A hybrid unsupervised clustering method for predicting the risk of dental implant loss

OBJECTIVES

The aim of this study was to predict the risk of dental implant loss by clustering features associated with implant survival rates.

MATERIALS AND METHODS

Multiple clinical features from 8513 patients who underwent single implant placement were retrospectively analysed. A hybrid method integrating unsupervised learning algorithms with survival analysis was employed for data mining. Two-step cluster, univariate Cox regression, and Kaplan‒Meier survival analyses were performed to identify the clustering features associated with implant survival rates. To predict the risk of dental implant loss, nomograms were constructed on the basis of time-stratified multivariate Cox regression.

RESULTS

Six clusters with distinct features and prognoses were identified using two-step cluster analysis and Kaplan‒Meier survival analysis. Compared with the other clusters, only one cluster presented significantly lower implant survival rates, and six specific clustering features within this cluster were identified as high-risk factors, including age, smoking history, implant diameter, implant length, implant position, and surgical procedure. Nomograms were created to assess the impact of the six high-risk factors on implant loss for three periods: 1) 0-120 days, 2) 120-310 days, and 3) more than 310 days after implant placement. The concordance indices of the models were 0.642, 0.781, and 0.715, respectively.

CONCLUSIONS

The hybrid unsupervised clustering method, which clusters and identifies high-risk clinical features associated with implant loss without relying on predefined labels or target variables, represents an effective approach for developing a visual model for predicting implant prognosis. However, further validation with a multimodal, multicentre, prospective cohort is needed.

CLINICAL SIGNIFICANCE

Visual prognosis prediction utilizing this nomogram that predicts the risk of implant loss on the basis of clustering features can assist dentists in preoperative assessments and clinical decision-making, potentially improving dental implant prognosis.

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.

The impact of antiplatelet and anticoagulant medications on early implant failure following sinus floor augmentation: A retrospective cohort analysis

INTRODUCTION

The effect of antiplatelet and anticoagulant medications on the outcomes of sinus floor augmentation remains unclear.

METHODS

This retrospective cohort study analyzed data from electronic medical records of consecutive patients undergoing sinus floor augmentation at a single medical center. Patients were categorized into three categories: patients under antiplatelet medications, patients under anticoagulation medications, and healthy individuals. Data collected included tobacco smoking, residual alveolar bone height, timing of implant placement, materials used, vertical bone gain, early implant failure (EIF), and complications such as Schneiderian membrane perforation and postoperative bleeding. Multivariable analysis was performed to assess risk factors for EIF. Statistical significance was considered below 5%.

RESULTS

Among 110 patients with 305 implants, EIF occurred in 10% of patients and 4.65% of implants. No significant difference in postoperative bleeding or EIF was found between study groups. Univariate and multivariable analyses highlighted tobacco smoking (odds ratio [OR] = 7.92), lower residual alveolar ridge height (OR = 0.81), and staged implant placement (OR = 4.64) as significant EIF risk factors in this cohort.

CONCLUSIONS

Anticoagulant and antiplatelet therapies do not significantly elevate the risk of EIF or postoperative bleeding following sinus floor augmentation. Tobacco smoking, residual alveolar ridge height and staged sinus floor augmentation were risk factors for EIF in patients using antiplatelet or anticoagulation medications undergoing sinus floor augmentation.

Risk Factors for Implant Failure Following Transcrestal Sinus-Floor Elevation: A Case Report and Literature Review

Although transcrestal sinus floor elevation (TSFE) is widely used for cases of insufficient residual bone height in the posterior maxilla, few studies focus on the risk factors of early implant failure associated with TSFE procedures. This study aimed to identify and summarize the possible risk factors of implant failure associated with TSFE to ensure a more predictable implant survival rate using TSFE. We report the treatment of a patient with implant failure following TSFE and discuss this case's possible associated risk factors. A standard implant with a diameter of 4.8 mm and length of 10 mm was used after the TSFE procedure. Implant loosening was suddenly observed 6 weeks after the initial surgery. Factors that could result in early implant failure included patient-related risk factors, anatomical factors of the operational area, and operation- and implant-related factors. Within the current study's limitations, the graft material particles between the implant surface and socket could be considered a direct risk factor resulting in implant failure. Therefore, more attention should be paid to socket cleaning during the TSFE procedure, and loose particulate grafting materials should be discouraged. Another significant consideration for implant loss is the possibility of fractures in the buccal or palatal cortical plates during the site preparation and implant insertion. Thus, these factors should be studied further and receive more clinical attention.

Risk factors associated with early implant failure: A retrospective review

PURPOSE

The purpose of this study was to investigate the association between possible risk factors and early implant failure.

