The etiology of hard- and soft-tissue deficiencies at dental implants: A narrative review

Correction of Peri-Implant Soft Tissue Fenestration With Bony Dehiscence Associated With Intrabony Defect: A 2-Year Case Report

Soft and hard tissue deficiencies around dental implants which can potentially compromise implant survival are commonly encountered. Complicated interventions are often required to address and resolve combinations of soft and hard tissue defects. This case report describes the management of peri-implant soft tissue fenestration accompanied by bony dehiscence associated with intrabony defect through soft tissue modification. A 51-year-old female was referred to the Periodontics and Oral Medicine Clinic with labial soft tissue fenestration at the maxillary left canine implant-supported crown. The patient complained of discomfort and malodor at the implant site. The implant showed mucosal fenestration and 6 mm probing depth (PD) with profuse bleeding at the distolabial site without mobility. A cone beam computed tomography (CBCT) demonstrated labial bony dehiscence associated with a 5.56-mm intrabony defect at mesial and distal surfaces. The implant was diagnosed as peri-implantitis with soft tissue deficiency. The treatment comprised oral hygiene instruction, debridement of the implant and all natural teeth, and mucogingival surgery with free connective tissue graft by the envelope technique. Two weeks after debridement, the mucosal margin of the implant disappeared, presenting soft tissue dehiscence of 4 × 4 mm. Mucogingival surgery was performed 3 weeks later. A 2-year follow-up revealed a stable mucosal margin with PD ranged 2-4 mm. In conclusion, modification of the soft tissue thickness around the implant together with excellent plaque control by the patient successfully maintained peri-implant health.

Influencing Factors Regarding the Severity of Peri-Implantitis and Peri-Implant Mucositis

The scientific literature is increasingly focused on peri-implant mucositis and peri-implantitis, which are biological outcomes of dental implant treatment.

BACKGROUND/OBJECTIVES

The present study aimed to evaluate the two most critical complications of dental implantation, peri-implant mucositis and peri-implantitis, through the prism of different influencing factors.

METHODS

We followed 40 patients, with a total number of 92 dental implants, divided into three age groups: under 35 years, between 35 and 55 years, and older than 55 years. Patients were also divided into groups according to the time since implant placement: 1-3 years, 4-7 years, and more than 7 years. The patients were examined, and periodontal pocket depth, peri-implant pocket depth, Löe-Silness gingival index, mucosal thickness, and keratinized mucosal width were recorded; bone resorption was measured on radiographs using a 2D image analysis method; and a questionnaire was also conducted.

RESULTS

Bone resorption was highest in the 35-55 age group (3.09 ± 0.04 mm) and for implants placed 4-7 years ago (3.39 ± 0.12 mm). Females had a mean bone resorption of 3.4 ± 0.15 mm and males of 2.45 ± 0.07 mm. Statistically, there was a significant difference only in the Löe-Silness index: the 35-55 age group had the highest values (p = 0.04).

CONCLUSIONS

There were no statistically significant differences between the time since implant placement and the degree of bone resorption, nor between sexes. Peri-implant inflammation may occur at any age, regardless of the lifetime of the implants.

Accuracy of dental implant placement using different dynamic navigation and robotic systems: an in vitro study

Computer-aided implant surgery has undergone continuous development in recent years. In this study, active and passive systems of dynamic navigation were divided into active dynamic navigation system group and passive dynamic navigation system group (ADG and PDG), respectively. Active, passive and semi-active implant robots were divided into active robot group, passive robot group and semi-active robot group (ARG, PRG and SRG), respectively. Each group placed two implants (FDI tooth positions 31 and 36) in a model 12 times. The accuracy of 216 implants in 108 models were analysed. The coronal deviations of ADG, PDG, ARG, PRG and SRG were 0.85 ± 0.17 mm, 1.05 ± 0.42 mm, 0.29 ± 0.15 mm, 0.40 ± 0.16 mm and 0.33 ± 0.14 mm, respectively. The apical deviations of the five groups were 1.11 ± 0.23 mm, 1.07 ± 0.38 mm, 0.29 ± 0.15 mm, 0.50 ± 0.19 mm and 0.36 ± 0.16 mm, respectively. The axial deviations of the five groups were 1.78 ± 0.73°, 1.99 ± 1.20°, 0.61 ± 0.25°, 1.04 ± 0.37° and 0.42 ± 0.18°, respectively. The coronal, apical and axial deviations of ADG were higher than those of ARG, PRG and SRG (all P < 0.001). Similarly, the coronal, apical and axial deviations of PDG were higher than those of ARG, PRG, and SRG (all P < 0.001). Dynamic and robotic computer-aided implant surgery may show good implant accuracy in vitro. However, the accuracy and stability of implant robots are higher than those of dynamic navigation systems.

In vivo comparison of customized zirconia barriers in guided bone regeneration: An experimental study

Objective

This study aims to evaluate the effects of customized zirconia barrier membranes produced for guided bone regeneration (GBR) approaches on bone healing researched with histological and histomorphometric methods.

Methods

The digital modeling was used to create zirconia barrier membranes suitable for the defect on the tibia bone. The membranes were designed using a 3D software system and transferred to the CAD/CAM software system in stl. Afterward, zirconia discs (1400 Mpa) (Aconia BSM- D98 × 16, HT+, Germany) were milled and sintered. Titanium mesh, titanium reinforced d-PTFE, and zirconia barrier membranes were used to cover the defects. As a control group, one defect was left empty. 3 and 6 weeks of the healing term, preparates were obtained from each group after animals were sacrificed. New bone formation, amount of the remaining grafts and tissue response parameters were analyzed histomorphometrically and histologically.

Results

The highest percentage of newly formed bone in the early period was observed in the titanium mesh membrane group (26.39 ± 5.38); In the late period, this rate was highest in the zirconia group (64.42 ± 9.95). However, no statistically significant difference was found in both periods between the groups. The amount of residual graft progressed at a low level in both periods without any difference in the other groups except the control group. In the 3rd and 6th weeks, the amount of new bone formation was the lowest in the control group. No foreign body reaction or necrosis was observed in any of the defects.

Conclusion

With the limitation of the study, it has been concluded that effective results can be obtained with customized zirconia barrier membranes in GBR procedures.

Coverage stability of peri-implant soft tissue dehiscence: A systematic review and meta-analysis

OBJECTIVE

The occurrence of peri-implant soft tissue dehiscence, especially in the esthetic zone, can be challenging. This study sought to investigate how the passage of time affects the outcomes of treatment for peri-implant soft tissue dehiscence coverage.

MATERIALS AND METHODS

A literature search was performed up to April 2023 via PubMed, Scopus, and Web of Science to retrieve studies reporting the data on peri-implant soft tissue dehiscence of at least 2-time points (baseline and follow-up). Clinical trials with a minimum of 5 participants, reporting at least 1 primary outcome, and with a minimum follow-up of 3 months were included. The primary outcomes were the changes in dehiscence depth, complete coverage, and mean coverage at different time points.

RESULTS

Seven studies with 112 participants and 119 implants were included. Dehiscence depth increased insignificantly between 3 to 6 months. Although the dehiscence depth increased from 6 to 12 months in the tunnel group, it decreased in the coronally advanced group, and a slight decrease was observed from 12 to 72 months. Soft tissue thickness was the predictor for soft tissue margin stability. However, no significant relationship was found between the baseline dehiscence depth and complete coverage.

CONCLUSIONS

Within the limitations of this study, it seems prudent to wait at least 6 months to achieve a stable soft tissue margin.

CLINICAL SIGNIFICANCE

The occurrence of peri-implant soft tissue dehiscence, especially in the esthetic zone, can be a challenging complication. It is important not only to achieve coverage but also to ensure that the treatment results remain stable in the long term, in order to satisfy both patients and clinicians. A reasonable approach would be to wait for at least 6 months to achieve a stable soft tissue margin.

Clinical protocol selection for alveolar ridge augmentation at sites exhibiting slight, moderate, and severe horizontal ridge deficiencies

FOCUSED CLINICAL QUESTION

What factors identify the optimal bone augmentation techniques for managing slight, moderate, and severe horizontal alveolar ridge deficiency (ARD) at dental implant sites?

SUMMARY

Horizontal ARD is a concern at a high proportion of sites receiving dental implants, and clinicians have developed a variety of surgical procedures to address such defects. In a particular case, selection of the optimal treatment may depend predominantly on defect severity, location (anterior versus posterior), and configuration (contained versus noncontained). This report provides a framework for selecting an augmentation method when presented with a slight, moderate, or severe horizontal ARD at a site requiring dental implant placement.

CONCLUSION

Multiple treatment options are available for planned implant sites exhibiting horizontal ARD; severe posterior and slight anterior defects intuitively call for different approaches. Although rigid guidelines for selecting the optimal augmentation method do not exist, some techniques are poorly suited for esthetically demanding sites. A framework considering defect severity, location, and configuration may help guide clinical decisions on this topic.

