Clinical outcomes of implants placed with transcrestal maxillary sinus elevation: a systematic review and meta-analysis.

This systematic review and meta-analysis assesses the clinical outcomes of implants inserted during or following transcrestal sinus lifts. The study protocol was prospectively registered on PROSPERO (CRD42024504513). PubMed, Web of Science, Embase, and Scopus databases were searched up to 21 February 2024, and randomised clinical trials utilising transcrestal sinus lifts were included. Qualitative and quantitative syntheses were conducted. A random effects model was used to pool the survival rate of implants placed with transcrestal sinus lifts using hand osteotomes without grafting, along with meta-regression and subgroup analyses. Funnel plots and Egger's linear regression were used to explore possible publication bias. Probabilities of less than 0.05 were considered significant. A total of 1807 records were identified after the initial search. Seventeen studies were included with 10 of them considered for meta-analysis. Studies used hand osteotomes, a combination of piezoelectric and hand osteotomes, drills, and smart lifts for sinus elevation. Only studies that used hand osteotomes reported subsequent vertigo and dizziness in patients. The meta-analysis showed a 100% (95% CI: 99% to 100%) survival rate for both grafted and non-grafted transcrestal sinus lifts using hand osteotomes. Meta-regression showed that follow-up time did not significantly affect the implants' survival. Subgroup analyses showed no significant difference between bone-level and tissue-level implants and one-stage or two-stage implants. On considering the limitations of this study it can be concluded that closed maxillary sinus elevation can be considered a relatively safe technique that is associated with a high survival rate. However, caution should be taken when using hand osteotomes because of a higher rate of sinus lining perforation and reported patient vertigo.

Risk Indicators of Peri-Implant Diseases in Public and Private Clinics: A Multicenter Study.

Methods: Patients examined during postloading maintenance visits were included in this study. The presence of peri-implant mucositis, peri-implantitis and several patient- and implant-related independent variables was recorded. Statistical analysis was performed using the logistic regression analysis. The odds ratios (OR) of the potential association between each variable and the occurrence of peri-implant diseases were evaluated. Results: Among the 114 participants with 403 implants, peri-implantitis was found in at least one implant of nine individuals (7.89%), and a total of 13 implants were affected by peri-implantitis (3.22%). The univariate regression analysis revealed a statistically significant association between arch (OR = 4.81; 95% CI = 1.27-31.36) and soft tissue thickness (OR = 4.07; 95% CI = 1.33-13.73) with the occurrence of peri-implantitis. The multivariate analysis confirmed the significant impact of soft tissue thickness (OR = 3.60; 95% CI = 1.16-12.24). Conclusion: The occurrence of peri-implant diseases can be influenced by various factors. However, in order to accurately identify risk indicators, it is necessary to conduct long-term prospective studies.

A new guide for enhancing dental implant placement: an in vitro assessment of accuracy.

This study aimed to design a new surgical guide for controlling the mesiodistal distance between implant osteotomies and adjacent teeth as well as the osteotomy depth in partially edentulous patients. The guide kit was designed with design software and milled with a CNC (computer numerical control) router. The guide consisted of 2 components-stoppers and crown guides-for determining the drilling depth and mesiodistal position, respectively. The stoppers were designed in 7.5-, 9.5-, and 11.5-mm lengths, and the crown guides were fabricated with outer diameters of 5.0, 6.0, 7.0, and 8.0 mm. The accuracy of the guide was assessed by preparing a total of 20 implant osteotomies in 4 partially edentulous models and comparing the dimensions of the actual osteotomies to the values that were predicted to occur with the use of the surgical guides. Osteotomies were prepared using the 7.5-mm stopper with either the 7.0- or 8.0-mm crown guide. Cone beam computed tomography (CBCT) was used to obtain images for analysis of osteotomy-tooth mesiodistal distances, which were predicted to be 3.0 or 5.5 mm, depending on position; interosteotomy mesiodistal distances, which were predicted to be 3.0 mm; and osteotomy depth, which was predicted to be 11.5 mm. A 1-sample t test was used to determine if there were significant differences between the predicted values and the measurements of the guided osteotomies on the CBCT images of the mandibular models, and an independent t test was conducted to compare the results of 3.0- and 5.5-mm osteotomy-tooth distances (α = 0.05). Differences between the predicted and actual values of the interosteotomy mesiodistal distance (P = 0.516) and osteotomy depth (P = 0.847) were not statistically significant. The actual osteotomy-tooth mesiodistal distances were significantly different from the predicted values of 3.0 (P = 0.000) and 5.5 mm (P = 0.001), with higher mean differences of 0.46 and 0.60 mm, respectively. The designed guide had a high accuracy in achieving optimal linear interosteotomy mesiodistal distances and osteotomy depths, and the obtained mean values were clinically acceptable.

