Volumetric changes at implant sites: A systematic appraisal of traditional methods and optical scanning-based digital technologies

Risk indicators for gingival recession in the esthetic zone: A cross-sectional clinical, tomographic, and ultrasonographic study

BACKGROUND

To evaluate the risk indicators associated with midfacial gingival recessions (GR) in the natural dentition esthetic regions.

METHODS

Cone-beam computed tomography (CBCT) results of thirty-seven subjects presenting with 268 eligible teeth were included in the cross-sectional study. Clinical measurements included presence/absence of midfacial GR; the depth of the midfacial, mesial, and distal gingival recession; the recession type (RT); keratinized tissue width (KT); and attached gingiva width (AG). Questionnaires were utilized to capture patient-reported esthetics and dental hypersensitivity for each study tooth. Buccal bone dehiscence (cBBD) and buccal bone thickness (cBBT) were measured on the CBCT scans. High-frequency ultrasonography was performed to assess gingival thickness (GT) and buccal bone dehiscence (uBBD). Intraoral optical scanning was obtained to quantify the buccolingual position of each study site (3D profile analysis). Multilevel logistic regression analyses with generalized estimation equations were performed to assess the factors associated with the conditions of interest.

RESULTS

The presence of midfacial GR was significantly associated with the history of periodontal treatment for pocket reduction (OR 7.99, p = 0.006), KT (OR 0.62, p < 0.001), cBBD (OR 2.30, p = 0.015), GT 1.5 mm from the gingival margin (OR 0.18, p = 0.04) and 3D profile 1 mm from the gingival margin (OR 1.04, p = 0.001). The depth of midfacial GR was significantly correlated to previous history of periodontal treatment (OR 0.96, p = 0.001), KT (OR -0.18, p < 0.001), presence of bone fenestration (OR 0.24, p = 0.044), and cBBD (OR 0.43, p < 0.001). The depth of midfacial GR was also the only factor associated with patient-reported esthetics (OR -3.38, p = 0.022), while KT (OR 0.77, p = 0.018) and AG (OR 0.82, p = 0.047) were significantly correlated with patient-reported dental hypersensitivity.

CONCLUSIONS

Several risk indicators of midfacial and interproximal GR in the esthetic region were identified. The use of imaging technologies allowed for detection of parameters associated with the conditions of interest, and, therefore, their incorporation in future clinical studies is advocated. Ultrasonography could be preferred over CBCT for a noninvasive assessment of periodontal phenotype.

Influence of immediate postoperative gingival thickness and gingival margin position on the outcomes of root coverage therapy: A 6 months prospective case series study using 3D digital measuring methods

BACKGROUND

To assess linear and volumetric changes following the treatment of gingival recessions (GRs) by means of a modified coronally advanced tunnel technique combined with acellular dermal matrix (MTUN + ADM).

MATERIALS AND METHODS

Patients presenting GR type 1 (RT1) GRs underwent root coverage surgery consisting of MTUN + ADM. Clinical measurements were made, and intraoral scans were obtained at baseline, postoperatively, and 6 weeks, 3 and 6 months after surgery, to evaluate changes in probing depth (PD), keratinized tissue width (KTW), recession depth (RD), recession area (RA), marginal gingival thickness (MGT), and mucosal volume (MV). The impact of patient-level and surgical-site variables upon percentage root coverage (% RC) and the likelihood of achieving complete root coverage (CRC) were explored.

RESULTS

A total of 20 patients (n = 47 teeth) were treated. After 6 months, RD and RA decreased, while KTW, MGT, and MV increased. The mean % RC was 93% at 6 months and CRC was found on 72.3% of the sites at 6 months. The postoperative MGT changes at 1.5 and 3 mm were significantly correlated to % RC and CRC at 6 months. Each additional mm of postoperative gain of gingival thickness resulted in a 4-fold increase in the probability of achieving CRC. Additionally, gingival margin positioned ≥0.5 mm coronal to the cementoenamel junction immediately after surgery was a strong predictor of CRC.

CONCLUSIONS

The MGT gain at 1.5 and 3 mm achieved in the immediate postoperative period is a significant predictor of CRC at 6 months when treating multiple GRs via MTUN + ADM.