Is Laser Therapy an Adjuvant in the Treatment of Peri-Implant Mucositis? A Randomized Clinical Trial

(1) Background: Early diagnosis and treatment of peri-implant mucositis may reduce inflammatory markers and halt the progression of the condition to peri-implantitis. Adjunctive laser treatment may have therapeutic benefits that are not yet well known. The aim of this study was to determine the advantages and limitations of laser therapy as an adjuvant in the treatment of peri-implant mucositis. (2) Methods: A total of 42 patients with at least 2 implants situated in different hemiarches were included in this study and divided into two groups: G1 (received laser therapy) and G2 (no laser therapy). Periodontal health status indices were recorded at the initial moment (T0), and all patients underwent non-surgical debridement therapy accompanied by oral hygiene training. In patients from group G1, one implant site received adjuvant laser therapy (subgroup IL), and the other one did not receive active laser light (IC). The plaque index (PI), probing pocket depth (PPD), and bleeding on probing (BOP) values recorded after 3 months (T1) and 6 months (T2) were analyzed and compared with those at T0. (3) Results: PI values considerably reduced at moment T1 and T2 for both G1 and G2 (p = 0.0031). PPD was also reduced, but the difference between the groups and the three recording moments was not statistically significant. Statistically significant differences were found when comparing the BOP values between G1 IL and G1 IC for T0/T1 (p = 0.0182) and T1/T2 (p < 0.0001), but there was no significant difference between G2 and G1 IL or G1 IC. (4) Conclusions: Laser therapy as an adjunct to conventional treatment of peri-implant mucositis leads to a statistically significant reduction in bleeding on probing at 3-month and 6-month re-evaluations. Moreover, it leads to an evident reduction in probing depth but with no statistical significance. These results should be interpreted with caution, and more in-depth research should be performed to create a complete laser therapy protocol for peri-implant mucositis.

Two-Step Progressive Transcrestal Sinus Augmentation Using a 4.5 mm Unloaded Implant as a "Temporary Implant" in Highly Atrophic Ridge: Case Report

Severe atrophic posterior maxillary ridge (residual bone height < 3 mm) could be a challenging situation to place dental implants. Several treatment options have been proposed, but some of them may require advanced surgical skills to achieve best results. In this article, we present a novel and easier technique to allow implant placing in localized areas of severe atrophy. In a first step, a 4.5-length extra-short (unloaded) implant is placed after a transcrestal maxillary sinus floor augmentation (MSFA). After the gained apical bone consolidation, this "temporary implant" is atraumatically removed and a longer and wider definitive implant is placed to support the definitive single restoration. The case of a 45-year-old female treated with this approach is also presented. The patient suffered a severe resorption in the upper right molar area after a tooth extraction. Four months after the "temporary implant" placement and MSFA grafting with plasma rich in growth factors and autologous bone, 3 mm of dense apical bone gain could be observed. In a second surgical time, the 4.5 mm-length "temporary implant" was removed, and a 5.5 mm-length "definitive implant" was placed. This second implant was placed in a denser type 1 (1,000 Hounsfield Unit) new formed apical bone. Four months later, the implant was loaded with a screw-retained crown over a transepithelial (intermediate abutment). After 1-year follow-up, the implant was in health and no mechanical or biological complications were noticed. The satisfactory results of this case encourage the realization of new studies to elucidate its reproducibility.

In vivo trueness and precision of full-arch implant scans using intraoral scanners with three different acquisition protocols

OBJECTIVES

To evaluate an in situ reference acquisition method for implant positions in complete edentulous maxillae using an industrial scanner and allowing for in vivo trueness analysis of the restorative workflow. To assess in vivo trueness and precision of intraoral scanners (IOS) using different acquisition protocols. Furthermore, to compare IOS trueness with impression-based models and implant-supported fixed dentures (IFD) in a parallel study on the same cohort using the same in situ reference scan.

METHODS

Six scan-bodies mounted to maxillary implants in five subjects were reference scanned (REF) using an industrial scanner. Subjects were scanned with IOS three times using three different protocols: control (CT), dental floss assisted (DF), and acrylic splint (SP). CAD-files of scan-bodies with inter-aligned analogues were geometry-aligned to REF, and SP. Scan-bodies were aligned to CT and DF in proprietary dental laboratory software and exported with analogue positions. Resulting six CAD-analogues per scan were Globally Aligned using a consistent geometry-based alignment. Deviations were computed after a Reference Point System Alignment at the implant/prosthetic platform for Cartesian axes with a linear Resultant.

RESULTS

Resultant trueness was CT: 41±11 µm, DF: 49±22 µm, SP: 55±8 µm. Resultant precision was CT: 48±7 µm, DF: 50±7 µm, SP: 45±6 µm.

CONCLUSIONS

This method is applicable for assessing trueness of maxillary full-arch implant scans in vivo. The CT protocol was most accurate. CT trueness showed no difference to digitised impression-based models in parallel study. CT was more accurate than IFD in a parallel study. CT displayed similar numerical trueness as existing in vitro studies.

CLINICAL SIGNIFICANCE

Using IOS to acquire full-arch implant scans is controversial. The modified protocol in this pilot shows promising results in the maxilla where great care was taken to manage non-attached tissues when a modified scanning pattern was used. However, other IOS may show varying results in vivo. A completed scan does not necessarily equate to an accurate scan.

Impact of peri-implant soft tissue characteristics on health and esthetics

OBJECTIVE

To review the impact of key peri-implant soft tissue characteristics on health and esthetics.

MAIN CONSIDERATIONS

The keratinized mucosa width (KMW), the mucosal thickness (MT), and the supracrestal tissue height (STH) are essential components of the peri-implant soft tissue phenotype. An inadequate KMW (<2 mm) has been associated with local discomfort upon oral hygiene performance and increased risk for the onset of peri-implant diseases. A minimum buccal MT (≥2 mm) is generally required to prevent esthetic issues related to the effect of transmucosal prosthetic elements on the color of the mucosa and can also contribute to long-term mucosal stability. STH is directly related to marginal bone remodeling patterns during the early healing process that follows the connection of transmucosal prosthetic components. Short STH, generally defined as <3 mm, has been consistently associated with marginal bone loss resulting from the physiologic establishment of the mucosal seal. Insufficient STH may also derive into the fabrication of unfavorable transmucosal prosthetic contours, which frequently results in unpleasing esthetic outcomes and predisposes to submarginal biofilm accumulation. Peri-implant soft tissue dehiscences (PISTDs) are a type of peri-implant deformity that are associated with esthetic issues and often occur in sites presenting KMW, MT, and/or STH deficiencies. PISTDs should be correctly diagnosed and treated accordingly, usually by means of multidisciplinary therapy.

CONCLUSION

Understanding the impact of different dimensional and morphologic features of the peri-implant mucosa on health and esthetic outcomes is fundamental to make appropriate clinical decisions in the context of tooth replacement therapy with implant-supported prostheses.

Polycaprolactone versus collagen membrane and 1‐year clinical outcomes: A randomized controlled trial

BACKGROUND

Polycaprolactone (PCL) is a synthetic aliphatic polyester widely used in biomedical applications with biodegradability in the body and promotes cell proliferation and differentiation. A newly developed bilayered PCL membrane was developed for possibly being used as a membrane in guided bone regeneration (GBR).

PURPOSE

To compare the clinical efficacy between a newly developed bilayered PCL membrane with a Cytoplast™ RTM collagen membrane for GBR with simultaneous implant placement.

MATERIALS AND METHODS

Twenty-four patients were randomized to PCL or RTM group, and a total of 24 dental implants were placed. Primary outcomes were patient mean buccal bone thickness (BBT) immediately postimplantation and at 6 months using cone-beam CT and soft tissue surface dimensional changes (STC) at crown insertion, 6 months, and 1 year after loading using intraoral scanner. Secondary outcomes included success rate, clinical parameters, healing index, implant stability, pink esthetic score, and marginal bone levels.

RESULTS

The percentage of reduced BBT at 6 months was 32.38%, 25.94%, and 23.96% in the test group and 34.42%, 14.75%, and 6.34% in the control group at the corresponding levels. The mean difference of changed BBT associated with PCL membrane, when compared to collagen membrane, at 6 months was -0.02 ± 0.18 mm (95% confidence interval [CI]: -0.40 to 0.35), 0.29 ± 0.28 mm (95% CI: -0.29 to 0.87), and 0.62 ± 0.38 mm (95% CI: -0.17 to 1.42) at 0, 2, and 4 mm from implant shoulder. Minimal loss of STC was observed in both groups up to 1 year of loading. The mean difference loss of surface dimensional change associated with PCL membrane, when compared to collagen membrane, at 1 year of loading was 0.31 ± 0.19 mm (95% CI: -0.07 to 0.70), 0.22 ± 0.26 mm (95% CI: -0.33 to 0.76), and 0.17 ± 0.30 mm (95% CI: -0.45 to 0.78) at 0, 2, and 4 mm from implant shoulder. None of these differences were statistically significant (unpaired t-test, degrees of freedom [df] = 22; p > 0.05).