PATIENTS AND METHODS

This retrospective cohort study included consecutive patients receiving dental implant treatment in a four-year timeframe. Patient-related variables (age, sex, smoking, and systemic disease), local factors (area, reason for tooth extraction, and bone quality), surgical variables (bone augmentation, time of implant placement, staging, and antibiotic prophylaxis), and implant-related factors (brand, length, and diameter) were analyzed. Bivariate analyses and multivariate logistic regression model were used to determine the variables associated with early implant failure.

RESULTS

The study group comprised 1323 implants in 738 patients with a mean of 1.8 implants/patient of which, 53 failed in 52 patients in the early stage (before final prosthetic loading). According to the multivariate model, smoking (Odds Ratio=1.836, P=0.031), posterior maxillary region (OR=2.958, P=0.006), implantation in place of teeth extracted due to periodontal problems (OR=2.531, P=0.004), bone type IV (OR=2.881, P=0.008), implant in previously augmented site (OR=2.239, P=0.014), and immediate provisional prosthesis (OR=3.418, P=0.019) were associated with a significantly higher risk of early implant failure. Narrow implants showed a significantly higher risk of early failure in bivariate analyses (P=0.012). However, the effect was no longer significant in the multivariate model (OR=2.322, P=0.068).

CONCLUSION

Early implant failure would be more expected in smokers, posterior maxilla, history of periodontal problems, type IV bone, augmented bone, and immediately loaded cases.

Impact of peri-implant keratinized mucosa width on the long-term reconstructive outcomes of peri-implantitis: A retrospective analysis with a follow-up up to 10 years

PURPOSE

To investigate the effect of mid-buccal peri-implant keratinized mucosa width (KMW) ≥2 mm or peri-implant KMW >0 mm and <2 mm on the long-term outcomes of peri-implantitis reconstructive treatment.

MATERIALS AND METHODS

Twenty-nine patients (40 implants; mean follow-up: 9.2 ± 1.4 years) with at least one implant affected by peri-implantitis and surgically treated through a reconstructive procedure followed by a submerged healing were included. Patients were categorized according to their initial KMW: Group 1 (KMW ≥2 mm) and Group 2 (KMW >0 mm and <2 mm). Peri-implant clinical and radiographic parameters and a dedicated composite outcome were assessed at different follow-up visits during supportive peri-implant therapy for up to 10 years. Regression analyses were utilized to identify possible risk/predictive indicators for probing pocket depth (PPD) change and treatment success at the latest follow-up.

RESULTS

The mean PPD did not exhibit any statistical difference from the baseline to the latest follow-up between the groups at both patient and implant levels. Long-term treatment success was 46.6% (Group 1) and 42.6% (Group 2) at patient level, it was 42.8% (Group 1) and 33.3% (Group 2), respectively, at implant level (p > 0.05). Group 1 demonstrated significantly higher vertical defect depth reduction than Group 2 (p = 0.018). Presence of buccal bony wall and mean PPD at the baseline were found to be associated with mean PPD change, while KMW at 6 months following surgery was identified as the only significant indicator for treatment success (p < 0.05).

CONCLUSION

Implants with KMW ≥2 mm did not present significantly better long-term clinical outcomes following reconstructive therapy than those exhibiting KMW >0 mm and <2 mm. However, KMW values at the end of healing phase following a submerged approach had a significant impact on long-term treatment success.

Association of Peri-Implant Mucosa Dimensions With Emergence Profile Angles of the Implant Prosthesis

OBJECTIVES

The primary aim of this cross-sectional study was to investigate the association between prosthesis design and peri-implant mucosa dimensions and morphology. The secondary aim was to investigate associations between mucosal dimensions and the presence of mucositis.

MATERIALS AND METHODS

Forty-seven patients with 103 posterior bone level implants underwent clinical and radiographic examination, including cone beam computer tomography and intraoral optical scanning. Three-dimensional models for each implant and peri-implant mucosa were constructed. Vertical mucosa height (TH), horizontal mucosa width at implant platform (TW), and 1.5 mm coronal of the platform (TW1.5), as well as mucosal emergence angle (MEA), deep angle (DA), and total contour angle (TA) were measured at six sites for each implant.

RESULTS

There was a consistent correlation between peri-implant mucosa width and height (β = 0.217, p < 0.001), with the width consistently surpassing height by a factor of 1.4-2.1. All three angles (MEA, DA, TA) were negatively associated with mucosa height (p < 0.001), while DA was negatively associated with mucosa width (TW1.5) (p < 0.001, β = -0.02, 95% CI: -0.03, -0.01). There was a significant negative association between bleeding on probing (BoP) and mucosa width at platform (OR 0.903, 95% CI: 0.818-0.997, p = 0.043) and 1.5 coronal (OR 0.877, 95% CI: 0.778-0.989, p = 0.033). Implants with less than half sites positive for BoP (0-2/6) had significantly higher mucosa height (OR 3.51, 95% CI: 1.72-7.14, p = 0.001).