CLINICAL SIGNIFICANCE

The Scientific rationale for the study relies on the lack of 3D digital measuring tools in the assessment of soft tissue healing dynamics after root coverage therapy. The principal findings of this study can be summarized as follows: tooth type, tooth position, and post-operative gingival margin position and gingival thickness and volume changes are predictors of CRC. Therefore, the practical implications are that the more thickness and more coronal advancement achieved immediately after root coverage surgery, the higher chance of achieving CRC.

Comparison of morbidity at the donor site and clinical efficacy at the recipient site between two different connective tissue graft harvesting techniques from the palate: A randomized clinical trial

Background

This study was conducted to compare the pain levels in patients and the clinical efficacy of grafts obtained using two techniques, namely de-epithelialized gingival graft (DGG) and subepithelial connective tissue graft (SCTG), in combination with coronally advanced flap (CAF) for the treatment of multiple adjacent gingival recessions.

Methods

Twelve patients were treated using DGG+CAF on one side and SCTG+CAF on the other. The patients' pain levels at the surgical site, the number of analgesics taken on days 3 and 7, the mean root coverage (MRC), the percentage of complete root coverage (CRC), color match, and gingival thickness (GT) at the graft recipient site were evaluated 6 months after surgery.

Results

The total number of analgesics taken during the 7-day period after surgery and pain levels at the surgical site from day 3 to day 7 were significantly higher in the DGG+CAF group compared to the SCTG+CAF group (P=0.001). In the 6-month follow-up, color match and CRC were significantly higher in the SCTG+CAF group, while GT was significantly higher in the DGG+CAF group. There was no significant difference in MRC between the two groups.

Conclusion

The pain and analgesic consumption levels were higher in the DGG+CAF group compared to the SCTG+CAF group, and the recipient site had a weaker color match. However, this technique can lead to a greater increase in the thickness of the grafted area.

Do soft tissue augmentation techniques provide stable and favorable peri-implant conditions in the medium and long term? A systematic review

OBJECTIVES

To review the available literature on the medium- and long-term effects of soft tissue augmentation (STA) at implant sites and to explore the effects of the different approaches on clinical-, patient-reported, and health-related parameters.

MATERIALS AND METHODS

A comprehensive electronic and manual search was performed to identify prospective clinical studies that assessed the medium- and long-term (≥36 months) outcomes following STA, including number of sites maintaining peri-implant health and number of sites developing peri-implant disease, incidence of complications, stability of the clinical, volumetric, and radiographic parameters, and patient-reported outcome measures (PROMs).

RESULTS

Fifteen studies were included in the qualitative analysis. STA was performed with either a bilaminar- or an apically positioned flap (APF) approach, in combination with autogenous grafts (free gingival graft [FGG] and connective tissue graft [CTG]) or substitutes (acellular dermal matrix [ADM] and xenogeneic cross-linked collagen matrix [CCM]). An overall high survival rate was observed. Most of the augmented implant sites maintained peri-implant health in the medium and long term, with the incidence of peri-implant mucositis and peri-implantitis ranging from 0% to 50% and from 0% to 7.14%, respectively. The position of the soft tissue margin following APF + FGG and bilaminar approaches involving CTG or CCM was found to be stable over time. No substantial changes were reported for plaque score/index, bleeding on probing/bleeding index, and probing depth between early time points and following visits. CTG-based STA procedures resulted in a stable or increased dimension of keratinized mucosa width (KMW) and mucosal thickness (MT)/volumetric outcomes over time, when compared with early follow-ups. Most of the included studies described stable marginal bone levels at the grafted implant sites over time. No substantial changes for patient-reported outcomes and professionally assessed esthetic results were reported at different time points.

CONCLUSIONS

Implants that received STA showed overall high survival rate and relatively low incidence of peri-implantitis in the medium and long term. Augmented sites seem to maintain the level of soft tissue margin and marginal bone over time, while non-augmented implants may exhibit apical shift of the soft tissue margin. The overall favorable early outcomes obtained with STA are maintained in the medium and long term, with an increase in KMW and MT that may be expected over time at CTG-augmented sites.