CONCLUSION

Within the limits of this trial, both barrier membranes resulted in comparable outcomes for GBR with implant placement after 1 year in function. Further research is necessary with a larger sample size.

Clinical applications of mucogingival therapies utilizing adjunctive autologous blood products

BACKGROUND

Mucogingival deformities are prevalent oral conditions and can result in esthetic compromise, dentinal hypersensitivity, and an increase in radicular caries rates. Mucogingival treatments address thin periodontal phenotype and/or gingival recession defects. Although many of these grafting procedures are predictable in improving soft-tissue quality and quantity around teeth and dental implants, patients often complain of discomfort at both the donor and recipient sites. Free gingival grafts and coronally advanced flaps alone or in combination with subepithelial connective tissue graft and/or acellular dermal matrix are among the most common surgical procedures employed to achieve root coverage and enhance periodontal phenotype. Autologous blood products (ABPs) contain platelets, growth factors, leukocytes, and stem cells that contribute to cell mitosis, collagen production, and angiogenesis, leading to the healing and regeneration of hard and soft tissue. Evaluation of the adjunctive role of ABPs in mucogingival surgery and their impacts on clinical and patient-centered data is critical to achieve optimal patient-reported outcome measures based upon the current scientific evidence.

METHODS

We present exemplar cases in which adjunctive ABPs were utilized in mucogingival treatment to enhance treatment outcomes.

RESULTS

No adverse events were noted. Satisfactory treatment outcomes were achieved in patients with local and/or systemic compromise when mucogingival therapies were used in combination with ABPs.

CONCLUSIONS

Adjunctive use of ABPs may enhance outcomes of mucogingival therapy. Utilization of adjunctive ABPs may be particularly advantageous in situations where the predictability of clinical and esthetic outcomes is limited due to anatomical and/or patient factors.

Impact of Smoking Habit on Peri-Implant Indicators following Different Therapies: A Systematic Review

Peri-implant disease and its treatment is becoming a major concern for clinicians as the number of implants placed each year is rising. Smoking is a common habit, and it is associated with an increased risk of developing peri-implant disease. The role of smoking in the response to peri-implant treatment has never been investigated. Searches were conducted in electronic databases to screen articles published until August 2021. The included studies had at least two groups of patients: peri-implant disease only or peri-implant disease and smoking status. Outcomes of interest included plaque index (PI), probing depth (PD), bleeding on probing (BoP), radiographic crestal bone loss (CBL), and analysis of peri-implant sulcular fluid. Seven hundred and forty-nine articles were found in the databases, only 71 articles potentially qualified. A total of seven studies with a minimum follow-up of six months were included. There is no homogeneity in the diagnosis, smoker definition and treatment proposed. All surgical and non-surgical treatment have statistically significantly different outcomes in smokers and nonsmokers. Recognizing this study’s limitations, we conclude that smoking might play a significant role on the outcome of peri-implant disease treatment. None of the proposed treatments appear to be significantly more effective.

Implant site development requirements in an advanced dental education program: A series of 290 implants

PURPOSE

Our purpose was to assess the frequency and impact of various site development procedures provided before, during, and after implant placement in an advanced dental education program.

METHODS

We evaluated all implant cases completed by two residents in each of three consecutive periodontics residency classes. Dependent variables included implant failure, complication occurrence, presence of radiographic bone loss, and need for tissue augmentation. We analyzed these outcomes against a panel of explanatory covariates.

RESULTS

Our study sample involved 370 site development procedures at 290 implant sites in 160 patients. Three factors exhibited statistically significant associations with need for tissue augmentation: alveolar ridge preservation (ARP) (odds ratio [OR] 0.28; 95% confidence interval [CI] 0.13, 0.57), immediate implant placement (IIP) (OR 0.21; 95% CI 0.10, 0.47), and implant submergence (OR 8.3; 95% CI 4.5, 15.3). Four factors predicted treatment complications: ARP (OR 6.1; 95% CI 1.3, 29.1), IIP (OR 6.1; 95% CI 1.06, 35.3), implant submergence (OR 5.3; 95% CI 1.1, 24.9), and mandibular arch (OR 31.3; 95% CI 1.9, 500). Anterior sites (OR 2.7; 95% CI 1.3, 5.8) were more likely to receive IIP.

CONCLUSIONS

In the evaluated sample, implant placement at a site exhibiting a favorable volume of native bone was rare. Seventy-eight percent of sites received hard tissue grafting during the treatment phase. The use of ARP or IIP at tooth extraction reduced subsequent tissue augmentation requirements. Education and training in ARP and other site development procedures may enhance the clinical practice and treatment outcomes of implant surgeons.

Three interfaces of the dental implant system and their clinical effects on hard and soft tissues

Anatomically, the human tooth has structures both embedded within and forming part of the exterior surface of the human body. When a tooth is lost, it is often replaced by a dental implant, to facilitate the chewing of food and for esthetic purposes. For successful substitution of the lost tooth, hard tissue should be integrated into the implant surface. The microtopography and chemistry of the implant surface have been explored with the aim of enhancing osseointegration. Additionally, clinical implant success is dependent on ensuring that a barrier, comprising strong gingival attachment to an abutment, does not allow the infiltration of oral bacteria into the bone-integrated surface. Epithelial and connective tissue cells respond to the abutment surface, depending on its surface characteristics and the materials from which it is made. In particular, the biomechanics of the implant-abutment connection structure (i.e., the biomechanics of the interface between implant and abutment surfaces, and the screw mechanics of the implant-abutment assembly) are critical for both the soft tissue seal and hard tissue integration. Herein, we discuss the clinical importance of these three interfaces: bone-implant, gingiva-abutment, and implant-abutment.

Comparison of Classifications and Indexes for Extraction Socket and Implant Supported Restoration in the Aesthetic Zone: a Systematic Review

OBJECTIVES

The primary objective of the present systematic review is to test the hypothesis - the revision of the complexity of the extraction sockets morphology classifications will reveal the most important parameters for implant aesthetic and functional success in case of immediate dental implant placement in aesthetic zone. The secondary objective is to revise the most important parameters of aesthetic indexes created for implant-supported restoration in aesthetic zone.

MATERIAL AND METHODS

MEDLINE (PubMed) and Cochrane Library search in combination with hand-search of relevant journals was conducted including human studies published in English between 1 January 2005 and 1 February 2022. After evaluation of the titles and abstracts in accordance with the PRISMA guidelines, risk-of-bias assessment was evaluated and data was extracted from the full papers.

RESULTS

Electronic and hand searching resulted in 477 entries. Five systematic reviews, research syntheses and 7 prospective studies met the inclusion criteria and were included in the final data synthesis. Selected articles reported the different classifications complexity of the extraction sockets morphology and aesthetic indexes for implant supported restoration in aesthetic zone.

CONCLUSIONS

The most important parameters for implant aesthetics and functional success, incorporated in classifications of extraction sockets are facial soft tissue level and quality, gingival biotype, keratinized gingival, mesial and distal papillae appearance, buccal bone level and thickness, labial and buccal bone plates damage and bone lesions. The most important aesthetic indexes parameters are soft tissue contour position, including colour and texture, interdental papilla, mesial and distal interproximal bone height, gingival biotype.

Free-Hand versus Surgical Guide Implant Placement

One of the most key areas of dentistry is dental implant surgery. The use of digital equipment and software in dentistry has developed considerably in recent years compared to other fields of medicine. Since examining the advantages and disadvantages of each approach, along with case studies, can help physicians make informed decisions, this review study aims to raise the awareness of dentists to make easier decisions about using guided or free-hand surgery. When planning for a dental implant, one of the most challenging questions that doctors face is which method to use (guided surgery or free-hand). Choosing the right method, such as other clinical considerations, will depend on the individual circumstances of each patient and the preference of the treating physician. Free-hand surgery is a cost-effective method in which the flap is reflected, and, according to the doctor's diagnostic information, an implant is placed, which in many cases is a useful method. Guided surgery has the highest level of accuracy and control, in which osteotomy is designed and printed through a digital surgery guide, and depending on the complexity of the case and the patient's anatomy, it has a higher level of value than free surgery. The surgical guide helps the surgeon make the implant surgery more accurate, safer, simpler, at a lower cost, and in less time. In fact, there are patterns that convey information about the position of the tooth to the dentist before the implant is placed.

