Prospective observational cohort study of the change of the marginal bone crest in relation to the prosthetic abutment height and the peri-implant vertical mucosal thickness at implants positioned subcrestally.

AIM: To evaluate the influence on peri-implant crestal bone loss exerted by the vertical mucosal thickness and the abutment height over 12 months after placement of the restoration on subcrestal implants with change of platform, using a restoration abutment platform smaller than the implant platform. MATERIALS AND METHODS: A total of 99 implants were rehabilitated in the maxillary and mandibular posterior regions. A total of 22 implants were rehabilitated in the maxilla and 77 implants in the mandible, using digitally designed customized abutments with Atlantis weborder software, from the commercial house Dentsply Sirona (Dentsply Sirona S.A., Barcelona, Spain), version 4.6.5, adapting the height to the vertical thickness of the mucosa. Clinical and radiographic monitoring begins during the surgical procedure of placement of the implant and ends 12 months afterwards. Crestal bone loss was evaluated through the Carestream® CS8100 3D radiographic equipment. RESULTS: In all cases, the greatest loss of marginal bone occurred between the day of surgery (Tx) and placement of the rehabilitation (To). The average bone loss between both times was greater when the abutment height and vertical mucosal thickness did not exceed 3 mm. Subsequently, bone loss slowed and stabilized at 12 months. CONCLUSIONS: The minimum abutment height and the vertical mucosal thickness are factors to take into account when minimizing peri-implant marginal bone loss, the abutment height having the greatest importance according to the clinical data obtained.

Association of Peri-Implant Keratinized Mucosa Width and Mucosal Thickness with Early Bone Loss: A Cross-Sectional Study.

Objective: The objective of this study was to evaluate the effects of keratinized mucosa width (KMW) and mucosal thickness (MT) around dental implants on marginal bone loss (MBL). The evaluation was performed one year after loading by comparing clinical, radiographic, and biochemical parameters. Methods: The study included 87 implants in 87 patients undergoing regular follow-ups without hard or soft tissue augmentation one year after loading. Clinical measurements included plaque index (PI), gingival index (GI), bleeding on probing (BoP), probing depth (PD), KMW, and MT. MBL was assessed with periapical radiography. The peri-implant crevicular fluid (PICF) was analyzed for tumor necrosis factor-alpha (TNF-α), receptor activator of nuclear factor-kB ligand (RANKL), osteoprotegerin (OPG), and microRNA-27a. Results: The MBL of implants with thin MT (<2 mm) was higher than that of implants with thick MT (≥2 mm) (p < 0.05). A significant negative correlation (r: -0.217) was established between MT and MBL. No significant association was found between KMW and MBL (p > 0.05). No significant associations was found between KMW and MT with TNF-α, RANKL, OPG and RANKL/OPG (p > 0.05), with the exception of increased microRNA-27a levels in implants with KMW ≥ 2 mm (p < 0.05). Conclusions: Implants with a thick MT had a lower MBL. There may be an association between adequate KMW and high miRNA-27a levels. The relationship between MBL and miRNA-27a remains unclear.

Changes in the Maxillary Sinus Membrane Thickness and Sinus Health Following Lateral Sinus Floor Elevation: Comparing Preoperative Mucosal Thicknesses of Less than and Greater than 5 Millimeters.

PURPOSE: To investigate the effect of lateral sinus floor elevation (LSFE) on sinus membrane (SM) thickness and sinus health in mucosa thickness less and more than 5 mm. MATERIALS AND METHODS: LSFE was performed in a prospective controlled clinical trial on two groups with less than and more than 5 mm (group A & B) SM thickness and followed for 6 months. Using preoperative and 6-month postoperative CBCT and clinical evaluation, SM thickness changes (primary outcome variable), sinus health, augmented bone height, and length (augmentation adequacy), membrane-related variables, and operation time were measured. RESULTS: Forty unilateral sinus augmentations (A:20, B:20) with simultaneous installation of 52 fixtures were performed on 40 subjects (72.5% males, mean age of 48.8±7.6). The mean preoperative and 6- month SM thicknesses in group A and group B were 1.4±0.9 and 1.3±0.6 mm, and 6.8±1.0 and 3.4±1.7 mm, respectively. The mean postoperative SM thickness significantly decreased (P<0.001) only in group B. The mean SM thickness changes also revealed a noticeable difference between the two groups (P<0.001). Augmentation adequacy and membrane perforation rate were similar in both groups. Clinical and radiographic rhinosinusitis was not detected in any of the patients. Bleeding during separation and resistance to elevation in group B were significantly higher than in group A (P=0.003, P=0.001). Surgical time in group B (12.08 ± 8.26 minutes) was longer than in group A (8.64 ± 3.70 minutes), without reaching a significant level (P=0.097). CONCLUSIONS: LSFE in thickened mucosa (≤10 mm) and thinner mucosa (≤5 mm) does not cause abnormal changes in the sinus membrane and sinus health. LSFE in thickened mucosa results in adequate sinus augmentation. Thickened SM also shows a significant thickness reduction. The thickened membrane does not appear to be a contraindication to SFE.

