Dental and periodontal dimensions stability after esthetic clinical crown lengthening surgery: a 12-month clinical study.

OBJECTIVES: To evaluate the stability of periodontal tissues 3 (T3), 6 (T6), and 12 (T12) months after esthetic crown lengthening (ACL) and the possible correlations between changes in those structures. MATERIALS AND METHODS: Twenty individuals were evaluated through clinical assessment, photography, and tomography. Measurements included gingival margin (GM), clinical crown length (CCL), interdental papilla height (PH) and width (PW), gingival thickness (GT), bone thickness (BT), probing depth (PD), distance between alveolar crest and GM, distance between alveolar crest and cementoenamel junction. Nonparametric and correlation statistics were performed (p < 0.05). RESULTS: CCL at T0 was 7.42 ± 0.70 mm and increased to 9.48 ± 0.49 mm immediately after ACL, but it decreased to 8.93 ± 0.65 mm at T12. PD decreased 0.60 mm from T0 to T6, and it increased 0.39 mm from T6 to T12. BT decreased 0.20 mm, while GT increased 0.29 mm from T0 to T12. Both PW and PH showed enlargement in T12. A positive moderate correlation was found between CCL/T0 and CCL/T12, GT/T0 and AC-GM/T12, BT/T0 and GT/T12. A few negative moderate correlations were PD/T0 and CCL/T12, PD/T0 and PH/T0, PD/T0 and BT/T12. CONCLUSIONS: ACL procedure was effective. Although some rebound occurred, that was not clinically important. PD tended to reestablish its original length, partially due to a migration of GM during the healing period. Besides, a thickening of supracrestal soft tissues was observed. CLINICAL RELEVANCE: The present study centers on the factors influencing the stability of periodontal tissues after esthetic crown lengthening, underscoring the procedure's influence on esthetics and biology and the need for careful treatment planning.

Effects of the GingivalStat approach on early gingival margin remodeling following esthetic clinical crown lengthening: A case series.

OBJECTIVES: The aim of this case series is to present the potential applications of the GingivalStat approach, that is, the use of temporary gingival stabilizers, to favor early gingival margin remodeling and prevent the occurrence of gingival rebound following esthetic clinical crown lengthening. CLINICAL CONSIDERATIONS: Four patients requiring clinical crown lengthening were treated for esthetical and functional reasons. The surgical approach included: (a) gingival margin recontouring; (b) full-thickness flap elevation; (c) osteotomy (to achieve an adequate dimension between the alveolar bone crest and the CEJ) and osteoplasty (to reduce the bone thickness and improve the buccal bone anatomic profile, where indicated); (d) temporary gingival stabilizer placement using a block-out resin or a composite (the GingivalStat approach); and (e) flap repositioning, adaptation, and suture. One- to five-year follow-ups, reported in the different case scenarios, show evidence of clinically stable gingival margins around the treated teeth. CONCLUSIONS: Within the limits of this case series, it can be concluded that the GingivalStat approach appears as a further maneuver to cope with clinical crown lengthening procedures at esthetic sites. GingivalStat seems to favor gingival margin contour remodeling during the early phase of healing as well as prevent the occurrence of gingival rebound. CLINICAL SIGNIFICANCE: GingivalStat approach may guide gingival margin remodeling and prevent gingival rebound after wound healing of sites submitted to esthetic clinical crown lengthening.

Staged esthetic crown lengthening: Classification and guidelines for periodontal-restorative therapy.

OBJECTIVE: This article presents technical guidelines for perio-restorative esthetic crown lengthening, along with a discussion of the biologic rationale. A classification system is proposed to assist in treatment planning and sequencing the surgical and restorative phases. CLINICAL CONSIDERATIONS: When esthetic crown lengthening is performed as an adjunct to restorative therapy, the surgical approach must be determined by the anticipated position of the restorative margins. The removal of sufficient bone to achieve the desired clinical crown length and preserve the supracrestal gingival tissue dimensions is facilitated by the use of a surgical guide fabricated according to the design of the restorations. A staged approach allows sequencing the provisional restoration to minimize unesthetic sequelae during the healing period. Inadequate bone resection and/or alteration of the soft tissue dimensions results in delayed healing, leading to coronal gingival rebound and biologic width impingement. CONCLUSION: The identification and preservation of appropriate restorative and biologic landmarks is essential for success in pre-prosthetic esthetic crown lengthening treatment. A staged approach improves the esthetic management during the postsurgical healing and maturation period. CLINICAL SIGNIFICANCE: A restorative driven classification system for sequencing and staging adjunctive esthetic crown lengthening procedures is presented. Technical guidelines to enhance gingival margin predictability are suggested, accompanied by relevant evidence. In addition, wound healing timelines following gingival and osseous resection are provided.