Dental implants at sites of focal high and mixed density osseous lesions: Clinical practice guidelines

FOCUSED CLINICAL QUESTION

Under what circumstances may a clinician consider dental implant placement at a site exhibiting a focal high or mixed density (HMD) osseous lesion radiologically?

SUMMARY

Some conditions and pathologic entities exhibiting high and mixed density radiological appearance pose low risk for dental implant failure or complications following implant surgery. However, other lesions represent contraindications to implant placement, and implant surgery at such sites can result in severe morbidity.

CONCLUSION

Potential implant sites exhibiting focal HMD osseous lesions/conditions present varying levels of risk. In most cases, optimal management will include advanced imaging of the site, multidisciplinary consultations, and detailed informed consent to assure full understanding of procedural risks, benefits, and complications. Currently, clinical recommendations rely on case reports, opinion, and usual practice (level 3 evidence). The strength of each recommendation provided in this report is categorized as level C.

Ultrasonographic evaluation of edentulous crestal bone topography: A proof-of-principle retrospective study

OBJECTIVE

Edentulous crestal bone ridge assessment, an essential task for planning of implant and bone regenerative procedures, is performed through radiographs. Ultrasonography, providing point of care and cross-sectional images without radiation, could be an adjunct for this purpose. The aim was to investigate the feasibility of ultrasound (US) in assessing bone ridge width (BRW) and crestal bone surface quality (CBSQ) compared with cone beam computed tomography (CBCT).

STUDY DESIGN

Records of patients who were planned for implant placement in at least 1 healed edentulous ridge space with available CBCT and US images were included. The BRWs at 1, 2, and 3 mm from the crest were measured and compared. The CBSQ agreement evaluated using a 3-tier grading system was calculated.

RESULTS

A total of 45 sites were included. The mean correlation of BRW was 0.97. The mean BRW differences ranged from 0.048 mm (95% confidence interval, -0.69 to 0.78 mm) at the 1-mm level to 0.18 mm (95% confidence interval, -0.92 to 1.3 mm) at the 3-mm level. There was a 91% agreement in CBSQ between the 2 methods.

CONCLUSIONS

Preliminary data with a limited clinical sample size suggested that US is feasible in evaluating crestal BRW and surface quality assessment compared with CBCT.

Interdisciplinary management of recession defects on maxillary single tooth implants: Diagnosis and treatment strategies

OBJECTIVE

One of the most common complications with dental implants placed in the smile zone is the development of mid-facial recession, creating an undesirable esthetic result. When deciding how to remediate these clinical scenarios, the question becomes whether it may be feasible to save the problematic implant or if it is more predictable to remove the implant and start all over again. However, patients may be invested emotionally, physically, and financially in the implant and remediation may be a viable option depending on the diagnosis of the specific issues at hand and multi-disciplinary clinical execution.

CLINICAL SIGNIFICANCE

What is crucial to understand in order to remediate these cases is answering four separate criteria: (1) is the implant in a restorable position, (2) is the implant healthy, (3) is the implant placed at an adequate depth, and (4) are components available to restore the implant.

CONCLUSIONS

Two different clinical reports are presented that demonstrate various treatment remedies when saving implants in the esthetic zone.

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.

Replacement of an existing maxillary anterior fixed dental prosthesis, redo another fixed dental prosthesis, or convert to implants

OBJECTIVE

The purpose of this article is to discuss the considerations that need to be evaluated when considering the replacement of an existing maxillary anterior fixed dental prosthesis (FDP) with another FDP, or when to consider converting to implants and individual crowns on the previous abutment teeth.

OVERVIEW

The need to replace unesthetic or failing maxillary anterior FDPs is something all restorative dentists will be faced with multiple times in their careers. Given the emphasis over the past few decades on utilizing implants for tooth replacement as opposed to a tooth supported FDP, the question becomes when is converting the existing FDP to implants and single crowns an appropriate choice, as opposed to redoing a new FDP. This article will focus on the risks of choosing to convert to an implant solution, and the risks of redoing the tooth supported FDP. Multiple systematic reviews on each approach will be used to aid in the decision process. The most significant risks for both approaches will be identified, and a chart of the key parameters to assess will be presented, along with their impact.

CONCLUSIONS

The statistical outcomes at 5 and 10 years of tooth supported FDPs, and Implant based restorations are very similar if certain clinical parameters are met, namely vital healthy abutment teeth for the FDP, and adequate bone and soft tissue for the implant-based restoration. If one abutment tooth is compromised the long-term prognosis drops significantly and converting to an implant-based restoration may be more predictable. Similarly, if adequate bone and soft tissue cannot be obtained through surgical augmentation procedures, using a connective tissue graft for the ridge, and redoing the FDP may obtain a more acceptable esthetic result.

CLINICAL SIGNIFICANCE

A significant number of maxillary anterior FDPs exist that will need replacement in the future. Given the desire of many dentists to utilize implants when possible, there can be a tendency to automatically treatment plan an implant-based approach for replacement of the existing FDP. Certainly, most clinicians would favor an implant-based tooth replacement rather than preparing unrestored teeth to place an FDP, but when an existing FDP exists, the teeth have already been prepared for full coverage in most instances. In addition, for most long term existing FDPs, there is a significant change in the vertical and horizontal dimension of the bone and soft tissue that can make getting an acceptable esthetic result with an implant challenging. This article provides a systematic approach to identifying when redoing the FDP may be preferable, or when converting to an implant-based approach is a better choice.

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.

Tilted versus axial implant distribution in the posterior edentulous maxilla: A CBCT analysis

OBJECTIVES

This study aimed to determine whether distally angulating an implant is a successful strategy to avoid the maxillary sinus and the need for bone augmentation, while increasing the anterior-posterior (A-P) implant distribution in the edentulous maxilla.

MATERIALS AND METHODS

In 115 patients with edentulous maxillae, virtual implant planning was performed utilizing cone-beam computer tomographs. Axial (8 mm length) and tilted (12 mm length) dental implants with 30-degree and 45-degree angulation were virtually positioned to avoid entering the maxillary sinus, while maximizing A-P distribution. Measurements were made between the tilted and axial implants to assess the change in A-P distribution of implants at the implant and abutment levels.

RESULTS

Forty-seven sites (20.4%) were not able to have either treatment modality with insufficient bone for implant placement. Axial implants were placed more distally than 45-degree and 30-degree tilted implants in 24% and 42% of sites, respectively. The average change in A-P spread measured at the implant level, for 30- and 45-degree tilted implants was -0.25 mm (95% CI -0.76, 0.26) and 1.9 mm (95% CI 1.4, 2.3), respectively. When measured from the center of each multi-unit abutment the average increase in A-P distances for tilted implants appears larger in the 30-degree and 45-degree groups by 0.97 mm and 1.74 mm, respectively compared to measurements at the implant level.

CONCLUSIONS

Angulating 12 mm implants provides a limited increase in A-P distribution of implants in edentulous rehabilitation in most situations. In certain patients, the use of 8mm axial implants may provide a greater A-P spread.

Is there any biomaterial substitute for peri-implant soft tissue phenotype modification? A network meta-analysis of the appraisal literature

Evidence shows that an increased width and thickness of the keratinized mucosa favours peri-implant health. The aim of this network meta-analysis was to compare the clinical effects of alternative biomaterials for peri-implant soft tissue phenotype modification (PSPM) in patients with dental implants when compared to autologous tissue grafts. An electronic search without language or date limitations was performed in four databases and the grey literature for articles published until November 2020. The eligibility criteria included randomized clinical trials (RCTs) evaluating the clinical outcomes of biomaterials for PSPM. A pairwise and network meta-analysis was conducted for each parameter to assess and compare the outcomes between the different treatment arms for the primary and secondary outcomes. A total of 11 RCTs were included in this review. The free gingival graft (FGG) showed the best clinical effect for increasing keratinized mucosa width (KMW). When compared in a network, the FGG demonstrated the best treatment ranking of probability results, followed by connective tissue graft (CTG), acellular dermal matrix (ADM), and xenogeneic collagen matrix (XCM). For the parameters 'mucosa thickness' and 'participant satisfaction with aesthetics', the results were CTG > ADM > XCM and XCM > ADM > CTG, respectively. Autogenous tissue grafts (FGG/CTG) demonstrate the best results in increasing KMW and mucosa thickness when compared to the other biomaterials.

Influence of zirconia implant surface topography on first bone implant contact within a prospective cohort study

BACKGROUND

Although 5-year clinical data exist for different zirconia implants, no analysis has yet been performed focusing on how the surface topography of the implant affects clinical parameters.

PURPOSE

To analyze the influence of zirconia implant topography on first bone implant contact (fBIC).

MATERIALS AND METHODS

In a prospective two-center cohort investigation 63 zirconia implants were evaluated at implant placement, prosthetic delivery, 1, 3, and 5 years. The distance (DIB) between implant shoulder and fBIC was measured at each time point in periapical radiographs at mesial and distal sites. Two-way ANOVA/Bonferroni was used to analyze the effects of time and center (α < 0.05).