Overview of Ultrasound in Dentistry for Advancing Research Methodology and Patient Care Quality with Emphasis on Periodontal/Peri-implant Applications

BACKGROUND

Ultrasound is a non-invasive, cross-sectional imaging technique emerging in dentistry. It is an adjunct tool for diagnosing pathologies in the oral cavity that overcomes some limitations of current methodologies, including direct clinical examination, 2D radiographs, and cone beam computerized tomography. Increasing demand for soft tissue imaging has led to continuous improvements on transducer miniaturization and spatial resolution. The aims of this study are (1) to create a comprehensive overview of the current literature of ultrasonic imaging relating to dentistry, and (2) to provide a view onto investigations with immediate, intermediate, and long-term impact in periodontology and implantology.

METHODS

A rapid literature review was performed using two broad searches conducted in the PubMed database, yielding 576 and 757 citations, respectively. A rating was established within a citation software (EndNote) using a 5-star classification. The broad search with 757 citations allowed for high sensitivity whereas the subsequent rating added specificity.

RESULTS

A critical review of the clinical applications of ultrasound in dentistry was provided with a focus on applications in periodontology and implantology. The role of ultrasound as a developing dental diagnostic tool was reviewed. Specific uses such as soft and hard tissue imaging, longitudinal monitoring, as well as anatomic and physiological evaluation were discussed.

CONCLUSIONS

Future efforts should be directed towards the transition of ultrasonography from a research tool to a clinical tool. Moreover, a dedicated effort is needed to introduce ultrasonic imaging to dental education and the dental community to ultimately improve the quality of patient care.

Keratinized mucosa width assessment at implant sites using high-frequency ultrasonography

BACKGROUND

The aim of this study was to describe the application of high-frequency ultrasonography (HFUS) for assessing keratinized mucosa (KM) width at implant sites.

METHODS

KM width was measured at 28 implant sites exhibiting a peri-implant soft tissue dehiscence at baseline and 12 months after soft tissue augmentation. KM width assessment was performed with a periodontal probe [clinical assessment (clKM)] and with HFUS, based on the echointensity of the keratinized epithelium compared to the adjacent structures. KM width measurements on ultrasound scans were performed linearly (lnKM) and along the soft tissue profile [surface distance (sdKM)].

RESULTS

No statistically significant differences were observed between clKM, lnKM, and sdKM at baseline, while at 12 months, sdKM (5.313 ± 1.188 mm) was significantly higher than clKM (3.98 ± 1.25 mm) and lnKM (4.068 ± 1.197 mm) (P < 0.001 for both comparisons). A linear relationship between mucosal thickness (MT) and the difference between sdKM and lnKM was observed. In 95.2% of cases with MT > 2.51 mm, the discrepancy between sdKM and lnKM was at least 1 mm.

CONCLUSIONS

HFUS is a noninvasive and valuable tool for measure KM width at implant site. Evaluating KM width along the soft tissue profile as a surface distance may improve the accuracy of the assessment.

Coronally advanced flap versus tunnel technique for the treatment of peri-implant soft tissue dehiscences with the connective tissue graft: A randomized, controlled clinical trial

AIM

To evaluate the efficacy of coronally advanced flap (CAF) versus tunnel technique (TUN) in covering isolated mid-facial peri-implant soft tissue dehiscences (PSTDs).

MATERIALS AND METHODS

Twenty-eight participants presenting with isolated non-molar implants exhibiting PSTDs were enrolled and randomized to receive either CAF or TUN, both with a connective tissue graft (CTG). The primary outcome of the study was the percentage of mean PSTD coverage at 12 months. Secondary endpoints included the frequency of complete PSTD coverage, changes in keratinized mucosa width (KMW) and horizontal mucosal thickness (MT), as assessed with transgingival probing, 3D optical scanning and ultrasonography, professional aesthetic evaluation and patient-reported outcome measures (PROMs).