Comparison of the healing process of xenografts with three different sources in critical-size bone defects: An in vivo study.

Background: Xenograft bone substitutes can be obtained from different animals and processed using various methods. The present in vivo study evaluated bone regeneration after using three types of xenografts with different sources in critical-sized bone defects in rabbit calvaria. Methods: Four 8-mm defects were created in calvaria of 14 New Zealand and white male rabbits. Three out of four defects were filled with xenografts of bovine, camel, and ostrich sources. The fourth defect was left unfilled as the control group. Seven rabbits were sacrificed after eight weeks and seven others after 12 weeks. Micro-CT imaging and histologic evaluation were further performed on dissected calvarias. Results: After 8 and 12 weeks, the highest and lowest percentages of new bone formation were observed in the camel (27.71% and 41.92%) and control (11.33% and 15.96%) groups, respectively. In the case of residual material, the ostrich group had the most value after eight weeks (53%), while after 12 weeks, it was highest in the camel group (37%). Micro-CT findings were consistent with histologic results. Conclusion: Although all three xenografts can be good choices for treating bone defects, camel-sourced xenograft seemed to be better than the other two groups. The origin and processing procedures of xenografts affected their final characteristics, which should be considered for clinical use.

Comparative assessment of the physical structure of antler and bovine bone substitutes: An in vitro study.

Background: The use of bone graft materials has significantly increased. Given the inherent variations in structure and functionality between different grafting materials, this evaluated and compared the physical attributes of antler and bovine femur bone substitutes. Methods: In the present in vitro investigation, the surface morphological architecture of the two bone substitutes with different origins was assessed through scanning electron microscopy. Furthermore, the Brunauer-Emmett-Teller (BET) technique was employed to measure the porosity, specific surface area (SSA), and pore morphology. Results: Scanning electron microscopy observations indicated that the surface of the bovine particles appeared smoother, while the antler particles exhibited a rougher surface texture. The BET analysis revealed that both samples exhibited identical pore morphology. The SSA was 15.974 m2/g in the antler particles compared with 18.404 m2/g in the bovine sample. The total porosity volume in the antler and bovine femur bone substitutes were 0.2172 cm3/g and 0.2918 cm3/g, respectively. Additionally, the antler particles had a porosity percentage of 40%, whereas the bovine femur bone substitute showed a porosity percentage of 43.5%. Conclusion: Based on the results of this study, it seems that the two samples of bone grafting materials have comparable physical structures.

M2 macrophage-derived exosomes for bone regeneration: A systematic review.