RESULTS

Between the centers, the mean DIB varied significantly at implant placement (Freiburg [FR]: 1.4 ± 0.6 mm; Zurich [ZH]: 0.8 ± 0.5 mm). Thereafter, no statistically significant difference in DIB was observed, neither between centers nor between time points (prosthetic delivery: FR: 1.9 ± 0.6 mm, ZH: 1.7 ± 0.8 mm; 1 year: FR: 1.8 ± 0.6 mm, ZH: 1.6 ± 0.8 mm; 3 years: FR: 1.9 ± 0.8 mm, ZH: 1.7 ± 0.8 mm; 5 years: FR: 1.9 ± 0.8 mm, ZH 1.8 ± 0.6 mm). The overall mean DIB at prosthetic delivery to 5 years of both centers (1.8 ± 0.7 mm) is located within the transition zone between the smooth neck and the moderately rough intraosseous part (1.6-2.0 mm from the implant shoulder). However, individual DIB values are ranging from 0.1 to 4.2 mm overlapping the transition zone.

CONCLUSIONS

The standard deviation of the DIB indicates that the fBIC establishes on moderately rough and smooth surfaces. Consequently, soft tissue adapts to both topographies as well.

Vertical bone augmentation utilizing a titanium-reinforced PTFE mesh: A multi-variate analysis of influencing factors

OBJECTIVE

To clinically evaluate the use of a titanium-reinforced PTFE mesh for vertical bone augmentation (VBA) of deficient alveolar ridges.

MATERIALS AND METHODS

This case series documented consecutive patients treated for VBA with a newly developed PTFE mesh. VBA was performed in anterior and posterior, maxillary and mandibular arches using anorganic bovine bone combined with autogenous graft in a 1:1 ratio. Healing time from initial surgery to re-opening was recorded. Baseline vertical deficiency, absolute bone gain (gross height gained), and relative gain (percentage of defect fill with respect to the baseline deficiency) were registered.

RESULTS

Fifty-seven patients (65 defects) were included in the analysis. The mean baseline vertical deficiency was 5.5 ± 2.6 mm. The mean absolute bone gain was 5.2 ± 2.4 mm. A relative gain of 96.5 ± 13.9% was achieved. Overall, 89.2% of cases showed complete regeneration, which occurred in all sites with baseline deficiencies of <5 mm, in 95.6% of sites with 5-8 mm deficiencies, and in 89.4% of sites with >8 mm deficiencies. Each 1-mm addition to the baseline height deficiency increased the likelihood of incomplete bone regeneration by 2.5 times. Defect location had a statistically significant but a limited clinical impact on the bone height gained (<0.5 mm). Complications were observed in three cases (3%).

CONCLUSIONS

Vertical bone augmentation with titanium-reinforced PTFE mesh and a mixture of autologous bone and xenograft is a safe and predictable procedure. The extent of the baseline vertical deficiency influences the percentage of bone gained.

Removable denture is a risk indicator for peri-implantitis and facilitates expansion of specific periodontopathogens: a cross-sectional study

Background

The prevalence of peri-implantitis ranges between 7 and 38.4% depending on risk indicators such as smoking, diabetes mellitus, lack of periodontal maintenance program, and history or presence of periodontitis. Currently, the possible effect of the type of superstructure on peri-implant health is unclear. This cross-sectional study aims to investigate the influence of the superstructure on the prevalence of peri-implant mucositis, peri-implantitis and peri-implant dysbiosis.

Methods

During a 32-month recruitment period dental implants were assessed to diagnose healthy peri-implant tissues, mucositis or peri-implantitis. The study included 1097 implants in 196 patients. Out of all peri-implantitis cases 20 randomly chosen submucosal biofilms from implants with fixed denture (FD) originating from 13 patients and 11 biofilms from implants with removable dentures (RD) originating from 3 patients were studied for microbiome analysis. Composition of transcriptionally active biofilms was revealed by RNAseq. Metatranscriptomic profiles were created for thirty-one peri-implant biofilms suffering from peri-implantitis and microbiome changes associated with superstructure types were identified.

Results

16.41% of the implants were diagnosed with peri-implantitis, 25.00% of implants with RD and 12.68% of implants with FD, respectively. Multivariate analysis showed a significant positive association on patient (p =  < 0.001) and implant level (p = 0.03) between the prevalence of peri-implantitis and RD. Eight bacterial species were associated either with FD or RD by linear discriminant analysis effect size method. However, significant intergroup confounders (e.g. smoking) were present.

Conclusions

Within the limitations of the present work, RDs appear to be a risk indicator for peri-implantitis and seem to facilitate expansion of specific periodontopathogens. Potential ecological and pathological consequences of shift in microbiome from RDs towards higher activity of Fusobacterium nucleatum subspecies animalis and Prevotella intermedia require further investigation.

Aesthetic outcomes of non-functional immediately restored single post-extraction implants with and without connective tissue graft: A multicentre randomized controlled trial

OBJECTIVES

To compare the 1-year aesthetic results of flapless single implants, placed in fresh extraction sockets with bone replacement and immediate provisional restoration with or without a connective tissue graft (CTG).

MATERIAL AND METHODS

The present study proposes a partially blinded multicentre parallel randomized controlled trial, where computer-generated tables were used for central randomization to allocate treatments. A total of 59 of the 60 patients screened by eight private practices in Northern Italy fulfilled the inclusion criteria. Immediate implants were placed in a fresh extraction socket with a non-functional immediate provisional restoration with (Test group) or without (Control group) a CTG. The primary outcome variable was the implant Crown Aesthetic Index (ICAI) at the 1-year follow-up.

RESULTS

ICAI for the 59 randomized patients (Test group = 31, Control group = 28) at the 1-year follow-up was 4.69 (95% CI = 3.16-6.22) for the Test group and 3.45 (95% CI = 1.83-5.08) for the Control group, without statistically significant difference between the two groups (p = .086). One implant failure was recorded in each group, resulting in an implant survival rate of 96.8% [95% CI = 83.3-99.9] for the Test group and 96.4% [95% CI = 81.7-99.9] for the Control group. Other secondary outcome variables and complication rates were comparable across the two groups.

CONCLUSIONS

Within the limitations of the present clinical trial, the results suggested that the adjunct use of CTG is not mandatory to achieve successful aesthetic outcomes for a well-planned immediate implant placement with immediate non-functional provisional restoration in a fresh extraction socket.

Accuracy assessment of dynamic computer-aided implant placement: a systematic review and meta-analysis

OBJECTIVES

To assess the accuracy of dynamic computer-aided implant surgery (dCAIS) systems when used to place dental implants and to compare its accuracy with static computer-aided implant surgery (sCAIS) systems and freehand implant placement.

MATERIALS AND METHODS

An electronic search was made to identify all relevant studies reporting on the accuracy of dCAIS systems for dental implant placement. The following PICO question was developed: "In patients or artificial models, is dental implant placement accuracy higher when dCAIS systems are used in comparison with sCAIS systems or with freehand placement? The main outcome variable was angular deviation between the central axes of the planned and final position of the implant. The data were extracted in descriptive tables, and a meta-analysis of single means was performed in order to estimate the deviations for each variable using a random-effects model.

RESULTS

Out of 904 potential articles, the 24 selected assessed 9 different dynamic navigation systems. The mean angular and entry 3D global deviations for clinical studies were 3.68° (95% CI: 3.61 to 3.74; I² = 99.4%) and 1.03 mm (95% CI: 1.01 to 1.04; I² = 82.4%), respectively. Lower deviation values were reported in in vitro studies (mean angular deviation of 2.01° (95% CI: 1.95 to 2.07; I² = 99.1%) and mean entry 3D global deviation of 0.46 mm (95% CI: 0.44 to 0.48 ; I² = 98.5%). No significant differences were found between the different dCAIS systems. These systems were significantly more accurate than sCAIS systems (mean difference (MD): -0.86°; 95% CI: -1.35 to -0.36) and freehand implant placement (MD: -4.33°; 95% CI: -5.40 to -3.25).

CONCLUSION

dCAIS systems allow highly accurate implant placement with a mean angular of less than 4°. However, a 2-mm safety margin should be applied, since deviations of more than 1 mm were observed. dCAIS systems increase the implant placement accuracy when compared with freehand implant placement and also seem to slightly decrease the angular deviation in comparison with sCAIS systems.

CLINICAL RELEVANCE

The use of dCAIS could reduce the rate of complications since it allows a highly accurate implant placement.

Randomized controlled clinical trial comparing implant sites augmented with a volume-stable collagen matrix or an autogenous connective tissue graft: 3-year data after insertion of reconstructions

AIM

To assess mid-term clinical, radiographic and profilometric outcomes at implant sites, previously grafted with a volume-stable collagen matrix (VCMX) or an autogenous subepithelial connective tissue graft (SCTG).