Use of both the diode and Er: YAG lasers in esthetic crown lengthening with the aid of digitally guided dual technique: 3 years follow-up.

OBJECTIVE: To explore the feasibility of the usage of digital guides in combination with low- and high-power lasers for the treatment of excessive gingival display, also known as "gummy smile". CLINICAL CONSIDERATIONS: Excessive gingival display due to altered passive eruption can affect patient's perception of their own esthetics and consequently have an impact on self-confidence. Therefore, the management of this condition should offer a predictable and stable long-lasting solution. To attain these objectives, digital planning emerges as a tool in optimizing the outcomes of crown lengthening surgery for this condition by enhancing precision through the use of surgical guides. Additionally, the usage of high- and low-powered lasers can provide a safe approach because of their tissue selective removal properties. CONCLUSIONS: The technique described showed satisfactory clinical results in the short- and long-term follow-up, leading to an improvement in patients' self-esteem. This approach integrates digital and laser technologies to deliver a surgical treatment characterized by precision, efficiency, and safety. CLINICAL SIGNIFICANCE: Digital dentistry has contributed to innovative dental procedures, as personalizing surgical guides for patients, assisting and guiding incisions of the gingival margins, as well as the extension of the osteotomy, during the procedures for increasing the clinical crown. Furthermore, smile esthetics are directly related to an individual's improved emotional and social quality of life.

Treatment of excessive gingival display using conventional esthetic crown lengthening versus computer guided esthetic crown lengthening: (a randomized clinical trial).

BACKGROUND: Surgical guides have been proposed in an attempt to reach more predictable outcomes for esthetic crown lengthening. The objective of the present study was to evaluate the effectiveness of esthetic crown lengthening using 3D-printed surgical guides in the management of excessive gingival display due to altered passive eruption type 1B. MATERIALS AND METHODS: Sixteen patients diagnosed with altered passive eruption type 1B, were divided into two groups. In the control group, the procedure was carried out conventionally, and in the study group, a dual surgical guide was used. The parameters of wound healing (swelling, color, probing depth, bleeding index, and plaque index), pain scores, gingival margin stability, and operating time were assessed at 1 week, 2 weeks, 3 months, and 6 months postoperatively. RESULTS: There was no statistically significant difference in terms of wound healing, pain scores, and gingival margin stability between both groups at different time intervals (P = 1), however, there was a statistical difference between both groups in terms of operating time with the study group being significantly lower (P < 0.001). CONCLUSION: Digitally assisted esthetic crown lengthening helps shorten the operating time and reduces the possibility of human errors during the measurements. This will be useful in helping practitioners achieve better results. PRACTICAL IMPLICATIONS: The conventional method remains to be the gold standard. However, shorter operating time and lower margins for errors will help reduce costs as the chair side time is reduced as well as the possibility for a second surgery is lower. This will improve patient satisfaction as well.

A comparative study of the use of digital technology in the anterior smile experience.