RESULTS

At 12 months, the mean PSTD coverage of the CAF and TUN groups was 90.23% and 59.76%, respectively (p = .03). CAF-treated sites showed a substantially higher frequency of complete PSTD coverage (p = .07), together with significantly greater gain of KMW (p = .01), increase in MT (p = .02), volumetric gain (p < .01) and professional aesthetic outcomes (p = .01). Both interventions showed an improvement in patient-reported aesthetics and a reduction of the anxiety related to the appearance of the implant compared to baseline, with the CAF group obtaining significantly higher scores (p = .03 for both PROMs).

CONCLUSIONS

CAF + CTG resulted in superior PSTD coverage outcomes, greater gain in KMW and MT, and better PROMs than TUN + CTG for the treatment of isolated PSTDs (ClinicalTrials.gov NCT03498911).

Alveolar ridge preservation: Complications and cost-effectiveness

Alveolar ridge preservation is routinely indicated in clinical practice with the purpose of attenuating postextraction ridge atrophy. Over the past two decades numerous clinical studies and reviews on this topic have populated the literature. In recent years the focus has primarily been on analyzing efficacy outcomes pertaining to postextraction dimensional changes, whereas other relevant facets of alveolar ridge preservation therapy have remained unexplored. With this premise, we carried out a comprehensive evidence-based assessment of the complications associated with different modalities of alveolar ridge preservation and modeled the cost-effectiveness of different therapeutic modalities as a function of changes in ridge width and height. We conclude that, among allogeneic and xenogeneic bone graft materials, increased expenditure does not translate into increased effectiveness of alveolar ridge preservation therapy. On the other hand, a significant association between expenditure on a barrier membrane and reduced horizontal and vertical ridge resorption was observed, though only to a certain degree, beyond which the return on investment was significantly diminished.

Vertical soft tissue augmentation to treat implant esthetic complications: A prospective clinical and volumetric case series

INTRODUCTION

Challenging implant esthetic complications are often characterized by implant malpositioning and interproximal attachment loss of the adjacent teeth. However, limited evidence is available on the treatment of these conditions. The aim of this study was to evaluate the clinical, volumetric, and patient-reported outcome following treatment of peri-implant soft tissue dehiscences (PSTDs) exhibiting interproximal attachment loss on adjacent teeth, performed through vertical soft tissue augmentation with implant submersion.

METHODS

Ten subjects with isolated PSTD in the anterior maxilla characterized by adjacent dentition exhibiting interproximal attachment loss were consecutively enrolled and treated with horizontal and vertical soft tissue augmentation, involving crown and abutment removal, two connective tissue grafts, and submerge healing. Clinical outcomes of interest included mean PSTD coverage, mean PSTD reduction, clinical attachment level (CAL) gain at the implant and adjacent sites and soft tissue phenotype modifications at 1 year. Optical scanning was used for assessing volumetric changes. Professional assessment of esthetic outcomes was performed using the Implant Dehiscence coverage Esthetic Score (IDES), while patient-reported esthetic assessment involved a 0-10 visual analogue scale.

RESULTS

The mean PSTD depth reduction and mean PSTD coverage at 1 year were 2.25 mm, and 85.14%, respectively. A mean keratinized tissue width (KTW) gain of 1.15 mm was observed, while the mean gain in mucosal thickness (MT) was 1.58 mm. A mean CAL gain of 1.45 mm was obtained at the interproximal aspect of the adjacent dentition at 1 year. Greater linear dimensional (LD) changes were observed at the midfacial aspect of the implant compared to the interproximal sites. The mean final IDES was 6.90 points, while patient-reported esthetic evaluation was 8.83 points.

CONCLUSIONS

The present study demonstrated that vertical soft tissue augmentation with a submerged healing is an effective treatment approach for the treatment of challenging PSTDs with adjacent dentition exhibiting interproximal attachment loss. This technique can be effective in resolution of esthetic complications in most cases, providing a substantial gain in interproximal attachment levels at the adjacent dentition.