METHODS

VCMX or SCTG were randomly applied to single implant sites in 20 patients. Following abutment connection and insertion of final reconstructions (baseline), patients were re-examined at 6 months (6M), at 1 year (FU-1) and at 3 years (FU-3). Measurements included the following: clinical data, radiographic measurement of first bone to implant contact (fBIC), soft tissue thickness and volumetric outcomes. Non-parametric tests and estimates were applied for the statistical analysis.

RESULTS

The median buccal mucosal thickness increased by 0.5 mm (Q1: -0.5; Q3: 1.25) (VCMX) (p = .281) and by 0.8 mm (Q1: 0.0; Q3: 2.5) (SCTG) (p = .047) between BL and FU-3 (intergroup p = .303). The profilometric changes of the buccal soft tissues demonstrated a median decrease between BL and FU-3 of -0.2 mm (Q1: -0.5; Q3: -0.1) (p = .039) for VCMX and a decrease of -0.1 mm (Q1: -0.8; Q3: 0.1) (p = .020) for SCTG, respectively (intergroup p = .596). Peri-implant soft tissues and bone levels remained healthy throughout the entire study period. PROMs did not show any significant differences between the groups nor significant changes over time.

CONCLUSION

Minimal changes of the peri-implant tissue contour as well as of the soft tissue thickness were observed at implant sites previously grafted with VCMX or SCTG.

Nerve growth factor-chondroitin sulfate/hydroxyapatite-coating composite implant induces early osseointegration and nerve regeneration of peri-implant tissues in Beagle dogs

Background

Osseointegration is the premise of the chewing function of dental implant. Nerve growth factor (NGF), as a neurotrophic factor, can induce bone healing. However, the influence of NGF-chondroitin sulfate (CS)/hydroxyapatite (HA)-coating composite implant on the osseointegration and innervations is still not entirely clear.

Materials and methods

NGF-CS/HA-coating composite implants were prepared using the modified biomimetic method. The characteristics of NGF-CS/HA-coating implants were determined using a scanning electron microscope. After NGF-CS/HA-coating implants were placed in the mandible of Beagle dogs, the early osseointegration and innervation in peri-implant tissues were assessed through X-ray, Micro-CT, maximal pull-out force, double fluorescence staining, toluidine blue staining, DiI neural tracer, immunohistochemistry, and RT-qPCR assays.

Results

NGF-CS/HA-coating composite implants were made successfully, which presented porous mesh structures with the main components (Ti and HA). Besides, we revealed that implantation of NGF-CS/HA-coating implants significantly changed the morphology of bone tissues and elevated maximum output, MAR, BIC, and nerve fiber in the mandible of Beagle dogs. Moreover, we proved that the implantation of NGF-CS/HA-coating implants also markedly upregulated the levels of NGF, osteogenesis differentiation, and neurogenic differentiation-related genes in the mandible of Beagle dogs.

Conclusion

Implantation of NGF-CS/HA-coating composite implants has significant induction effects on the early osseointegration and nerve regeneration of peri-implant tissues in the mandible of Beagle dogs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-020-02177-5.

A Novel Solution to Treat Unesthetic Implant Restorations in the Esthetic Zone: A Case Report

INTRODUCTION

Soft tissue dehiscences and deficiencies can occur around implants especially when they are malpositioned. There is a dearth of information on burying these fixtures and bridging over them to improve the prosthetic result. The patient presented with a very functional fixed dental prosthesis (FDP) from #7 to #10 which had been in place for 20 years. The patient requested replacement of the restoration for a better esthetic outcome.

CASE PRESENTATION

The FDP was intact and did not need replacement other than for esthetic improvement. Implants were placed in the #8,9 sites and complications developed. After multiple hard and soft tissue surgeries, the case worsened. It was referred to a periodontist who reconstructed the site to ideal tissue levels. The patient had a very high smile line showing all of the soft tissue framework around the missing teeth. The prosthodontist and periodontist decided to leave the implants buried and bridged over them which resulted in an excellent esthetic outcome.

CONCLUSION

This case points out the importance of considering all possible treatment plans and involving the patient in the final decision. The seemingly apparent obvious plan would have been to restore the implants and try to achieve an esthetic result. However, after the implants were placed and developed complications, the decision to bury them improved the probability of a better esthetic outcome. The gingival levels and height of papillae were esthetically more acceptable with an FDP than what would have resulted if the fixtures were re-uncovered and restored.

Prosthodontic Principles in Dental Implantology: Adjustments in a Coronavirus Disease-19 Pandemic-Battered Economy

More patients are requesting fixed prosthesis to replace missing teeth. More than 5 million dental implants are placed annually in the United States. This number will decrease in 2020 owing to the coronavirus disease-19 pandemic. The edentulous patient has a decreased quality of life. Prosthodontic rehabilitation/reconstruction of edentulism improves overall quality of life. Patient-reported outcome measures are subjective reports of patients' perceptions of their oral health status and the impact that it has on their quality of life. This chapter contains a variety of prosthodontic principles for the reader to help satisfy the needs and expectations of the patient.

Peri-Implant Diseases: Diagnosis, Clinical, Histological, Microbiological Characteristics and Treatment Strategies. A Narrative Review

Since the use of dental implants is continuously increasing, it is imperative for dental practitioners to understand the nature and treatment of peri-implant diseases. The purpose of this manuscript is to comprehensively review peri-implant diseases, their characteristics, as well as their non-surgical and surgical treatment. To that end, the current literature was searched and a narrative review was conducted. It is essential that the case definitions described in the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions are used to diagnose and classify peri-implant health, peri-implant mucositis and peri-implantitis. While recent epidemiologic studies on peri-implant diseases exist, there is great heterogeneity in the definition of these conditions. Several risk factors and indicators are reported in the literature, with smoking and diabetes being the most universally accepted. In peri-implant mucositis, non-surgical treatment seems to be sufficient. However, for the treatment of peri-implantitis, a surgical approach, which includes open-flap debridement, apically positioned flap and guided bone regeneration, is considered more appropriate. A great variety of adjuncts to mechanical treatment have been reported with controversial results. Finally, studies comparing results from different peri-implantitis treatments are warranted in randomized controlled clinical trials in order to provide stronger evidence-based approaches.

Peri-implant soft tissue phenotype modification and its impact on peri-implant health: A systematic review and network meta-analysis

BACKGROUND

The peri-implant soft tissue phenotype (PSP) encompasses the keratinized mucosa width (KMW), mucosal thickness (MT), and supracrestal tissue height (STH). Numerous approaches to augment soft tissue volume around endosseous dental implants have been investigated. To what extent PSP modification is beneficial for peri-implant health has been subject of debate in the field of implant dentistry. The aim of this systematic review was to analyze the evidence regarding the efficacy of soft tissue augmentation procedures aimed at modifying the PSP and their impact on peri-implant health.

METHODS

A comprehensive search was performed to identify clinical studies that involved soft tissue augmentation around dental implants and reported findings on KMW, MT, and/or STH changes. The effect of the intervention on peri-implant health was also assessed. Selected articles were classified based on the general type of surgical approach to increase PSP, either bilaminar or an apically positioned flap (APF) technique. A network meta-analysis including only randomized-controlled trials (RCTs) reporting on PSP outcomes was conducted to assess and compare different techniques.

RESULTS

A total of 52 articles were included in the qualitative analysis, and 23 RCTs were included as part of the network meta-analysis. Sixteen RCTs reported the outcomes of PSP modification therapy with bilaminar techniques, whereas 7 involved the use of APF. The analysis showed that bilaminar techniques in combination with soft tissue grafts (connective tissue graft [CTG], collagen matrix [CM], and acellular dermal matrix [ADM]) resulted in a significant increase in MT compared to non-augmented sites. In particular, CTG and ADM were associated with higher MT gain as compared to CM and non-augmented sites. However, no significant differences in KMW were observed across different bilaminar techniques. PSP modification via a bilaminar approach utilizing either CTG or CM showed beneficial effects on marginal bone level stability. APF-based approaches in combination with free gingival graft (FGG), CTG, CM, or ADM showed a significant KMW gain compared to non-augmented sites. However, compared to APF alone, only FGG exhibited a significantly higher KMW gain. APF with any evaluated soft tissue graft was associated with with reduction of probing depth, soft tissue dehiscence and plaque index compared to non-augmented sites compared to non-augmented sites. The evidence regarding the effect of PSP modification via APF-based approaches on peri-implant marginal bone loss or preservation is inconclusive.

CONCLUSIONS

Bilaminar approach involving CTG or ADM obtained the highest amount of MT gain, whereas APF in combination with FGG was the most effective technique for increasing KMW. KMW augmentation via APF was associated with a significant reduction in probing depth, soft tissue dehiscence and plaque index, regardless of the soft tissue grafting material employed, whereas bilaminar techniques with CTG or CM showed beneficial effects on marginal bone level stability.