OBJECTIVES: this study aims to compare the clinical outcomes of traditional and digital crown extension guides in the aesthetic restoration of anterior teeth. Additionally, the study will analyze the differences in the results of various digital crown extension guides in anterior aesthetic restorations. METHODS: Sixty-two patients who required aesthetic restoration of their anterior teeth were selected for this study. The patients had a total of 230 anterior teeth and were randomly divided into three groups: a control group of 22 cases who received diagnostic wax-up with pressure film, an experimental group 1 of 20 cases who received 3D printed digital models with pressure film, and an experimental group 2 of 20 patients who received digital dual-positioning guides. The control group had a total of 84 anterior teeth, experimental group 1 had 72 anterior teeth, and experimental group 2 had 74 anterior teeth. The study compared three methods for fabricating crown extension guides: the control group used the diagnostic wax-up plus compression film method, while experimental group 1 used compression film on 3D printed models and experimental group 2 used 3D printed digital dual-positioning crown extension guides. After the crown lengthening surgery, the control group patients wore DMG resin temporary crown material for gingival contouring, while the experimental group patients wore 3D printed resin temporary crowns for the same purpose. The patients were followed up in the outpatient clinic after wearing temporary crowns for 1 month, 3 months, and 6 months, respectively. The clinical results were evaluated in terms of marginal fit, red aesthetic index, and white aesthetic index. RESULTS: Based on the statistical analysis, the experimental group required significantly fewer follow-up visits and less time for guide design and fabrication compared to the control group. Additionally, the surgical time for the experimental group was significantly shorter than that of the control group. During the postoperative period between the 1st and 3rd month, the PES index scores for the marginal gingival level, proximal, and distal mesiodistal gingival papillae of the experimental group showed a trend of superiority over those of the control group. By the 6th month, the marginal gingival level exhibited a significant difference between the experimental and control groups. The experimental group demonstrated superior results to the control group in terms of shape, contour, and volume of the teeth, color, surface texture, and transparency of the restorations, and features during the 1st and 3rd postoperative months. In the 6th month, the comparative results indicated that the experimental group continued to exhibit superior outcomes to the control group in terms of the shape, color, surface texture, and transparency of the restorations, as well as the characteristics of the teeth. Additionally, the experimental group demonstrated significantly fewer gingival alterations than the control group at 1 month, 3 months, and 6 months post-procedure, with this difference being statistically significant. Furthermore, the combination of 3D printing technology and restorative techniques was utilized, resulting in consistent patient satisfaction. CONCLUSION: Digitalisation plays an important role in anterior aesthetic restorations. The use of digital technology to manage the entire process of anterior cosmetic restorations can improve restorative results, reduce the number of follow-up appointments, shorten consultation time, and achieve better patient satisfaction.

Digital planning and guided dual technique in esthetic crown lengthening: a randomized controlled clinical trial.

OBJECTIVES: The present study aimed to compare the guided dual technique with the conventional technique in esthetic crown lengthening (ECL). MATERIALS AND METHODS: The trial registration number is NCT04922086. Twenty-four participants diagnosed with altered passive eruption (APE) type I subcategory B were selected and allocated into two groups. In the control group (n = 12), the ECL procedure was planned by clinical examination and transgingival probing; in the test group (n = 12), the ECL procedure was carried out using digital planning and a double guide. Clinical parameters were assessed at baseline, immediately after the intervention (IAI), and at 4, 8, and 12 months of follow-up. RESULTS: The clinical crown length (CCL) mean at baseline was 8.09 mm (± 0.77) and increased significantly to 9.92 mm (± 0.62) IAI, with minimal significant reduction after 12 months (9.47 mm [± 0.60]) in the control group. Similarly, in the test group, the mean CCL at baseline was 8.04 mm (± 0.69) and increased significantly to 9.94 mm (± 0.57) IAI, with minimal reduction after 12 months (9.35 mm [± 0.80]). No differences were found between the mean CCL determined in the digital planning and after 12 months. No correlation was found between gingival thickness and gingival margin stability. High esthetic satisfaction was demonstrated by participants/specialists without differences between groups. CONCLUSIONS: In conclusion, the guided dual technique was as effective as the conventional technique for treatment of APE, with stable results after 12 months of follow-up. CLINICAL RELEVANCE: The guided dual technique aims to transfer both the gingival and bone resection planned position to facilitate the ECL surgical procedure and increase treatment predictability.

Biological evaluation of indirect restorations in endodontically treated posterior teeth with deeply located proximal margins following deep margin elevation versus surgical crown lengthening: a randomized controlled trial.