CONCLUSIONS

Prosthesis design can influence the dimensions of the peri-implant mucosa, with wider emergence profile angles associated with reduced peri-implant mucosa height. In particular, a wider deep angle is associated with reduced mucosa width in posterior sites. Reduced peri-implant mucosa height and width are associated with more signs of inflammation.

TRIAL REGISTRATION

Registered in Thai Clinical Trials Registry: http://www.thaiclinicaltrials.org/show/TCTR20220204002.

Progressive bone loss and bleeding on probing: A cohort study

AIM

To investigate whether a progressive marginal bone loss (PMBL) occurring beyond the initial bone remodeling (IBR) is linked with bleeding on probing.

MATERIALS AND METHODS

A total of 70 partially edentulous patients exhibiting 112 two-piece bone-level implants were included in this retrospective study. Panoramic radiographs were obtained after implant insertion (T0), after delivery of a final prosthetic restoration (T1) and subsequently during the 1-(T2), 5-(T3), 10-(T4), and 15-years (T5) follow-up visits. At each time point, radiographic marginal bone levels were assessed from the implant shoulder to the first bone-to-implant contact at mesial and distal aspects. The IBR was defined as a bone loss occurring up to prosthesis delivery, that is, from T0 to T1. The PMBL was defined as bone loss occurring after T1. At T2, T3, T4, and T5, the presence or absence of bleeding on probing (BOP) was recorded at four sites. A median regression with mixed models was performed to assess the difference of PMBL in PMBL + BOP+ and PBML + BOP- groups.

RESULTS

Over the mean implant functioning time of 4.44 ± 4.91 years, 38 (34%) implants showed no PBML, whereas 74 (66%) implants featured PMBL. Of these, 35 (47%) and 39 (53%) implants were assigned to the PMBL + BOP- and PMBL + BOP+ groups, respectively. The mean PMBL after 1, 5, 10, and 15 years were comparable between implants featuring PMBL with or without BOP. At 1 year, BOP intensity significantly correlated PMBL, with each increase in one BOP-positive site being associated with increase in PMBL by 0.55 mm (p = 0.038), whereas this association was not found at 5, 10, and 15 years. The IBR values in the no PBML, PMBL + BOP+, and PBML + BOP- groups were -0.24 ± 0.31, -0.41 ± 0.59, and -0.24 ± 0.33 mm, respectively, with no significant differences found among the groups.

CONCLUSION

Progressive bone loss at implant sites is not always linked with bleeding on probing.

Dental implant considerations in patients with systemic diseases: An updated comprehensive review

BACKGROUND

Various medical conditions and the drugs used to treat them have been shown to impede or complicate dental implant surgery. It is crucial to carefully monitor the medical status and potential post-operative complications of patients with systemic diseases, particularly elderly patients, to minimize the risk of health complications that may arise.

AIM

The purpose of this study was to review the existing evidence on the viability of dental implants in patients with systemic diseases and to provide practical recommendations to achieve the best possible results in the corresponding patient population.

METHODS

The information for our study was compiled using data from PubMed, Scopus, Web of Science and Google Scholar databases and searched separately for each systemic disease included in our work until October 2023. An additional manual search was also performed to increase the search sensitivity. Only English-language publications were included and assessed according to titles, abstracts and full texts.

RESULTS

In total, 6784 studies were found. After checking for duplicates and full-text availability, screening for the inclusion criteria and manually searching reference lists, 570 articles remained to be considered in this study.

CONCLUSION

In treating patients with systemic conditions, the cost-benefit analysis should consider the patient's quality of life and expected lifespan. The success of dental implants depends heavily on ensuring appropriate maintenance therapy, ideal oral hygiene standards, no smoking and avoiding other risk factors. Indications and contraindications for dental implants in cases of systemic diseases are yet to be more understood; broader and hardcore research needs to be done for a guideline foundation.

Local risk factors for one-year dental implant loss and late loss in 287 failed implants caused by peri-implantitis or infection after prosthesis loading: a retrospective study

The purpose of this paper was to retrospectively assess the local factors that are likely to be associated with the risks for one-year dental implant loss.A retrospective study was designed and implemented. The sample consisted of patients who underwent an implant loss or removal caused by peri-implantitis or infection after prosthesis loading. The chi-squared test and generalised estimating equations (GEE) were used to explore the potential risk factors for one-year implant loss. A total of 279 patients with 287 failed implants were enrolled in this study. Immediate implant placement exhibited a 3.373 (95% CI: 1.652 to 6.886) significantly increased risk to experience one-year implant loss than early and late implant placement (p = 0.001). In addition, implants loaded during a healing period fewer than two months after implant placement were at 18.139 (95% CI: 8.925 to 36.866) significantly higher risk of one-year implant loss when compared with those that loaded within more than two months after implant placement (p < 0.001). Smokers were 1.866 (OR = 1.866,95% CI: 0.993 to 3.510) times as high risk for one-year implant loss as non-smokers, but there were no significant statistical differences (p = 0.053). Immediate implant placement and early implant loading were considered risk factors for one-year implant loss.