Clinical Decision Making for Primary Peri-Implantitis Prevention: Practical Applications

FOCUSED CLINICAL QUESTION

When planning dental implant therapy, what risk-reduction strategies allow practitioners to select patients, sites, and restorative plans that decrease the incidence of peri-implant disease?

SUMMARY

With a marked increase in the number of patients receiving dental implants to treat partial or complete edentulism, it follows that the prevalence of peri-implant mucositis and peri-implantitis have increased. Risks associated with implant therapies may vary based upon underlying local, environmental, surgical, patient, prosthetic, and fixture-related factors. Furthermore, an emphasis on preventative measures and maintenance should be undertaken to avoid development and progression of peri-implant diseases. Thorough risk assessment, proper treatment planning, and early diagnosis and intervention are critical in the absence of definitive data of long-term success of treatments for peri-implant condition. Given the difficulty in intervention once peri-implantitis is established, identification of risk factors and development of treatment plans to address those factors before dental implant therapy is critical to the long-term health and success of dental implants.

CONCLUSIONS

A patient-centered, evidence based approach to dental implant treatment planning to reduce the risk for peri-implantitis should be undertaken. Systematic diagnosis of disease state(s) and evaluation of the etiologic and modifying risk factors for peri-implant diseases can yield more optimal outcomes to reduce peri-implantitis rates.

Development of a Novel Medical Device for Mucositis and Peri-Implantitis Treatment

In spite of all the developments in dental implantology techniques, peri-implant diseases are frequent (prevalence up to 80% and 56% of subjects for mucositis and peri-implantitis, respectively) and there is an urgency for an effective treatment strategy. This paper presents an innovative electromedical device for the electromagnetic treatment of mucositis and peri-implantitis diseases. This device is also equipped with a measurement part for bioimpedance, which reflects the health conditions of a tissue, thus allowing clinicians to objectively detect impaired areas and to monitor the severity of the disease, evaluate the treatment efficacy, and adjust it accordingly. The design of the device was realized considering literature data, clinical evidence, numerical simulation results, and electromagnetic compatibility (EMC) pre-compliance tests, involving both clinicians and engineers, to better understand all the needs and translate them into design requirements. The reported system is being tested in more than 50 dental offices since 2019, providing efficient treatments for mucositis and peri-implantitis, with success rates of approximately 98% and 80%, respectively.

Static computer-aided, partially guided, and free-handed implant placement: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To analyze the outcomes of static computer-aided implant placement (sCAIP) compared to partially guided (PGIP) and free-handed (FHIP) implant placement.

MATERIAL AND METHODS

This study was registered in PROSPERO (CRD42019131397). A comprehensive literature search was performed by two independent examiners. Only randomized controlled trials (RCTs) were selected. Treatment modalities included sCAIP, PGIP, and FHIP. Data pertaining to the outcomes of interest were extracted. Random-effects meta-analyses were feasible for a subset of outcomes.

RESULTS

From an initial list of 2,870 records, fourteen articles for a total of ten RCTs were selected. Data from 7 of these studies allowed for the conduction of three meta-analyses comparing accuracy of implant placement across modalities. Survival rate up to 12 months post-loading was high (>98%) and comparable between treatments (low-quality evidence). No tangible differences in terms of patient perception of intra- or postoperative discomfort were observed (low-quality evidence). Quantitative analyses revealed significantly lower angular (MD = 4.41°, 95% CI 3.99-4.83, p < .00001), coronal (MD = 0.65 mm, 95% CI 0.50-0.79, p < .00001), and apical (MD = 1.13 mm, 95% CI 0.92-1.34, p < .00001) deviation values for sCAIP as compared to FHIP (8 studies, 383 patients, 878 implants, high-quality evidence). A similar discrepancy, in favor of sCAIP, was observed for angular deviation only as compared to PGIP (MD = 2.11°, 95% CI 1.06-3.16, p < .00001).

CONCLUSIONS

sCAIP is associated with superior accuracy compared to PGIP and FHIP.

Influence of implant mucosal thickness on early bone loss: a systematic review with meta-analysis

Purpose

Marginal bone loss (MBL) is an important clinical issue in implant therapy. One feature that has been cited as a contributing factor to this bone loss is peri-implant mucosal thickness. Therefore, in this report, we conducted a systematic review of the literature comparing bone remodeling around implants placed in areas with thick (≥2-mm) vs. thin (<2-mm) mucosa.

Methods

A PICO question was defined. Manual and electronic searches were performed of the MEDLINE/PubMed and Cochrane Oral Health Group databases. The inclusion criteria were prospective studies that documented soft tissue thickness with direct intraoperative measurements and that included at least 1 year of follow-up. When possible, a meta-analysis was performed for both the overall and subgroup analyses.

Results

Thirteen papers fulfilled the inclusion criteria. A meta-analysis of 7 randomized clinical trials was conducted. Significantly less bone loss was found around implants with thick mucosa than around those with thin mucosa (difference, −0.53 mm; P<0.0001). Subgroups were analyzed regarding the apico-coronal positioning, the use of platform-matched vs. platform-switched (PS) connections, and the use of cement-retained vs. screw-retained prostheses. In these analyses, thick mucosa was found to be associated with significantly less MBL than thin mucosa (P<0.0001). Among non-matching (PS) connections and screw-retained prostheses, bone levels were not affected by mucosal thickness.

Conclusions

Soft tissue thickness was found to be correlated with MBL except in cases of PS connections used on implants with thin tissues and screw-retained prostheses. Mucosal thickness did not affect implant survival or the occurrence of biological or aesthetic complications.

Trial Registration

International Prospective Register of Systematic Reviews (PROSPERO): CRD42018084598

Three-dimensional observations of the incisive foramen on cone-beam computed tomography image analysis

Purpose

The purpose of this study was to utilize cone-beam computed tomography (CBCT) image analysis to obtain anatomical information related to the morphology of the incisive foramen to provide useful data regarding implant placement and clinical procedures such as anesthesia.

Methods

The study included 167 patients who underwent CBCT scans over 20 years. Three components were measured: 1) the anteroposterior and mediolateral diameter of the incisive foramen, 2) the horizontal bone thickness anterior to the incisive foramen, and 3) the vertical bone height coronal to the incisive foramen. All measurements were expressed as mean±standard deviation and were analyzed by a single examiner.

Results

The anteroposterior diameter of the incisive foramen was wider than the mediolateral diameter (P<0.001). The diameter of the incisive foramen in patients in whom the central incisors were present was smaller than that in those in whom at least one central incisor was absent, but no statistically significant difference between the groups was observed. The horizontal bone thickness in the patients with central incisors was statistically significantly larger than that in the patients without at least one central incisor (P<0.001). The same pattern was observed with regard to vertical height, but that difference was not statistically significant.

Conclusions

The buccal bone thickness anterior to the incisive foramen was significantly decreased after central incisor loss. It is necessary to identify the morphology of the bone and the location of the incisive foramen via CBCT to avoid invasion of the incisive foramen and nasopalatine canal.

Preservation of Bone and Soft Tissue Components of the Alveolar Ridge during Immediate Implantation in the Aesthetic Zone of Jaws with Bone Deficiency

The use of immediate implantation (directly into the extracted tooth socket) in the aesthetic zone is a rather difficult task due to the specific structural features of the bone tissue of the alveolar processes and parts of the jaw. The aim of the study was to develop and evaluate the efficacy of the new method of immediate implantation during restoration of teeth in the anterior part of the jaw with bone deficiency, which allows obtaining a high aesthetic result.

Materials and Methods

The clinical study involved patients with partially edentulous anterior maxillae, chronic apical periodontitis and dental root fractures in the absence of possibility to restore these teeth with orthopedic structures. To identify the main criteria determining smile aesthetics, the detailed analysis of changes in the bone and soft tissues of the alveolar processes was made based on tooth extraction causes and dates. These criteria included gum biotype, the height of the distal and mesial interdental papillae; the width of the keratinized attached gingival area, gingival zeniths, the alveolar ridge thickness. The condition of the facial alveolar bone wall in the planned intervention area was assessed and its thickness was measured using cone-beam CT scan of the jaw. These parameters were measured during traditional immediate implantation, immediate implantation with a free connective tissue graft, implantation performed using the method developed by the authors and during delayed implantation in the anterior part. In each patient, the obtained data were compared with the results in the respective teeth area on the opposite side before the surgery, 4, 6 months and 1 year after the surgery.

Results

Clinical and X-ray studies of the developed method of immediate implantation in the aesthetic zone of the jaw with bone deficiency in the facial alveolar bone wall have convincingly demonstrated its efficacy in the long term (1 year after the surgery). The proposed protocol has made it possible to reduce the length of rehabilitation time, and most importantly, to stabilize and preserve the alveolar ridge architecture.