OBJECTIVE: The current clinical trial was conducted to evaluate the effect of proximal indirect restorations in endodontically treated posterior teeth with deeply located margins following deep margin elevation compared to surgical crown lengthening. MATERIAL AND METHODS: Deep proximal cavities in endodontically treated posterior teeth were randomly assigned into two groups; deep margin elevation (DME) or crown lengthening (CL). The clinical attachment level (CAL), probing depth (PD), bleeding on probing (BOP), crestal bone level (CBL), and secondary caries were evaluated at the baseline, 1, 3, 6, 9, and 12 months. RESULTS: A total of 20 proximal cavities were included in the study; there was no significant difference between the two groups regarding mean CAL values at the baseline and 1 month, while there was a significant difference between the two groups in all other periods. Regarding the PD, there was no statistical significance between the two groups except at 9 and 12 months, where CL showed higher mean PD values than DME. There was no statistically significant difference in BOP or CBL between the two groups. CONCLUSIONS: DME and CL are considered clinically successful with favorable biologic responses. CLINICAL RELEVANCE: The deep margin elevation approach could provide a more conservative solution when relocating deeply seated cervical margins in a more coronal position. DME reduced the number of visits and time needed for the restoration of endodontically treated teeth. Surgical crown lengthening remains a gold standard procedure in the re-establishment of the supracrestal tissue attachment, especially in cases where cervical margins are beyond the elevation capacity.

Effect of apical root resection, orthodontic extrusion, and surgical crown lengthening on load capability.

OBJECTIVES: This study aims to investigate the load-to-fracture of procedures changing crown-to-root ratio (RCRR) aimed to restore severely damaged upper central incisors to avoid tooth extraction compared to implant placement. There is no evidence on load capability after apical root resection (AR), orthodontic extrusion (OE), and surgical crown lengthening (SCL) in respect to RCRR, respectively. MATERIAL AND METHODS: Human maxillary central incisors were endodontically treated, decoronated, and divided into 4 groups (n = 48). The following specimen preparation was performed: (I) adhesive core-and-post build-up (control), (II) as (I) and 2 mm apical root resection (AR), (III) before adhesive core-and-post build-up teeth were shortened 2 mm coronally (OE) (IV) as (I), but specimens were embedded 4 mm instead of 2 mm below the CEJ (SCL), group (V) implant-borne restoration with individual all-ceramic abutments (n = 12; ∅4.1/l = 12 mm) (IBR). All specimens received all-ceramic crowns, thermo-mechanical (TML), and subsequent linear loading (LL) until failure. RCRR were calculated and log-rank, Kruskal-Wallis, Mann-Whitney U, ANOVA, and chi-square tests applied (p = 0.05). RESULTS: Fracture loads after subsequent LL differed significantly (p = 0.001) between groups, while implants showed the highest values. Fmax median (min/max) were as follows: (I) 252 (204/542), (II) 293 (243/443), (III) 253 (183/371), (IV) 195 (140/274), and (V) 446 (370/539). Pair-wise comparison showed significant differences (p = 0.001) between group I/IV and group V, I, and IV (p = 0.045), II and IV (p = 0.001), and III compared to IV (p = 0.033), respectively. RCRR below 1 significantly increased load capability compared to RCRR = 1. CONCLUSIONS: OE appears to preferably ensure biomechanical stability of teeth that are endodontically treated and receive core-and-post and crown placement compared to SCL. AR has no adverse biomechanical impact. RCRR < 1 is biomechanically beneficial. CLINICAL RELEVANCE: For endodontically treated and restored teeth, orthodontic extrusion should be preferred compared to surgical crown lengthening prior single-crown restoration. As orthodontic extrusion, apical root resection has no adverse effect on load capability. Single-crown implant-borne restorations are most load capable.

The crown lengthening double guide and the digital Perio analysis.

OBJECTIVE: This article describes a surgical crown lengthening double guide, which was digitally obtained to improve diagnosis, treatment outcome, and follow-up. CLINICAL CONSIDERATIONS: The rehabilitation of anterior dental esthetics should involve interdisciplinary and facially driven planning for achieving pleasant long-term outcomes. Surgical crown lengthening is one of the most common periodontal surgery, which can be assisted by digital tools to improve surgical planning and follow-up. CONCLUSION: The double guide for surgical crown lengthening allows the proper management of hard and soft tissues for achieving a predefined goal based on biological requirements and facially driven planning. In addition, the digital quality control allows the follow-up compared with the pre-operative condition and planned treatment plan. CLINICAL SIGNIFICANCE: The use of digital tools allow the clinician to develop a facially driven planning with proper communication with the team and patient, leading to a shorter, more predictable, and less invasive surgical technique, reducing postoperative inflammation and increasing patient comfort.

Digitally planned surgical crown lengthening in the esthetic zone.

