinicians. Much controversy surrounds the effect of lateral heat produced during the electrosurgical incision upon the healing of adjacent connective tissue. Ten electrosurgical incisions were made in the gingiva in each of five adult male volunteers. The duration of incision and actual energy production for each incision were calculated. Excisional biopsies of the incisions were obtained at 0-504 hours. At the light microscopic level, epithelium, totally degenerated immediately following the electrosurgery incision, showed extensive activity at 24-48 hours and had covered all wounds by 72 hours. Early hour specimens showed a homogenous connective tissue region, adjacent to the wound site, devoid of cells and fibers. This zone of denatured connective tissue gradually diminished until it was no longer present at 396 hours.

Healing of electrosurgical incisions in gingiva: early histologic observations in adult men

The healing of electrosurgical incisions in the gingivae of adult men was investigated at 6-hour intervals. Clinical observation indicated that incisions healed progressively until 72 hours, when they were barely discernible. Clinical evidence of inflammation associated with the wounds was negligible. At a light microscopic level, initial reaction to electrosurgical incisions included disruption of the surface epithelium and denaturation of the connective tissue lateral to the incision. The zone of denatured connective tissue remained for the entire 72-hour period of this study. Young fibroblasts and vascular proliferation were evident in the connective tissue at 30 hours. Epithelium exhibited complete bridging of the wound surface in some specimens as early as 30 hours after incision. All specimens had an intact epithelial surface at 48 hours. Mild-to-moderate accumulations of inflammatory cells, consisting primarily of lymphocytes, surrounded the wound edges. Acute inflammation with polymorphonuclear leukocytic infiltration was not observed, except for moderate accumulation at 6 to 12 hours. Subepithelial hematoma formation within the connective tissue was evident in four of the size specimens at 72 hours.

A method to measure operating variables in electrosurgery

Variables affecting tissue response to electrosurgical wounding have been identified and discussed. An electronic measuring device was designed and built to record actual power generated at the active electrode during surgical use of an electrosurgery instrument. In addition, this electronic device measures the amount of time the active electrode is in contact with tissue. Coupled with an electrosurgery unit producing a documented waveform and an electrosurgery electrode having a controlled-depth gauge, variables affecting tissue response to electrosurgery wounding may be measured.