Conclusion

The proposed method showed the promising outlook for dental implant-supported restoration in difficult anatomical conditions.

Standard vs customized healing abutments with simultaneous bone grafting for tissue changes around immediate implants. 1-year outcomes from a randomized clinical trial

BACKGROUND

Immediate implants have shown risks of esthetic complications. The hypothesis was that a customized healing abutment could improve the peri-implant tissue healing.

PURPOSE

To evaluate and compare the soft and hard tissue healing around immediate implants that received bone grafting and a customized vs a standard healing abutment.

MATERIALS AND METHODS

Patients, who required tooth extraction and who received an immediate implant (with an alloplastic graft material) were randomly assigned to a customized or a standard healing abutment group. Clinical and radiographic examinations were taken at baseline, at 4 and 12 months.

RESULTS

Twenty-five patients out of 61 were excluded from the study because unsuitable for immediate implantation. In total, 36 patients were randomized in the two groups. There were 17 females and 19 males (age range 23-77). No prosthetic or implant failure was registered during the study period. The Papilla Index was significantly higher in the customized than in the standard group at 4 and 12 months (P = .0002). The bone loss at mesial sites was significantly higher in the control than in the test group (P = .0014).

CONCLUSION

The customized healing abutment group showed the most favorable outcomes (in terms of PI and MBL) in case of immediate implant that received a peri-implant bone grafting procedure.

Concepts for prevention of complications in implant therapy

The use of dental implants is nowadays a well-accepted and highly predictable treatment modality for restoring the dentition and reestablishing the masticatory function of edentulous and partially edentulous patients. Despite the high predictability and excellent long-term survival rates reported for implant therapy, complications may still occur and can jeopardize both short- and long-term success. The present paper provides an overview on the most important aspects related to the etiology, prevention, and management of complications associated with implant therapy. Data from the literature indicate that a number of factors, such as surgical trauma, implant diameter, type of implant-abutment connection, abutment disconnection and reconnection, presence of microgap, and implant malpositioning, can substantially influence the biologic processes of bone remodeling and biofilm formation, thus increasing the rate of short- and long-term hard- and soft-tissue complications. Other factors, such as excess cement at cement-retained prosthetic restorations, abutment mobility, and infections (e.g. peri-implant mucositis and peri-implantitis) caused by bacterial biofilm, are further causes for complications and failures. More recent evidence also indicates that besides the need for sufficient bone volume surrounding the implant, the presence of an adequate width and thickness of attached mucosa may improve biofilm control and limit crestal bone resorption. Furthermore, emerging evidence points also to the pivotal role of human factors as one of the most important causes of complications in implant dentistry. It can be concluded that clinicians need to consider all biologic and biomechanical factors affecting implant placement and survival, as well as undergo adequate training to improve their surgical skills to control and prevent implant complications. Careful patient selection and control of environmental and systemic factors, such as smoking, diabetes etc., coupled with an accurate surgical and prosthetic planning, enable a better prevention and control of infections.

Peri-implant diseases and conditions: Consensus report of workgroup 4 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions

A classification for peri-implant diseases and conditions was presented. Focused questions on the characteristics of peri-implant health, peri-implant mucositis, peri-implantitis, and soft- and hard-tissue deficiencies were addressed. Peri-implant health is characterized by the absence of erythema, bleeding on probing, swelling, and suppuration. It is not possible to define a range of probing depths compatible with health; Peri-implant health can exist around implants with reduced bone support. The main clinical characteristic of peri-implant mucositis is bleeding on gentle probing. Erythema, swelling, and/or suppuration may also be present. An increase in probing depth is often observed in the presence of peri-implant mucositis due to swelling or decrease in probing resistance. There is strong evidence from animal and human experimental studies that plaque is the etiological factor for peri-implant mucositis. Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. Peri-implantitis sites exhibit clinical signs of inflammation, bleeding on probing, and/or suppuration, increased probing depths and/or recession of the mucosal margin in addition to radiographic bone loss. The evidence is equivocal regarding the effect of keratinized mucosa on the long-term health of the peri-implant tissue. It appears, however, that keratinized mucosa may have advantages regarding patient comfort and ease of plaque removal. Case definitions in day-to-day clinical practice and in epidemiological or disease-surveillance studies for peri-implant health, peri-implant mucositis, and peri-implantitis were introduced. The proposed case definitions should be viewed within the context that there is no generic implant and that there are numerous implant designs with different surface characteristics, surgical and loading protocols. It is recommended that the clinician obtain baseline radiographic and probing measurements following the completion of the implant-supported prosthesis.

Denture-reversing technique for assessing the soft tissue dimensional changes according to artificial tooth position in completely edentulous patients

A digital workflow to assess the soft tissue dimensional changes in completely edentulous patients is described. Diagnostic casts obtained at 2 time points and the complete denture were scanned by using a desktop scanner. The denture scan was inverted by using a metrology software program to obtain the soft tissue contour. Using this reversed file as a reference, the file and 2 scan files obtained at different time points were aligned individually with the best fit alignment function. The scanned denture file and the 2 realigned scan files were imported into the same software. A plane vertical to the occlusal plane was determined such that it moved anteroposteriorly. The distance between the contours of the 2 realigned files was measured by selecting a point and a vector based on the artificial tooth positions of the denture. This technique of using a reversed denture file may provide a quantitative evaluation of soft tissue changes and further aid in determining appropriate intervals for denture relining or rebasing.

Does traumatic occlusal forces lead to peri-implant bone loss? A systematic review

Observational studies have indicated that crestal bone level changes at implants are typically associated with clinical signs of inflammation, but still mechanical overload has been described as possible factor leading to hard-tissue deficiencies at implant sites without mucosal inflammation. The aim of this paper was systematically review the literature regarding the possible effect of traumatic occlusal forces on the peri-implant bone levels. Literature search was conducted using PubMed, Scielo and Lilacs, including the following terms: oral OR dental AND implant$ AND (load OR overload OR excessive load OR force$ OR bruxism) AND (bone loss OR bone resorption OR implant failure$). Databases were searched for the past 10 years of publications, including: clinical human studies, either randomized or not, cohort studies, case control studies, case series and animal research. Exclusion criteria were review articles, guidelines and in vitro and in silico (finite element analysis) research, as well as retrospective studies. The PICO questions formulated was: "does traumatic occlusal forces lead to peri-implant bone loss?" The database searches as well as additional hand searching, resulted in 807 potentially relevant titles. After inclusion/exclusion criteria assessment 2 clinical and 4 animal studies were considered relevant to the topic. The included animal studies did not reveal an association between overload and peri-implant bone loss when lower overloads were applied, whereas in the presence of excessive overload it seemed to generate peri-implant bone loss, even in the absence of inflammation. The effect of traumatic occlusal forces in peri-implant bone loss is poorly reported and provides little evidence to support a cause-and-effect relationship in humans, considering the strength of a clinically relevant traumatic occlusal force.

Is the re-use of sterilized implant abutments safe enough? (Implant abutment safety)

Background: The reuse of implant healing abutments is common in dental practice. Effective elimination of bacteria and viruses is accomplished by conventional sterilization. The aim of this work was to explore the eventual survival of microorganisms on sterilized healing abutments and to rule out the presence of transmissible organic material after standard procedures. Material and Methods: A total of 55 healing abutments previously used in patients will be washed and sterilized in a steam autoclave at 121ºC for 15 min. Each healing abutment will be cultured in Brain Heart Infusion broth (BHI) under strict aseptic conditions. Besides, two control groups will be included: one of 3 unused healing abutments, and the other of just medium. After 10 days at 37°C under a 5% CO2 100 µl of the broth will be plated on solid media (Brain Infusion Agar, BHIA) and Columbia Blood agar to test for sterility. The remaining volume will be centrifuged, the sediment fixed, and a Gram stain performed to discard the presence of non-cultivable microorganisms. Moreover, to determine the presence of remaining organic material after the cleaning and sterilizing treatments, the bioburden will be determined by measuring total organic carbon (TOC) in another 10 previously used healing abutments, cleaned and sterilized, that will be submerged in Milli-Q water and sonicated. Results: No bacterial growth was detected on any of the 58 cultured abutments, indicating that the sterilization was completely satisfactory in terms of removal of live bacteria or spores. Nevertheless, significant amounts of organic carbon may still be recovered (up to 125,31 µg/abutment) after they have been sterilized. Conclusions: Significant amounts of the bioburden remained adhered to the surfaces in spite of the cleaning and sterilization procedures. Taking into account our results and data from other authors, the presence of infectious particles on the reused healing abutments such as prions cannot be ruled out.

Key words:Healing abutment, abutment surface, peri-implantitis, mucositis, sterilization.