Surgical crown lengthening is one of the most common surgical procedures in periodontal practice. It is divided into functional and esthetic surgical crown lengthening. In general, surgical crown lengthening is a predictable periodontal surgical procedure. Its most common complication is excessive regression of the dentoalveolar complex coronally. Esthetic surgical crown lengthening can be performed predictably through prior digital planning, minimizing the risk of potential complications such as excessive regression of the dentoalveolar complex coronally. The present study reported in this article is a clinical case of surgical crown lengthening with digital planning to derive practical recommendations.

[How long does a tooth last after a surgical crown lengthening?] / Hoe lang gaat een gebitselement mee na een chirurgische kroonverlenging?

The presence of subgingival pathology, such as a deep secondary caries lesion, a fracture, an already existing restoration that needs to be replaced or the presence of a resorption defect, can constitute a difficult starting situation for the preservation of a tooth. How to deal with such a situation has been a topic of discussion for years. Surgical crown lengthening is one of the first and classic treatment options that is often chosen in such cases. Crown lengthening is a periodontal surgical technique to obtain extra supra crestal clinical crown length. The question is, what is the long-term prognosis of teeth after surgical crown lengthening. To answer this question, a review of the literature was carried out looking for clinical studies examining survival. Four studies with a follow-up of at least 5 years were included. The factors that adversely affect survival of the tooth after the crown lengthening are an unfavourable crown-root ratio, insufficient plaque control and moderate ability to keep the restoration clean.

The use of diode laser in esthetic crown lengthening: a randomized controlled clinical trial.

This clinical trial assessed patient comfort, satisfaction, and the achievement and maintenance of ideal gingival margin levels using laser compared to conventional surgery in sculpting the soft tissues during esthetic crown lengthening. Eighteen patients with altered passive eruption were treated in a randomized split-mouth design by laser or scalpel crown-lengthening surgery. Patients were evaluated for intra- and postoperative pain and bleeding at 3 and 7 days. Clinical parameters including clinical crown length, probing depth, plaque index, bleeding on probing, and clinical attachment level were recorded at baseline, 3 and 6 months postoperatively. A gradual reduction in postoperative pain was recorded for both sides with no statistically significant difference at 3 (scalpel: 4.4 ± 1.33, laser: 4.8 ± 1.34; p = 0.088) and 7 days (scalpel: 1.8 ± 0.94, laser: 1.8 ± 1.10; p = 0.655). A statistically significant gain of coronal tooth structure was observed at 1, 3, and 6 months. Stability in the post-crown-lengthening level of the gingival margin was achieved one month following the procedure with no significant changes in the following months. All patients reflected acceptable results based on clinical evaluation and patient-reported outcomes. The diode laser can be used effectively as an alternative to the scalpel for the management of altered gingival contour. CLINICAL SIGNIFICANCE : This study demonstrated that a diode laser is an effective tool for the management of cases with altered passive eruption. In addition, it gives insight to practitioners regarding the timing of esthetic restorative procedures and emphasizes the preservation of the gingival complex dimensions.

Periodontal plastic surgery for esthetic crown lengthening by using data merging and a CAD-CAM surgical guide.

This article introduced a digital workflow by using data merging and a computer-aided design and computer-aided manufacturing (CAD-CAM) milled surgical guide for an esthetic crown lengthening procedure. The superimposition of intraoral scanning, digital photographs, cone beam computed tomography, and a CAD-CAM surgical guide should increase the predictability of esthetic crown lengthening surgery.

Success rate of fractured teeth receiving modified crown lengthening surgery and restorations.