Neurological emergency after dental implantat insertion - what now?

The following case report presents a 37-year old male patient who was referred for an emergency assessment due to suspected neurovascular damage of the inferior alveolar nerve following placement of two implants in the posterior left mandible. Immediate explantation for nerve decompression is essential combined with supportive analgesic and antiphlogistic medication. Furthermore, oral glucocorticoids were prescribed, starting with 20mg with a stepwise phasing out of the medication thereafter.

Impact of keratinized mucosa on implant-health related parameters: A 10-year prospective re-analysis study

AIM

To investigate whether the lack of keratinized mucosa (KM) affects peri-implant health after 10 years of loading.

MATERIALS AND METHODS

Data from 74 patients with 148 implants from two randomized controlled studies comparing different implant systems were included and analyzed. Clinical parameters including bleeding on probing (BOP), probing depth (PD), plaque index, marginal bone loss (MBL), and KM width (KMW) at buccal sites were collected at baseline (time of the final prosthesis insertion), 5-year and 10 years postloading. Multivariable logistic and linear regression models by means of a generalized estimated equation (GEE) were used to evaluate the influence of buccal KM on peri-implant clinical parameters; BOP, MBL, PD, and adjusted for implant type (one-piece or two-piece) and compliance.

RESULTS

A total of 35 (24.8%) implants were healthy, 67 (47.5%) had mucositis and 39 (27.6%) were affected by peri-implantitis. In absence of buccal KM (KM = 0 mm), 75% of the implants exhibited mucositis, while in the presence of KM (KMW >0 mm) 41.2% exhibited mucositis. Regarding peri-implantitis, the corresponding percentages were 20% (KM = 0 mm) and 26.7% (KM >0 mm). Unadjusted logistic regression showed that the presence of buccal KM tended to reduce the odds of showing BOP at buccal sites (OR: 0.28 [95% CI, 0.07 to 1.09], p = 0.06). The adjusted logistic regression model revealed that having buccal KM (OR: 0.21 [95% CI, 0.05 to 0.85], p = 0.02) and using two-piece implants (OR: 0.34 [95% CI, 0.15 to 0.75], p = 0.008) significantly reduced the odds of showing BOP. Adjusted linear regression by means of GEE showed that KM and two-piece implants were associated with reduced MBL and MBL changes (p < 0.05).

CONCLUSION

The lack of buccal KM appears to be linked with peri-implant parameters such as BOP and MBL, but the association is weak. The design of one-piece implants may account for their increased odds of exhibiting BOP.

The effect of one-time abutment placement on clinical and radiographic outcomes: A 5-year randomized clinical trial

OBJECTIVE

The aim of this study was to evaluate the long-term (5 years) clinical efficacy of the one-abutment one-time protocol (test) versus the standard of care by placing the definitive abutment on the day of the prosthetic delivery (control).

MATERIALS AND METHODS

In this study, 39 subjects with 60 implants were randomly allocated to either the test or the control group. Changes in the radiographic interproximal bone levels (DIB), modified sulcus bleeding index, probing depth, modified plaque index, papilla fill (Jemt score), incidence of peri-implantitis and peri-implant mucositis as well as patient-reported outcomes measures (PROMs) were collected and compared at 1, 3 and 5 years.

RESULTS

At 5 years, the control group showed a greater, although not statistically significant, change in mean DIB values (0.97 mm vs. 0.53 mm). Regarding the other clinical parameters evaluated, no statistically significant differences were observed between groups at any time point. At 5 years, 51% of the implants presented peri-implant mucositis (25.5% in the control and 23.5% in the test), and only one implant in the test group developed peri-implantitis.

CONCLUSIONS

The connection and disconnection of healing abutments during the healing period was not associated with higher long-term bone loss. Clinical outcomes and PROMs were similar between groups.

Peri-implant epidermoid cyst: A case report and literature analysis

BACKGROUND

A peri-implant cystic lesion is a rare finding, and to date most investigators have considered that its pathogenesis is caused by trauma and infection related to dental implantation. However, the pathogenesis of these cysts remains unclear and is recognized to have multifactorial origins.