[Measuring methods of volumetric changes of soft tissues at dental implants site and tooth recessions site]

The article is a review of literature on various methods for measuring gingival thickness at implant site and tooth recession. The purpose of the study was to analyze existing methods for assessing volumetric changes in soft tissues based on literature data and give recommendations on the choice of methods. The authors analyzed available methods and identified limitations and recommendations for the use of different methods. The literature review is also helpful to identify promising methods for assessing changes in soft tissue volume, which may help authors of future studies with method selection.

Design of customized soft tissue substitutes for anterior single-tooth and posterior double-tooth defects: An in vitro study

OBJECTIVE

This study aims to validate the standardized procedure for designing soft tissue substitutes (STS) adapted to optimally fit single-tooth defects in the anterior jaws and double-tooth defects in the posterior jaw and to compare mathematically modeled average shapes.

MATERIALS AND METHODS

Casts from 35 patients with 17 single-tooth defects in anterior region and 21 double-tooth defects in posterior region were scanned. STS were designed and sectioned in 3D slices meshes. Thickness values were documented respecting mesial-distal and buccal-lingual orientations. Graphs were embedded into images, and hierarchical clustering was applied to group STS according to shape and thickness.

RESULTS

STS clustered into two groups per defect type. For anterior single defects, STS (n = 4) were either a small and thin oval: 7 mm buccal-lingual, 4-5 mm mesial-distal direction and 1.1-1.5 mm thick or a larger oval (n = 13): 9 mm buccal-lingual, 5-7 mm mesial-distal and 1.6 m thick. For posterior double tooth defects, STS (n = 10) were either narrow, long and thick: 6-7 mm buccal-lingual, 16-20 mm mesial-distal and 2.2 thick or a wide, thinner rectangle (n = 11): 9-11 mm buccal-lingual, 12-14 mm mesial-distal and 1.1-1.5 mm thick.

CONCLUSIONS

The study validated the standardized digital method to design grafts for soft tissue volume augmentation and identified four average shapes for anterior single-tooth and posterior double-tooth soft tissue defects.

CLINICAL SIGNIFICANCE

We developed and validated a standardized digital method to design an optimal geometrical shape of a soft tissue substitute for oral volume augmentation and combined it with mathematical modeling to identify average shapes for single-interior, and double-posterior tooth defects. The identified average shapes offer the possibility to produce better-fitted xenografts or synthetic STS blocks requiring minimal chair-side adaptation leading to reduced clinical time and patient discomfort and potentially improving soft tissue volume augmentation outcomes.

Recombinant human platelet-derived growth factor improves root coverage of a collagen matrix for multiple adjacent gingival recessions: A triple-blinded, randomized, placebo-controlled trial

AIM

To evaluate the efficacy of recombinant human platelet-derived growth factor (rhPDGF)-BB combined with a cross-linked collagen matrix (CCM) for the treatment of multiple adjacent gingival recession type 1 defects (MAGRs) in combination with the coronally advanced flap (CAF).

MATERIALS AND METHODS

Thirty patients were enrolled in this triple-blind, randomized, placebo-controlled trial and treated with either CAF + CCM + rhPDGF, or CAF + CCM + saline. The primary outcome was mean root coverage (mRC) at 6 months. Complete root coverage, gain in gingival thickness (GT), keratinized tissue width, volumetric and ultrasonographic changes, and patient-reported outcome measures were also assessed. Mixed-modelling regression analyses were used for statistical comparisons.

RESULTS

At 6 months, the mRC of the CCM + rhPDGF and CCM alone groups were 88.25% and 77.72%, respectively (p = .02). A significant gain in GT was consistently observed for both treatment arms, and more so for the patients receiving the matrix containing rhPDGF through time (0.51 vs. 0.80 mm, on average, p = .01). The rhPDGF + CCM treated patients presented greater volume gain, higher soft tissue thickness, and a superior aesthetic score.

CONCLUSION

rhPDGF enhances the clinical, volumetric, and aesthetic outcomes of MAGRs above the results achieved with CAF + CCM alone (ClinicalTrials.gov NCT04462237).