BACKGROUND: Whether to preserve a structurally compromised tooth or remove it is a dilemma often encountered by clinicians. The aim of this study was to assess the long-term success rate of fractured teeth preserved by modified crown lengthening surgery and restorations. METHODS: Thirty-nine patients with a total of 45 fractured teeth who had received modified crown lengthening surgery were recruited and examined. Numbers of teeth lost were recorded, and the criteria for successful teeth were defined. Kaplan-Meier estimator was used to determine the success rate. Possible risk factors were compared between successful and unsuccessful groups by a Cox regression analysis to explore the potential predictors of failure with a significant level at α = 0.05. RESULTS: The mean ± SD of success time without considering variants was 6.2 ± 0.6 years (95% CI 5.1-7.7). The mean survival rates ± SD at 1.0-, 2.0-, 3.0-, 5.0-, 7.0-, and 9.0-year intervals was 97.8 ± 2.2%, 92.2 ± 4.4%, 72.8 ± 7.9%, 68.2 ± 8.6%, 60.7 ± 10.5%, and 40.4 ± 13.6%, respectively. Failure cases in teeth with poor plaque control and step-shaped fracture margin were significantly more than those with good plaque control and knife-shaped fracture margin (HR = 7.237, p = 0.011; HR = 15.399, p = 0.006; respectively). CONCLUSIONS: Fractured teeth treated with modified crown lengthening surgery are anticipated to have a high clinical success rate for 6.2 ± 0.6 years. Plaque control and fracture morphology appeared to be significantly associated with the success of the multidisciplinary treatment approach.

New approach to expedite the delivery of the final crowns for teeth requiring crown lengthening surgery: a pilot study.

BACKGROUND: The healing period from crown lengthening procedures (CLPs) often delays the final crown delivery. This study aimed to explore the feasibility of a new approach expediting the delivery of the final crowns for teeth requiring CLPs. METHODS: Teeth requiring CLPs and single-crown restorations between the canine and the second molar were included. After the initial tooth preparation, a CLP was performed. In the experimental group, the final tooth preparation and final impression were made during the CLP; the final crown was then delivered at the suture-removal appointment. In the control group, the final impression was made 8 weeks after the CLP. The level of gingival margin (GM), pocket depth (PD), and crestal bone levels (CBLs) were compared between the two groups before CLPs (T0), at delivery of the crowns (T1), and at 12 months in function (T2). RESULTS: Twenty-one lithium-disilicate crowns were delivered to 20 subjects and followed up. The mean interval between the CLPs and the delivery of crowns was 2.5 weeks for the experimental group and 12 weeks for the control group. No significant differences were observed between the two groups in the level of GM, PD, and CBLs at each time point. No significant treatment difference in crestal bone loss was observed between the two groups at T2 (Experimental = -0.11 mm, Control = -0.03 mm; p = 0.67). CONCLUSION: Making the final tooth preparation and the final impression at the CLP significantly reduced the time between the CLP and the delivery of the final crown and showed comparable clinical outcomes.

[Healing of the dento-gingival junction following modified crown lengthening procedure in beagle dogs].

OBJECTIVE: To evaluate the type of wound healing following modified crown lengthening surgery in dog model to provide a biological basis for its clinical application. METHODS: Flap surgery, traditional crown lengthening procedure and modified crown lengthening procedure were performed on the right maxillary central incisor, the left maxillary central incisor and the left maxillary first lateral incisor respectively of five male beagle dogs. The right maxillary first lateral incisors with no surgical intervention were used as controls. Thirty-six weeks after the experimental procedure, tissue blocks were harvested and prepared for histological examination and analysis. RESULTS: Histometric examination of buccolingual sections stained with hematoxylin-eosin demonstrated that the type of wound healing in the flap surgery group was re-attachment, similar to the control group. For the traditional crown lengthening surgery group, all of the five beagle dogs had lamellar cementum defects on root surface, the wound healing of four beagle dogs was new attachment accompanied by new cementum formation at cementum defect areas and the suprac-restal connective tissue was functionally oriented perpendicular to the new cementum. The wound healing of the other beagle dog was long junctional epithelial attachment, in which the junctional epithelium extended to the apical terminus of the cementum defect. In the modified crown lengthening surgery group, four beagle dogs had cementum defects on root surface (two lamellar cementum defects and two shallow platform-like cementum defects), the wound healing of three beagle dogs was new attachment, however, the supracrestal connective tissue was parallel to the root surface. The type of wound healing of another one beagle dog was long junctional epithelial attachment. Wound healing of one beagle dog in this group could not be characterized due to incomplete dissection. CONCLUSION: Wound healing in the modified crown lengthening surgery group was similar to the traditional crown lengthening surgery group, and two types of wound healing were observed: new attachment and long junctional epithelium attachment. Neither type of root treatment procedure (root planing or root reshaping) nor root surface defect pattern (the lamellar cementum defect or shallow platform-like cementum defect) influenced the observed type of wound healing.