CASE PRESENTATION

In February 2021, a 75-year-old male patient underwent implant restoration due to mobility of the left maxillary central incisor. The implant achieved good osseointegration and was successfully restored. However, in March 2023, the patient sought treatment due to mobility of the dental implant. Clinical examination showed that the implant had loosened in three directions (vertical, mesial-distal, and labial-lingual), and the peri-implant mucosa was slightly red and swollen. Radiographic examination (cone beam computed tomography) showed a large radiolucent area with clear boundaries involving the cervical and middle portions of the dental implant, and white bone lines were observed at the edge of the low-density shadow. Intraoperatively, we removed the patient's implant, performed a complete debridement, and conducted bone augmentation surgery in the area of bone defect. Postoperatively, the patient recovered well. The final histopathological result confirmed an epidermoid cyst.

CONCLUSIONS

Peri-implant epidermoid cyst is a rare complication that affects the long-term outcome of implant therapy. This case serves as a warning to clinicians to avoid involving epithelial tissue in the implant site during implant surgery, in order to prevent the potential occurrence of a peri-implant epidermoid cyst, thereby creating better conditions for the patient's recovery and the long-term efficacy of the implant.

Maxillary sinus opacification after surgery in asymptomatic patients: Transient swelling of the sinus mucosa or graft dispersion into the maxillary sinus. A radiographic report of three cases after a follow-up period of at least 5 years

Maxillary sinus grafting is a predictable regenerative technique to facilitate maxillary posterior implant placement when there is insufficient vertical bone height inferior to the maxillary sinuses to allow placement of implants of adequate dimensions. It enables an increase in vertical bone height, which makes implant placement easier. Maxillary sinus mucosal membrane perforation is one of the most common intraoperative complications during maxillary sinus grafting and may result in extrusion of graft material into the sinus. When this occurs, the mucociliary function of the maxillary sinus may expel the extruded graft material through its natural ostium, though graft particles may remain in the sinus or possibly occlude the natural ostium. After grafting, transient maxillary sinus mucosal oedema may occur. A postoperative CBCT scan may reveal varying degrees of sinus opacification, namely partial, subtotal or total. Although it is always possible to identify graft material, which may enter the sinus as a result of membrane perforation that might not even be visible to the implantologist during the surgical procedure, it is challenging to assess whether sinus opacification is due to mucosal thickening or mucus accumulation. The aim of the present case series was to offer a pragmatic approach to managing asymptomatic patients whose CBCT scans demonstrated partial, subtotal or total maxillary sinus opacification with bone graft particles that seemed to have been extruded into the sinus.

The safety of maxillary sinus floor elevation and the accuracy of implant placement using dynamic navigation

OBJECTIVE

To date, it remains a challenge to conduct maxillary sinus floor elevation (MSFE) owing to heterogeneity of anatomical structures and limited operative visibility of the maxillary sinus. The aim of this study is to investigate the safety of MSFE and the accuracy of implant placement using dynamic navigation.

METHODS

Forty-two implants were placed in thirty-five patients requiring implantation in posterior maxilla with dynamic navigation. They were assigned to either lateral window sinus floor elevation (LWSFE) group (n = 22) or transcrestal sinus floor elevation (TSFE) group (n = 20) according to the residual alveolar bone height (RBH). Platform deviation, apex deviation and angular deviation between actual and planned implant placement were measured in precision evaluation software. Three deviations of two groups were compared via SPSS 22.0 software.

RESULTS

Neither accidental bleeding nor perforation of Schneiderian membrane occurred in any patients. The actual window position of LWSFE was consistent with the preoperative design. There were no significant differences in platform, apex and angular deviations between the two groups (P > 0.05).

CONCLUSION

In this study the dynamic navigation harvested clinically acceptable safety of MSFE and accuracy for implant placement in posterior maxillary region. The dynamic navigation would provide the clinician with assistance in achieving precise preoperative planning and reducing complications in surgical procedures. The granular bone grafts used in the LWSFE did not significantly affection on the accuracy of the simultaneous implant placement under the guidance of dynamic navigation.

Immediate repair of bony defects in the posterior mandibular region following removal of a fractured implant: a feasible treatment?

The aim of this study was to assess whether immediate bone reconstruction after removal of a fractured dental implant in the posterior mandible provides a sound base for implant replacement, with a favourable treatment outcome and high patient satisfaction. Eight consecutive patients with a fractured implant neck were included. The implant was removed via osteotomy, following which the site was immediately repaired with a mixture of autogenous bone and bone substitute. After a 4-month healing period, sufficient bone and favourable soft tissue conditions were present, allowing implant placement with adequate primary stability. After a further 3 months, the implants were restored with an all-ceramic restoration. Patient satisfaction, the aesthetic outcome, complications, and postoperative morbidity were assessed using standardized clinical and radiographic examinations up to 5 years after crown placement. No implant failures were observed during the follow-up. Plaque accumulation, the presence of calculus, bleeding tendency, and peri-implant inflammation indices were low, indicating healthy peri-implant conditions. The mean marginal bone level change at the 5-year follow-up was - 0.17 ± 0.46 mm. All patients reported a high level of satisfaction (mean overall score 9.3 ± 0.5). In conclusion, immediate reconstruction of the hard tissue after removal of a fractured dental implant is a viable treatment option. This approach facilitates rehabilitation, reduces morbidity, and leads to favourable aesthetic outcomes.