OBJECTIVE: This systematic review aims to evaluate existing evidence to investigate the therapeutic efficacy of M2 macrophage-derived exosomes in bone regeneration. DESIGN: A comprehensive search between 2020 and 2024 across PubMed, Web of Science, and Scopus was conducted using a defined search strategy to identify relevant studies regarding the following question: "What is the impact of M2 macrophage-derived exosomes on bone regeneration?". Controlled in vitro and in vivo studies were included in this study. The SYRCLE tool was used to evaluate the risk of bias in the included animal studies. RESULTS: This review included 20 studies published. Seven studies were selected for only in vitro analysis, whereas 13 studies underwent both in vitro and in vivo analyses. The in vivo studies employed animal models, including 163 C57BL6 mice and 73 Sprague-Dawley rats. Exosomes derived from M2 macrophages were discovered to be efficacious in promoting bone regeneration and vascularization in animal models of bone defects. These effects were primarily confirmed through morphological and histological assessments. This remarkable outcome is attributed to the regulation of multiple signaling pathways, as evidenced by the findings of 11 studies investigating the involvement of miRNAs in this intricate process. In addition, in vitro studies observed positive effects on cell proliferation, migration, osteogenesis, and angiogenesis. Heterogeneity in study methods hinders direct comparison of results across studies. CONCLUSION: M2 macrophage-derived exosomes demonstrate remarkable potential for promoting bone regeneration. Further research optimizing their application and elucidating the underlying mechanisms can pave the way for clinical translation.

An Analysis of Scientific Research Trends in Oral Implantology Between 2016 and 2022.

The present study aims to evaluate the trends of oral implant-related research in design and topics between the range of 2016 to the end of 2022. The electronic search was conducted in MEDLINE via Pubmed. Papers published in Clinical Oral Implant Research, Clinical Implant Dentistry and Related Research, and International Journal of Oral Implantology as well as previously European Journal of Oral Implantology, International Journal of Oral and Maxillofacial Implants, and Journal of Oral Implantology between January 1, 2016, and December 30, 2022, were retrieved. Articles were classified according to their study design and major subjects. The Joinpoint regression model was used to determine changes in the trends of study designs and topics. Statistical significance was defined as a p-value <.05. A total of 3382 articles were analyzed in this study. In the specified period, in vivo, prospective cohort, retrospective case control, randomized clinical studies in the design and prosthetic complications, peri-implant hard tissue studies in the topic experienced a significant decreasing pattern in the number of published articles as well as the total number of articles. Case reports and series, retrospective cohort, nonrandomized clinical studies in the design and outcomes of implant-related treatment plans, immediate implant placement, and peri-implantitis in the topic experienced a significant decreasing pattern followed by a significant increasing pattern with a turning point between 2017 and 2020. Considering the limitations of this scientific topical trend analysis, it can be concluded that the recent pandemic affected the research path in oral implantology in many ways.

Time management in multistep periodontal and implant treatments: a practical guide.

In addition to the proper selection of techniques, appropriate treatment sequencing and prioritization are prerequisites for successful periodontal and implant procedures. The aim of this study was to provide evidence-based time frames for various procedures pertaining to periodontal and implant treatment. A literature review was conducted to collect data on tissue healing; in areas in which data were lacking, the viewpoints of experienced clinicians were solicited to establish a consensus. This review reports recommended time frames for the healing processes associated with surgical crown-lengthening procedures (both functional and esthetic), fresh socket management, alveolar ridge management, soft tissue management, sinus floor augmentation, implant loading, and peri-implant defect management.

Comparison of the Volume and Histological Properties of Newly Formed Bone after the Application of Three Types of Bone Substitutes in Critical-Sized Bone Defects.