Intraoral Scanners for In Vivo 3D Imaging of the Gingiva and the Alveolar Process

This study aimed to assess the reliability of two intraoral surface scanners for the representation of the alveolar process in vivo. Complete maxillary scans (CS 3600, Carestream and TRIOS 3, 3Shape) were repeatedly obtained from 13 fully dentate individuals. Scanner precision and agreement were tested using 3D surface superimpositions on the following reference areas: the buccal front teeth area, the entire dental arch, the entire alveolar process, or single teeth by applying an iterative closest point algorithm. Following each superimposition, the mean absolute distance (MAD) between predefined 3D model surfaces was calculated. Outcomes were analyzed through non-parametric statistics and the visualization of color-coded distance maps. When superimpositions were performed on the alveolar process, the median scanner precision was below 0.05 mm, with statistically significant but negligible differences between scanners. The agreement between the scanners was approximately 0.06 mm. When single-tooth superimpositions were used to assess the precision of adjacent alveolar soft-tissue surfaces, the median error was 0.028 mm, and there was higher agreement between the scanners. The in vivo reliability of the intraoral scanners in the alveolar surface area was high overall. Single-tooth superimpositions should be preferred for the optimal assessment of neighboring alveolar surface areas relative to the dentition.

Soft tissue thickness evaluation in screw-retained crowns by the biologically oriented preparation technique (BOPT)

Background

Intraoral scanner evaluation (3Shape, TRIOS®) of soft tissue thickness around convergent collar implants and shoulderless abutments.

Material and Methods

Ambispective longitudinal analytical study with a sample size of 26 implants in 17 patients treated in a private dental clinic. Pacients were divided into two groups: Prama Implants or group 1 (n=19) and Shelta implants combined with XA abutment or group 2 (n=7). Thickness changes after one- and two-year follow-up were analyzed.

Results

In group 1 baseline mean thickness was 6.53 mm (±1.06) and follow-up mean thickness was 8.06 mm (±0.98), in group 2 initial mean thickness was 7.66 mm (±1.09) and follow-up mean thickness was of 8.42 mm (±1.03).

Conclusions

Biologically guided crowns design seems to significantly increase the soft tissue volumen around convergent morphology implants. Key words:Biologic width, peri-implant soft tissue, marginal bone loss, transmucosal implant, convergent collar, BOPT (biological oriented preparation technique), BOPT abutment, soft tissue stability, intraoral scanner.

Early soft tissue changes following implant placement with or without soft tissue augmentation using a xenogeneic cross-link collagen scaffold: A volumetric comparative study

OBJECTIVE

Soft tissue augmentation (STA) at implant sites has the potential of improving peri-implant health, esthetics, and marginal bone level stability. The present study aimed at evaluating the volumetric changes occurring following implant placement in sites that received STA compared to non-augmented sites.

METHODS

A total of 26 subjects received a dental implant in a posterior edentulous site. Simultaneous STA with a xenogeneic cross-linked collagen scaffold was performed for the first 13 patients, while the remaining subjects served as the negative control. An intraoral optical scanner was used at baseline and at 12 weeks to generate digital models.

RESULTS

The mean volume (Vol) gain of the test group was 38.43 mm³ , while a mean Vol of -16.82 mm³ was observed for the control group (p < 0.05). The mean thickness of the reconstructed volume (ΔD) was 0.61 and -0.24 mm, for the test and control group, respectively (p < 0.05). Higher linear dimensional changes were observed for the test group (p < 0.05), while no significant differences were observed in terms of keratinized mucosa width and pocket depth changes between the two groups.

CONCLUSIONS

Simultaneous STA with xenogeneic collagen scaffold obtained statistically significant higher volumetric outcomes compared to the non-augmented group.

CLINICAL SIGNIFICANCE

STA at the time of implant placement using a xenogeneic cross-linked collagen scaffold can prevent remodeling of the ridge during the first 12 weeks, as compared to non-grafted implant sites.

Prevalence and risk indicators of midfacial peri-implant soft tissue dehiscence at single site in the esthetic zone: A cross-sectional clinical and ultrasonographic study

BACKGROUND

Esthetic complications of dental implants in the esthetic zone can have a major negative impact on patients' quality of life and perception of implant therapy. The aim of the present study was to evaluate the prevalence of peri-implant soft tissue dehiscence (PSTD) and the clinical and ultrasonographic risk indicators for this condition.