Virtual Planning and Rapid 3D Prototyping Surgical Guide for Anterior Crown Lengthening Surgery: A Clinical Case Report.

Progress with additive 3D printing is revolutionizing biomaterial manufacturing, including clinical dentistry and prosthodontics. Among the several 3D additive printing technologies, stereolithography is very popular as it utilizes light-activated resin for precise resolution. A simplified digital technique was used to fabricate two designs of a surgical guide for crown lengthening. Two cases are presented that utilized digital imaging and communications in medicine (DICOM) files obtained with computed tomography (CT) imaging and processed using four CAD software (Blue Sky Plan, Exocad, Meshmixer and 3D Slicer). The final models were converted to standard tessellation (STL) files and the guides were 3D printed with an additive stereolithography (SLA) printer. The first case was fabricated with a bone model from cone beam computed tomography (CBCT) data, and the second case was generated with intraoral and wax-up scans alone. Both methods appear to be equally effective compared to using a conventional method of guide frabication. However, proximal bone reduction was a concern with both designs. Digitally fabricated 3D printed surgical guide for crown lengthening has merit and a practical design is needed for future clinical validation.

A systematic scoring system to determine the long-term prognosis for severely damaged teeth.

Many of the criteria commonly considered in treatment planning for severely damaged teeth are well known to clinicians. However, a systematic approach to decision-making is lacking. The purpose of this article is to introduce a quantitative systematic risk assessment scoring system (RASS) to determine the long-term prognosis for severely damaged teeth based on several important factors. Before any treatment decision is made, the dentist should take into account the role of systemic parameters such as the medical condition of the patient, smoking status, psychological factors, patient expectations with regard to the duration and overall cost of treatment, and periodontal health. In the assessment of local factors, emphasis should be placed on 5 parameters: crown to root ratio, root condition, risk of furcation involvement, complexity of the final restoration, and esthetic results. In the proposed RASS, each of these parameters is ranked using 4 color-coded levels of risk: optimal (green), favorable (blue), unfavorable (yellow), or hopeless (red). The presence of even 1 parameter in the red zone is sufficient to consider tooth extraction. If no parameter is in the red zone, the final decision should be made after the possible effects of all of the clinical conditions are weighed and the overall risk of treatment failure is determined. Clinical decision-making with regard to the preservation or extraction of severely damaged teeth is a challenging, multifactorial process. The RASS introduced in this article focuses on 5 main factors to simplify and organize the decision-making process; however, many other parameters may affect the final treatment decision. Moreover, no decision-making system can be definitively applied to all clinical scenarios, and the entire process depends on the knowledge, experience, and expertise of the clinician.

Diagnostic Mock-Up as a Surgical Reduction Guide for Crown Lengthening: Technique Description and Case Report.

Background and Objectives: The report describes a technique using a diagnostic mock-up as a crown-lengthening surgical guide to improve the gingival architecture. Materials and Methods: The patient's primary concern was improving her smile due to her "gummy smile" and short clinical crowns. After clinical evaluation, surgical crown lengthening accompanied by maxillary central full-coverage single-unit prostheses and lateral incisor veneers was recommended. The diagnostic mock-up was placed in the patient's maxillary anterior region and used as a soft tissue reduction guide for the gingivectomy. Once the planned gingival architecture was achieved, a flap was reflected to proceed with ostectomy in order to obtain an appropriate alveolar bone crest level using the overlay. After six months, all-ceramic crowns and porcelain veneers were provided as permanent restorations. Results: A diagnostic mock-up fabricated with a putty guide directly from the diagnostic wax-up can be an adequate surgical guide for crown-lengthening procedures. The diagnostic wax-up was used to fabricate the diagnostic mock-up. These results suggested that it can be used as a crown-lengthening surgical guide to modify the gingival architecture. Several advantages of the overlay used in the aesthetic complex case include: (1) providing a preview of potential restorative outcomes, (2) allowing for the appropriate positioning of gingival margins and the desired alveolar bone crest level for the crown-lengthening procedure, and (3) serving as a provisional restoration after surgery. Conclusions: The use of a diagnostic mock-up, which was based on a diagnostic wax-up, as the surgical guide resulted in successful crown lengthening and provisional restorations. Thus, a diagnostic overlay can be a viable option as a surgical guide for crown lengthening.