Clinical outcomes and risk factor analysis of dental implants inserted with lateral maxillary sinus floor augmentation: A 3- to 8-year retrospective study

AIM

To evaluate the 3- to 8-year outcomes of dental implants placed with lateral sinus floor augmentation (LSFA) and to identify factors affecting implant survival.

MATERIALS AND METHODS

This retrospective study was performed by screening all implants placed with LSFA procedures, which were conducted between January 2012 and December 2016. Subantral bone gain (SABG) and apical bone height (ABH) were assessed using panoramic radiographs. The cumulative survival rate of implants was analysed using life-table analysis and Kaplan-Meier survival curves. The influential risk factors affecting survival were assessed using univariate log-rank tests and multivariable mixture cure rate model. Implant complications were recorded.

RESULTS

Based on the established criteria, a total of 449 patients (760 implants) were included in this study. In the 3- to 8-year follow-up (mean ± SD, 5.81 ± 1.33 years), 15 implants in 14 patients failed, with a CRS of 96.81% on an implant basis and 95.07% on a patient basis. A history of periodontitis and poor compliance with supportive periodontal treatment was associated with a significantly higher risk of implant failure at both implant and patient levels. Significant decreases in ABH occurred during each yearly interval except for 3 years. A similar trend has been observed for SABG at 1, 2, 6 and 8 years. The total complication rate was 31.84% on implant basis, with peri-implant mucositis (21.58%) being the most frequent biologic complication and porcelain cracking (5.00%) being the most common technical complication.

CONCLUSIONS

Implant with LSFA is a reliable treatment option in atrophic maxilla. A history of periodontitis without regular supportive periodontal treatment was identified as a predictor for implant failure. Slight but significant shrinkage of vertically augmented bone can be observed after implant placement.

Radiographic evaluation of the distance between the restoration margin and the alveolar bone crest in dental implant patients: A retrospective study

OBJECTIVES

The recently introduced Implant Disease Risk Assessment (IDRA) identifies a restoration margin-alveolar bone crest (RM-AC) distance of less than 1.5 mm as a key risk factor for peri‑implant disease among eight major risk factors. This study evaluated the impact of the RM-AC distance on marginal bone loss (MBL) through radiographic analysis.

METHODS

This retrospective cross-sectional study included 77 partially edentulous patients (39 females and 38 males, aged 22 to 76 years) with 202 platform-switched conical connection implants, cement-retained, implant-supported fixed restorations, and bone-level implants placed between 2016 and 2021. Dental implants were followed for least 6 to 36 months at follow up functional loading. Study participants were categorized into Group A (RM-AC distance ≤ 1.5 mm, n = 69) and Group B (RM-AC distance > 1.5 mm, n = 133). Twelve patients in Group B and five patients in Group A had no history of periodontal disease. The MBL was measured radiographically from the most coronal point of the implant shoulder to the alveolar bone, and the RM-AC distance was measured from the restoration margin to the alveolar crest. Multinomial logistic regression analysis was used for statistical evaluation.

RESULTS

The incidence of MBL in Group A was statistically significant and 3.42 times higher than that in Group B. The rate of MBL in periodontitis Stage 4 was found to be 26.31 times higher than that in periodontitis Stage 2. The incidence of MBL was 6.097 and 5.02 times higher with increasing implant diameter and length, respectively.

CONCLUSION

This study conclusively demonstrates that RM-AC distance ≤ 1.5 significantly increases the risk of MBL, particularly in patients with a history of periodontal disease.

CLINICAL SIGNIFICANCE

This study highlights the critical role of maintaining an RM-AC distance greater than 1.5 mm in the prevention of MBL, particularly in patients with a history of periodontal disease. Since implant diameter and length have a significant impact on the risk of MBL, it emphasizes that implant demographics should also be carefully evaluated.

Radiographic bone loss around dental implants: a large-cohort, long-term follow-up revealing prevalence and predictive factors

OBJECTIVE

This retrospective study analyzed radiographic bone levels of 10,871 dental implants in a cohort of 4,247 patients over a 22-year period. The objectives of the study were to assess and explore risk factors associated with the radiographic bone level of dental implants.