Evaluation of the treatment effect on sinus elevation and implant restoration in cases with odontogenic maxillary sinusitis after tooth extraction / 口腔疾病防治

Objective@#To investigate the clinical effects of sinus elevation surgery and implant restorationdue to insufficient bone massafter tooth extraction in patients with odontogenic maxillary sinusitis (OMS) and to provide a reference for use in clinical practice.@*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. Forty-five teeth were extracted from patients with OMS in the maxillary posterior area (the study group). Sinus elevation and implantation were performed due to insufficient bone height in the implant area 6-8 months after tooth extraction in the study group. Forty-eight teeth were extracted from patients without "OMS" in the maxillary posterior area (the control group), and sinus elevation and implantation were performed due to insufficient bone height in the implant area 6-8 months after tooth extraction inthe control group. In the study group, 13 cases of discontinuous maxillary sinus floor bone and residual alveolar bone height of the maxillary sinus floor less than 4 mm were addressed with lateral wall sinus elevation, and the other 32 cases were addressed with crest-approach sinus elevation. In the control group, 8 cases of residual alveolar bone height less than 4 mm in the maxillary sinus floor were addressed with lateral wall sinus,and the other 40 cases were addressed with crest approach sinus elevation. Restorations were placed 6 to 8 months after surgery. The patients were followed up 21 days, 3 months, and 8 months after implantation and every 6 months after the placement of the restorations. The sinus bone gain (SBG), apical bone height (ABL) and marginal bone loss (MBL) were statistically analyzed 24 months after the restoration.@*Results@#The average preoperative mucosal thickness in the 45 patients in the study group was (1.556 ± 0.693) mm, which was significantly larger than that in the control group (1.229 ± 0.425) mm (P<0.001). There were no perforations in either group. Twenty-four months after restoration, there was no significant difference in the SBG, ABH or MBL between the two groups (P>0.05).@*Conclusion@#After the extraction of teeth from patients with OMS, the inflammation of the maxillary sinus decreased, and the bone height and density in the edentulous area were restored to a certain degree. The effects of sinus floor lifting surgery and implant restoration do not differ between patients with and without OMS.

Morphological Comparison of Residual Ridge in Impression for Removable Partial Denture between Digital and Conventional Techniques: A Preliminary In-Vivo Study.

Although digital impression using an intraoral scanner (IOS) has been applied for removable partial denture (RPD) fabrication, it is still unclear how the morphology of a residual ridge recorded by digital impression would differ from that recorded by conventional impression. This in vivo study investigated the morphological difference in the recorded residual ridge between digital and conventional impressions. Vertical and horizontal displacements (VD and HD) in residual ridges recorded by digital and conventional impressions were assessed in 22 participants (15 female; mean age 78.2 years) based on the morphology of the tissue surface of in-use RPD. Additionally, the mucosal thickness of the residual ridge was recorded using an ultrasound diagnostic device. VD and HD were compared using the Wilcoxon signed-rank test, and the correlation of mucosal thickness with VD and HD was analyzed using Spearman's ρ. The VD of digital impression was significantly greater than that of a conventional impression (p = 0.031), while no significant difference was found in HD (p = 0.322). Meanwhile, the mucosal thickness showed no significant correlation with the recorded morphology of the residual ridge, regardless of the impression techniques. It was concluded that the digital impression would result in a greater displacement in the height of the residual ridge from the morphology of in-use RPD than the conventional impression.

Assessment of palatal mucosal thickness and location of the greater palatine foramen using cone-beam computed tomography: a retrospective study.

OBJECTIVES: This study aimed to measure the palatal mucosal thickness and examine the location of the greater palatine foramen using cone-beam computerized tomography (CBCT). METHODS: In this study, cone-beam computed tomography (CBCT) images of the maxillary posterior region of 120 subjects were evaluated. The palatal mucosal thickness (PMT), palatal width and depth, and location of the greater palatine foramen (GPF) were determined on CBCT. The differences in the palatal mucosal thickness according to gender and palatal width/palatal depth were analyzed. The location of the GPF related to the maxillary molars was noted. RESULTS: The mean palatal mucosal thicknesses from the canine to the second molar teeth were 3.66, 3.90, 4.06, 3.76, and 3.92 mm, respectively. The mean PMT at the second premolar was statistically thicker than at other regions (p < 0,001). There was no relationship between PMT and gender. However, the palatal depth and width of the males were greater than females. (p = 0.004 and p = 0.014, respectively) PMT in the low palatal vault group had statistically higher compared to the high palatal vault group. (p = 0.023) Greater palatine foramen was mostly observed between second and third molar teeth. (48%). CONCLUSIONS: According to our results, first and second premolar regions can be preferable in soft tissue grafting procedures for safe and successful treatment outcomes. The measurement of the thickness of the palatal mucosa and the evaluation of the greater palatine foramen location before the surgical procedures are essential steps to harvest from the ideal donor site and to achieve optimal surgical outcomes.