METHODS

Subjects with one or more healthy single dental implants in the esthetic area were identified and recruited. Clinical and ultrasonographic measurements, including PSTD class and subclass, pocket depth, keratinized mucosa width (KMW), mucosal thickness (MT) at 1 mm and 3 mm, buccal bone distance (BBD) and buccal bone thickness, were evaluated in healthy implants and implants with PSTD.

RESULTS

153 subjects with a total of 176 dental implants were included. The prevalence of PSTD was 54.2% and 56.8% on a patient and implant level, respectively. The most frequent type of PSTD was the one characterized by having both an implant-supported crown longer than the clinical crown of the homologous tooth and a visible abutment/implant fixture exposed to the oral cavity. The multi-variate analysis showed that the presence of an adjacent implant, a longer time of the implant in function, limited MT, reduced KMW and increased BBD were significantly associated with the presence of a PSTD.

CONCLUSIONS

PSTDs are common findings in the esthetic region. Several risk indicators for this condition, such as presence of an adjacent implant, increased time in function of the implant, higher BBD, lower KMW and MT were identified. This article is protected by copyright. All rights reserved.

Soft tissue metric parameters, methods and aesthetic indices in implant dentistry: A critical review

OBJECTIVES

The primary objective was to provide an overview of soft tissue metric parameters, methods, and aesthetic indices in implant dentistry. The secondary objective was to describe reliability and validity of aesthetic indices.

MATERIALS AND METHODS

Two independent reviewers conducted an electronic literature search in Pubmed, Web of Science, Embase, and Cochrane databases up to October 2020 to identify studies on soft tissue metric parameters, methods, and aesthetic indices. Aesthetic indices were evaluated in terms of reliability and validity. Data extraction was performed by the same reviewers.

RESULTS

Five metric parameters (papilla height, linear changes in soft tissue level, color assessment, soft tissue thickness, and profilometric soft tissue changes) registered by means of several methods (intra-oral registrations, radiographic assessments, digital analyses, and ultrasonic assessments), and 15 aesthetic indices (Papilla Index (PI), ad hoc questions scored with Visual Analogue Scales, Pink Esthetic Score (PES), Implant Crown Aesthetic Index (ICAI), Implant Aesthetic Score (IAS), Rompen Index, Subjective Esthetic Score, White Esthetic Score, Copenhagen Index, Complex Esthetic Index, Californian Dental Association Index (CDAI), Peri-Implant, and Crown Index, Functional Implant Prosthodontic Score, Implant Restoration Esthetic Index (IREI), and Mucosal Scarring Index (MSI)) could be identified. With respect to metric parameters and methods, intra-oral registrations were least accurate whereas profilometric soft tissue changes on the basis of digital surface models were most accurate. Six aesthetic indices showed good inter-rater reliability (PI, PES, ICAI, CDAI, IREI, and MSI). Good validity could only be shown for two indices (PES and CEI). Given this and on the basis of ease of use and ease of interpretation, PES qualified best for clinical research on single implants. None of the indices fulfilled the quality criteria for clinical research on multiple implants.

CONCLUSION

Many soft tissue assessment methods with varying reliability and validity have been described and used, which hampers uniform reporting in implant dentistry. Clinical investigators are advised to measure linear and profilometric soft tissue changes using digital surface models, and to use a reliable and validated aesthetic index. Currently, PES qualifies best for aesthetic evaluation of single implants. An index is to be developed to assess the aesthetic outcome of rehabilitations on multiple implants.