This study aimed to compare the volume and quality of the newly formed bone following application of two types of xenografts and one synthetic material in bone defects in rabbit calvaria from histological and micro-CT aspects. Four 8-mm defects were created in 12 rabbit calvaria. Three defects were filled with bone substitutes and one was left unfilled as the control group. The newly formed bone was evaluated histologically and also by micro-CT at 8 and 12 weeks after the intervention. The percentage of osteogenesis was comparable in histomor-phometric assessment and micro-CT. Histological analysis showed that the percentage of the newly formed bone was 10.92 ± 5.17%, 14.70 ± 11.02%, 11.47 ± 7.04%, and 9.45 ± 5.18% in groups bovine 1, bovine 2, synthetic, and negative control, respectively after 8 weeks. These values were 33.70 ± 11.48%, 26.30 ± 18.05%, 22.92 ± 6.30%, and 14.82 ± 8.59%, respectively at 12 weeks. The difference in the percentage of the new bone formation at 8 and 12 weeks was not significant in any group (P > 0.05) except for bovine 1 group (P < 0.05). Micro-CT confirmed new bone formation in all groups but according to the micro-CT results, the difference between the control and other groups was significant in this respect (P < 0.05). All bone substitutes enhanced new bone formation compared with the control group. Micro-CT assessment yielded more accurate and different results compared with histological assessment.

Potentials of pure xenograft materials in maxillary ridge augmentation: A case series.

Many patients require edentulous ridge augmentation for dental implant placement. The main objective of this study was to evaluate the results of maxillary edentulous ridge augmentation exclusively with xenograft materials with and without simultaneous sinus floor elevation. This study reports the data retrieved from the records of 16 patients. The treatment outcome was assessed at least 6 months, postoperatively. Paired samples t-test or Wilcoxon Signed Rank test was used to compare the pre-and postoperative ridge dimensions. Dental implants were placed simultaneously in 7 patients, while 9 patients underwent delayed implant placement. In total, 68 implants were placed, and 12 patients also underwent maxillary sinus floor augmentation. A significant bone gain was achieved in both horizontal and vertical dimensions of edentulous maxillary ridges (P < 0.001). Ridge width increased by an average of 4.35 ± 1.90 mm (95% CI: 3.84 to 4.85 mm) while ridge height in areas of sinus floor augmentation increased by 8.19 ± 2.91 mm (95% CI: 7.33 to 9.05 mm). Within the study limitations, it appears that maxillary ridge augmentation according to the guided bone regeneration (GBR) protocols with exclusive use of xenograft particulate materials can provide optimal bone quantity for dental implant placement.

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.

Periodontal phenotype modification in orthodontic patients.

OBJECTIVE: The purpose of this study was to assess the feasibility of phenotype modification in orthodontic patients using combined bone and soft tissue grafting substitutes. CLINICAL CONSIDERATION: The surgical procedure was conducted on 18 patients (3 males, 15 females). Periodontal phenotype modification was conducted using demineralized freeze-dried bone allograft and a xenogeneic collagen matrix. The following parameters were recorded for each tooth at baseline and 12-month follow-up: O'Leary plaque index (PI), probing depth (PD), bleeding on probing (BOP), gingival thickness (GT), keratinized tissue width (KTW), gingival recession (GR), and vestibular depth (VD). The results showed a statistically significant increase in GT (2.02 ± 0.39 mm), KTW (1.11 ± 0.82 mm), and VD (0.18 ± 1.16 mm) (p < 0.05). GR was also significantly decreased (1.02 ± 0.99 mm) (p < 0.05). CONCLUSION: Within the limitation of this study, the proposed approach enhanced the periodontal condition in orthodontic patients. However, further studies with a larger sample size are needed to ensure long-term stability. CLINICAL SIGNIFICANCE: Hard and soft tissue conditions have paramount importance for long-term periodontal stability. Phenotype modification in orthodontic patients can diminish the probability of adverse consequences and result in optimal esthetic outcomes. The proposed technique using combined bone and soft tissue substitutes indicated promising results and could be recommended in orthodontic patients with thin periodontal phenotypes.

In situ shell technique for edentulous ridge augmentation.