METHOD AND MATERIALS

A longitudinal observational cohort study based on data collected from 1995 to 2019 was conducted on implants placed by a single periodontist. Inclusion criteria included both partially and fully edentulous sites. Exclusion criteria were patients who were considered ASA 3 or greater. Information on medical and dental status prior to implant placement such as diabetes and smoking were included in the analysis. Implant factors such as the implant characteristics (length and diameter) and surgical site were recorded. The outcome assessed was the prevalence of bone loss around implants and any associative factors related to the bone loss.

RESULTS

Overall, dental implants lost an average of 0.05 ± 0.38 mm of bone 2 to 3 years after placement and 0.21 ± 0.64 mm 8 years after placement. The soft tissue condition was evaluated using the Implant Mucosal Index (IMI), and bone loss around dental implants was significantly higher when bleeding on probing was multi-point and moderate, multi-point and profuse, and when infection with suppuration was recorded. The mean difference in bone level between smokers and nonsmokers was 0.26 mm (P < .01) over a 4-year period. A mean difference of 0.10 mm (P = .04) in bone loss over 4 years was found between those with an autoimmune disease compared to those without. The diameter of the implant and immediate loading of the dental implant did not influence the radiographic bone levels over time.

CONCLUSIONS

This large dataset of dental implants highlights predictive risk factors for bone loss around dental implants and the impact these risk factors have on the implant bone level. Consideration of these risk factors by both the dental team and the patient prior to dental implant placement will promote success of the treatment.

Soft Tissue Response and Determination of Underlying Risk Drivers for Recession and Mucositis after AMSJI Implantation in the Maxilla

PURPOSE

To evaluate the soft tissue response to the placement of additively manufactured subperiosteal jaw implants (AMSJI) in the severely atrophic maxilla and to identify possible risk factors for soft tissue breakdown.

MATERIALS AND METHODS

An international multicenter study was conducted, and 15 men (mean age: 64.62 years; SD: ± 6.75) and 25 women (mean age: 65.24 years; SD: ± 6.77) with advanced maxillary jaw resorption (Cawood and Howell Class V or more) were included in this study. General patient data were collected, and all subjects were clinically examined. Inclusion criteria were patients who underwent bilateral AMSJI placement in the maxilla at least 1 year prior. Exclusion criteria were patients who did not have patient, surgeon, or dentist consent to participate in the study before their inclusion.

RESULTS

A total of 40 patients were enrolled, with a mean follow-up period of 917 days (SD: ± 306.89 days). Primary implant stability was achieved postoperatively in all cases, and all implants were loaded with a final prosthesis. At the time of the study, only 1 patient showed mobility (> 1 mm) of the bilateral AMSJI. Due to mucosal recession, exposure of the framework was seen in 26 patients (65%) and was mainly in the left (21.43% of 26) and right (18.57% of 26) midlateral region. A thin biotype and the presence of mucositis were found to be risk factors (P < .05). Although not significant, smokers had a risk of developing a recession that was nearly seven times (odds ratio: 6.88; P = .08) greater than that of nonsmokers.

CONCLUSIONS

Twenty-six (65%) patients presented with a recession in one (or more) of the seven regions after oral rehabilitation with bilateral AMSJI placement. Several risk drivers were evaluated. The collapse of soft tissues around the AMSJI that led to caudal exposure of the arms was correlated with a thin biotype and the presence of mucositis.

How do the dimensions of peri-implant mucosa affect marginal bone loss in equicrestal and subcrestal position of implants? A 1-year clinical trial

INTRODUCTION

There is evidence that the apico-coronal implant position and the mucosal phenotype can affect the extent of peri-implant bone loss. This clinical trial analyzes the bone remodeling and marginal bone loss that occur around conical-connection implants placed equicrestally and subcrestally, assessing the effect of the peri-implant soft-tissue phenotype.

METHODS

Fifty-one patients received 56 implants of distinct diameters (3.5 mm Ø n = 6; 4.3 mm Ø n = 41; 5 mm Ø n = 9) in the posterior part of the maxilla or mandible. The implants were placed equicrestally, 1 mm subcrestally and >1 mm subcrestally, depending on the initial supracrestal tissue height (STH). After 3 months of non-submerged healing, single metal-ceramic screw-retained implant-supported crowns were placed. Longitudinal measurements of STH, mucosal thickness and keratinized mucosa width (KMW) were made at the time of implant placement (T0), crown placement (T1), and after 3 (T2) and 6 months (T3) of prosthetic loading. At each of these points, a radiographic evaluation of bone remodeling and marginal bone loss was also performed.

RESULTS

STH was significantly greater for implants placed >1 mm subcrestally than for those placed 1 mm subcrestally. After 12 months of follow-up, a very significant (p < 0.001) loss of KMW was observed, in addition to a marginal bone loss of 0.08 ± 0.1, 0.15 ± 0.2, and 0.14 ± 0.2 mm in the groups placed equicrestally, 1 mm subcrestally and >1 mm subcrestally, respectively. After the multiple linear regression, marginal bone loss was found to depend primarily on KMW (β = -0.43), while also being affected by STH (β = 0.32) and implant diameter (β = -0.28).