A new digital evaluation protocol applied in a retrospective analysis of periodontal plastic surgery of gingival recessions

This research aimed to develop a new digital evaluation protocol to objectively quantify the volumetric changes of root coverage periodontal plastic surgery when combined with connective tissue graft. Consecutive patients with Cairo recession type 1 (RT1) or Cairo recession type 2 (RT2) were treated. Accurate study models obtained at baseline and follow-ups were optically scanned. Healing dynamics were measured by calculating volume differences between time points. Nineteen patients were treated between December 2014 and January 2019. At 3-month follow-up, root coverage was 95.6% (± 14.5%) with tunnel and connective tissue graft (TUN + CTG) technique, and 88.9% (± 20.5%) with the vestibular incision subperiosteal tunnel access and connective tissue graft (VISTA + CTG) technique. Recession decreased 1.33 (± 0.86) mm and 1.42 (± 0.92) mm, respectively (p = 0.337). At 6-month follow-up, root coverage was 96.5% (± 10.4%) with the TUN + CTG and 93.9% (± 10.3%) with the VISTA + CTG. Recession decreased 1.35 (± 0.85) mm and 1.45 (± 0.82) mm, respectively (p = 0.455). Complete root coverage was achieved in 86.7% (± 0.4%) with TUN + CTG and 70.6% (± 0.5%) with VISTA + CTG. No statistically significant differences were found between techniques. The digital protocol presented proved to be a non-invasive technique for accurate measurements of clinical outcomes. Both techniques reduce gingival recessions, with no statistically significant differences.

Effect of free gingival graft before implant placement on peri-implant health and soft tissue changes: a randomized controlled trial

BACKGROUND

To evaluate the clinical outcome and changes in posterior buccal soft tissue following implant restoration in groups with and without a free gingival graft (FGG) before implant placement.

METHODS

Twenty-six individuals who required implant restoration and displayed lack of keratinized mucosa (KM) were recruited and assigned to the FGG group (with FGG before implant placement) or Control group (without FGG before implant placement) randomly. A screw-retained conventional implant restoration was performed for each patient. Peri-implant soft tissue was captured by an intraoral scanner and analyzed by an image processing software. Clinical parameters (plaque index, gingival index, probing depth, and bleeding on probing) were assessed at baseline and 1, 3, 6, and 12 months. Buccal soft tissue changes (mucosal margin, soft tissue thickness, and width of keratinized mucosa) on the buccal side of implant site were assessed at 1, 3, 6, and 12 months. Two-way ANOVA and Bonferroni test were used to analyze significant difference between groups at each time point (α = 0.05).

RESULTS

The clinical parameters were lower in the FGG group than that in the Control group, although there were no significant differences between the two groups (P > 0.05). Peri-implant soft tissue collapsed and the changes (mucosal margin and soft tissue thickness) were significantly greater in the Control group than the FGG group (P < 0.05). Width of KM was larger in the FGG group than the Control group, although there was no significant difference between the two groups (P > 0.05).

CONCLUSIONS

Minimal peri-implant soft tissue changes occurred in two groups. Performing FGG before implant placement is a viable procedure to maintain peri-implant soft tissue but might not affect peri-implant health during 12 months follow-up. However, small sample size must be considered. Trial registration This study was retrospectively registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR2000037954; Date of registration: 6 September 2020).

Assessment of reference areas for superimposition of serial 3D models of patients with advanced periodontitis for volumetric soft tissue evaluation

AIM

This study aimed to determine the optimal reference area for superimposition of serial 3D dental models of patients with advanced periodontitis.

MATERIALS AND METHODS

Ten pre- and post-periodontal treatment 3D models (median time lapse: 13.1 months) of patients with advanced periodontitis were acquired by intraoral scanning. Superimposition was performed with the iterative closest point algorithm using four reference areas: (A) all stable teeth, (B) all teeth, (C) third palatal rugae and (D) the whole model. The superimposition accuracy was evaluated at two stable evaluation regions using the mean absolute distance and evaluated with two-way ANOVA and post-hoc multivariate model. The intra- and inter-operator reproducibility was calculated by intraclass correlation coefficient (ICC).

RESULTS

Superimposition accuracy evaluated at stable tooth evaluation region were 71 ± 29 μm, 73 ± 21 μm, 127 ± 52 μm and 113 ± 53 μm for areas A, B, C and D, respectively. All reference areas showed similarly high ICC values >0.990, except for reference area C showing ICC of 0.821 (intra-operator) and 0.767 (inter-operator) for tooth evaluation area.

CONCLUSIONS

Area A and B provide the highest accuracy for superimposition of serial 3D dental models acquired by intraoral scanning of patients with advanced periodontitis.