BACKGROUND: The novel two-stage technique presented in this study is based on guided bone regeneration for three-dimensional bone augmentation. METHODS AND RESULTS: The proposed technique was performed to augment an atrophic alveolar ridge in the maxilla and mandible. This method is based on using an autogenous bone plate, a mixture of allogeneic bone graft and injectable -platelet-rich fibrin, and a bioresorbable barrier membrane. Based on the cases presented in this study, sufficient osseous regeneration was achieved to place dental implants in an ideal position. CONCLUSION: Within the limitations of the present study, it seems that in situ shell technique could be a beneficial method to augment the extremely atrophied ridges with less morbidity and shorter operative time. KEY POINTS: Why is this case new information? The cases presented a new technique using in situ autogenous plates for ridge augmentation. What are the keys to the successful management of this case? The keys to the successful management of these cases are proper flap management and less traumatic bony plate preparation. What are the primary limitations to success in this case? The primary limitation to success in this technique would be a need for high surgical skills to conduct the procedure accurately.

Sterility and bioactivity evaluation of two types of bone graft substitutes after removing the original packaging.

Background: Xenograft and allograft bone substitutes are widely used to replace the missing bone in defects. Since removing the packaging of these grafts can nullify their sterilization, this study aimed to evaluate the sterility and bioactivity changes of an allograft and a xenograft following uncapping/recap. Methods: Two types of commercial allograft and xenograft vials were unpacked and further exposed to operating room air, where implant surgery was performed for one second, ten minutes, and one hour. After three repetitions, samples were analyzed using microbiological tests and scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDX) for sterility and bioactivity evaluation. Results: None of the bone graft samples showed microbial growth or bioactivity-negative changes after seven days of unpacking the vials. Conclusion: Despite the positive results of this study, future studies and more analysis considering influential factors are required. Also, disinfection and air exchange must still be observed during biomaterial application and bone grafting procedures.

Explantation Site Management: A Decision Algorithm for Re-Implantation.

Dental implants are currently the preferred choice to restore function and esthetics. Nonetheless, explantation is sometimes inevitable in cases with advanced bone loss, implant fracture, or improper implant position. This study aimed to propose an algorithm for reimplantation at sites of previous failure. There is limited evidence on the replacement of failed implants, most of which are case reports or clinical trials with a small number of patients. To the best of the authors' knowledge, this is the first study proposing a clinical-decision algorithm to help clinicians manage implant failures with new implants. There are a variety of reasons contributing to implant failure: The etiologic factor of failure and the morphology of the residual defect have paramount importance on implant removal techniques and subsequent treatment modalities. There is no consensus on a distinct protocol to replace failed implants. However, the clinicians and patients should know that placing a new implant in an area with a history of failure, regardless of early or late implant failure, may have a lower survival rate.

Peri-Implant Tissue Health and Disease in the Pre- and Post-Loading Phases.

Considering the widespread use of dental implants, a precise definition for peri-implant tissue health and an appropriate classification for peri-implant diseases are imperative for researchers and dental clinicians. However, absence of a unanimous definition and an efficient classification system has created controversies in the published reports regarding the epidemiology and prevalence of peri-implant diseases. Moreover, lack of a standard system for differentiation of different grades of peri-implantitis further complicates the interpretation of reports regarding the diagnosis prevalence, treatment, and outcome of such conditions, and highlights the need for a classification system based on the severity of disease. Almost all of the currently available classification systems focus on the assessment of health or disease status of the tissues around loaded implants. The purpose of the present study is to propose a classification/scoring system for peri-implant tissue health before and after prosthetic loading. This grading system can aid the researchers and dental clinicians in assessment of peri-implant tissue condition both before and after prosthetic loading of dental implants.