CONCLUSIONS

Marginal bone loss may be influenced by the position with respect to the bone crest, as well as the KMW, STH, and implant diameter. However, more well-controlled studies are needed to verify these above-mentioned findings with different implant designs and connections.

Clinical outcomes of 3-5 years follow-up of immediate implant placement in posterior teeth: a prospective study

BACKGROUND

Immediate implant placement in posterior teeth has become popular in recent years. However, only a few studies focused on evaluating the long-term success of immediate implant placement.

PURPOSE

To analyze the clinical outcomes of immediate implant placement in the posterior region with conventional loading with 3-5 years follow-up following the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference.

METHOD

The study was done in 25 bone-level implants (Straumann® SLActive® bone level tapered implant, Straumann®, Basel, Switzerland) in 19 patients who underwent immediate implant placement in a posterior tooth with conventional loading with 3-5 years follow-up. The overall success and survival of these placements were evaluated following the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference using chart records, clinical examination, radiographic evaluation, and outcomes measurement. Patient satisfaction was evaluated by using a numeric rating scale. The biological and technical status, modified Pink Esthetic Score (mPES), complications, and marginal bone change were also evaluated. The analysis was done using SPSS version 21 (SPSS Inc., Chicago, IL, USA). The data were analyzed using a paired samples t-test.

RESULTS

It was found that 24 out of the 25 (96%) dental implants survived for an average of 57 ± 8.07 months. All of the 24 surviving dental implants were considered an operational success. The average mPES was 9.75 ± 0.44. The major prosthetic complications seen were: (1) proximal contact loss (41.67%), (2) loosening of the screw (8.33%), and (3) cement debonding (4.17%).

CONCLUSIONS

Immediate implant placement in a posterior tooth with conventional loading yields a predictable result with some complications. The most prominent complications were proximal contact loss, followed by loosening of the screw and cement debonding. The implant survival rate was 96% at a mean time follow-up of 4 years and 9 months.

Management of bleeding during dental implant surgery using a novel implant with an abbreviated drilling protocol: A clinical report

Coagulopathy is a well-recognized complication in dental surgery in patients who use oral anticoagulants or some dietary supplements. Proper pre-operative diagnosis, medical consultation, timely management, and conservative treatment can decrease the incidence of such complications. Management of bleeding during dental implant surgery commonly involves conventional methods such as discontinuation of anticoagulant use, compression, styptics, and local anesthetic administration containing vasoconstrictors. This clinical report describes the successful management of a patient with a history of coagulopathy who was rehabilitated with complete arch fixed implant-supported prostheses with immediate loading. A novel implant design with a significantly abbreviated single drill protocol for osteotomy preparation was used in an outpatient setting. The novel protocol successfully decreased the overall bleeding and significantly reduced the intraoperative time for the surgical procedure. Additional considerations related to the novel implant design and osteotomy protocol, supplementary applications, and advantages of the protocol are presented in this article.

Correlation between intraosseous thermal change and drilling impulse data during osteotomy within autonomous dental implant robotic system: An in vitro study

OBJECTIVES

This study aims at examining the correlation of intraosseous temperature change with drilling impulse data during osteotomy and establishing real-time temperature prediction models.

MATERIALS AND METHODS

A combination of in vitro bovine rib model and Autonomous Dental Implant Robotic System (ADIR) was set up, in which intraosseous temperature and drilling impulse data were measured using an infrared camera and a six-axis force/torque sensor respectively. A total of 800 drills with different parameters (e.g., drill diameter, drill wear, drilling speed, and thickness of cortical bone) were experimented, along with an independent test set of 200 drills. Pearson correlation analysis was done for linear relationship. Four machining learning (ML) algorithms (e.g., support vector regression [SVR], ridge regression [RR], extreme gradient boosting [XGboost], and artificial neural network [ANN]) were run for building prediction models.

RESULTS

By incorporating different parameters, it was found that lower drilling speed, smaller drill diameter, more severe wear, and thicker cortical bone were associated with higher intraosseous temperature changes and longer time exposure and were accompanied with alterations in drilling impulse data. Pearson correlation analysis further identified highly linear correlation between drilling impulse data and thermal changes. Finally, four ML prediction models were established, among which XGboost model showed the best performance with the minimum error measurements in test set.

CONCLUSION

The proof-of-concept study highlighted close correlation of drilling impulse data with intraosseous temperature change during osteotomy. The ML prediction models may inspire future improvement on prevention of thermal bone injury and intelligent design of robot-assisted implant surgery.