Short-term and long-term success and survival rates of implants supporting single-unit and multiunit fixed prostheses: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Whether placing implants to replace each missing tooth or using implant-supported fixed partial dentures provides better outcomes is unclear. PURPOSE: The purpose of this systematic review and meta-analysis was to assess the success and survival rates of implants supporting single-unit and multiunit fixed prostheses by using conventional protocols for placement and loading in short- and long-term follow-ups. MATERIAL AND METHODS: An electronic search was conducted in PubMed, Scopus, and Web of Science for studies published up to March 17, 2022. Comparative studies that reported the success or survival rates of both single-unit and splinted multiunit prostheses were considered for qualitative and quantitative analyses. RESULTS: A total of 68 publications comprising 11 271 implants were included. Compared with the single prostheses, the splinted multiunit group showed no significant differences in implant success rates in the short-term (risk difference=-0.004; 95% confidence interval (CI)=-0.033 to 0.025; P=.780) and long-term (risk difference=0.003; 95% confidence interval (CI)=-0.029 to 0.034; P=.874) follow-ups. Significant statistical differences were also not found in terms of the survival rates of the 2 groups (short-term risk difference=-0.004; 95% CI=-0.031 to 0.023; P=.779, long-term risk difference=-0.002; 95% CI=-0.029 to 0.025; P=.887). CONCLUSIONS: Implants supporting single-unit or splinted multiunit prostheses seem to be a predictable treatment in terms of survival and success over short and long periods. Nonetheless, it seems that cantilever and nonsplinted multiunit prostheses should be used with more caution.

Immediate implant placement in compromised sockets: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Immediate implant placement provides a popular therapeutic option. However, compromised sockets may jeopardize the treatment outcome. PURPOSE: The purpose of this systematic review and meta-analysis was to investigate the treatment outcome in terms of the implant survival rate and success parameters of immediate implant placement in compromised extraction sockets. MATERIAL AND METHODS: An electronic search was conducted in PubMed, Embase, Cochrane Library, and ISI Web of Science up to January 2021. Studies evaluating implant survival rate and main success parameters were included for a qualitative and quantitative analysis (risk ratio and mean difference). RESULTS: In total, 43 studies with analysis of 4825 sockets were included. Compared with the noncompromised sockets, the compromised group showed no significant differences in implant survival rates (risk ratio=0.992; 95% confidence interval (CI)=0.979 to 1.005; P=.246). No significant statistical differences were found in marginal bone level at ≤12 months (mean difference [MD]=0.033; 95% CI=-0.012 to 0.078; P=.154) or esthetic parameters. CONCLUSIONS: Immediate implant placement in compromised sites does not appear to decrease the survival and success rates. However, randomized clinical trials with large sample sizes should be conducted to draw a definite conclusion about the efficacy and safety of this treatment protocol in compromised sockets.

Biological reactions of dental pulp stem cells cultured in presence of new xenograft bone substitutes from different sources: An in vitro study.

Aims: This study aimed to compare the biological reactions of dental pulp stem cells (DPSCs) cultured on new xenograft bone substitutes derived from camel and bovine bones. Materials and Methods: DPSCs were cultured and placed on different xenograft materials including Bone Plus (bovine), Camel Bone, and demineralized bovine bone matrix. The viability and proliferation of cells were evaluated by the methyl thiazolyl tetrazolium assay after 24, 48, and 72 h. The alkaline phosphatase (ALP) test and Alizarin red staining were performed at 7 and 21 days to assess the osteoblastic differentiation of cells. Osteocalcin (OCN) gene expression was evaluated qualitatively at 3-, 7- and 14-days using polymerase chain reaction (PCR). Semi-quantitative PCR was also performed using ImageJ software. Data were analyzed by ANOVA and Tukey's honestly significant difference test. Results: The cell proliferation rate was significantly different among the three xenograft bone substitutes at 24-, 48- and 72 h (P < 0.05). The ALP activity of DPSCs in all three xenograft bone substitute groups was greater than that in the control group (P < 0.05). Alizarin red staining showed no significant difference in the formation of calcified nodules among the groups. Qualitative and semi-quantitative PCR displayed that the expression of OCN gene in the Camel Bone and Bone Plus groups was higher than that in the demineralized bovine bone matrix group. Conclusions: The Camel Bone xenograft caused a high proliferation rate and optimal osteogenic differentiation of DPSCs qualitatively and semi-quantitatively in vitro. Further studies are required on this xenograft bone substitute.

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

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