Proximity of healthy posterior teeth to the maxillary sinus floor in relation to mucosal thickening: a CBCT study.

OBJECTIVES: To evaluate the relationship between proximity of the root apices of healthy maxillary posterior teeth to the maxillary sinus floor (MSF) and mucosal thickening (MT) of the MSF using cone beam computed tomography (CBCT). METHODS: Eighty-four CBCT images obtained from the patients, aged between 20 and 70 years with healthy and fully dentate maxillary posterior sextants, were included. The anatomical relationship between root apices of maxillary posterior teeth and MSF, was evaluated: (Type 1: no contact, Type 2: at least one root apex in contact, Type 3: at least one root apex protruding into MSF). Besides, MT of the MSF was measured from the thickest region. The patients were categorized into two groups based on the absence (≤ 2 mm) or the presence (2 < mm) of MT. Statistical significance was accepted at p < 0.05. RESULTS: Intraexaminer consistency demonstrated an excellent agreement (p < 0.05). The prevalence of Type 1, 2, and 3 proximity were found as 26 (15.5%), 61 (36.3%), and 81 (48.2%); respectively. Overall, 62 (36.9%) maxillary sinuses demonstrated MT (2 < mm, mean: 8.6 ± 7.5 mm). The prevalence and mean values of MT (2 < mm) were not found to be statistically significantly different in terms of sex and proximity types (p > 0.05). Logistic regression analysis results were not found to be statistically significant (p > 0.05). CONCLUSION: The proximity of healthy maxillary posterior teeth to the MSF was not found to be a contributing factor for the MT of the MSF. Further studies with larger samples, taking the other factors causing MT into consideration, are needed.

Comparison of biological and mechanical properties of different paranasal sinus mucosa in goat.

OBJECTIVE: The present study was designed to explore endurable pressure intensity of different paranasal sinus mucosa in goats. METHOD: Mucosa commonly involved in maxillary sinus augmentation, including mucosa from maxillary sinus crest, maxillary sinus floor, and frontal sinus, were harvested in a computed tomography-guided manner. The obtained mucosa was then sectioned into square and irregular ones for maximum endurable pressure intensity determination and morphological observation, respectively. RESULTS: Thickness of paranasal sinus mucosa, as determined under morphological staining by an optical microscope with a graduated eyepiece, were calculated. And the results showed that the average thickness of maxillary sinus crest mucosa, floor mucosa, and frontal sinus mucosa in goats were 410.03 ± 65.97 µm, 461.33 ± 91.37 µm and 216.90 ± 46.47 µm, respectively. Significant differences between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus were observed (P < 0.05). Maximum endurable pressure intensity was determined by utilizing a self-made clamp device and the results revealed maximum endurable pressure intensity of maxillary sinus crest mucosa, floor mucosa and frontal sinus mucosa in goats were 260.08 ± 80.12Kpa, 306.90 ± 94.37Kpa and 121.72 ± 31.72Kpa, respectively. Also, a statistically significant difference was observed when comparing the endurable pressure intensity between maxillary sinus crest and frontal sinus, maxillary sinus floor, and frontal sinus (P < 0.05). Further correlation analysis also revealed a positive correlation between the thickness of mucosa of the maxillary sinus and frontal sinus and maximum endurable pressure intensity (P < 0.05). CONCLUSION: Mucosal thickness and maximum endurable pressure intensity of maxillary sinus crest and floor were larger than that of frontal sinus mucosa and a positive correlation between the thickness of mucosa and endurable pressure intensity was observed. Our results thus might provide an experimental basis and guidance for mucosa-related problems involved maxillary sinus augmentation.

Odontogenic Maxillary Sinusopathies: a Radiological Classification.

Purpose: Before implant surgery, a preoperative radiological evaluation is recommended for recognizing maxillary inflammatory conditions. In order to avoid a failure of the dental procedure and prevent medical-legal consequences, it is necessary to treat patients suffering of maxillary sinus pathologies. The classification proposed in our study aims to standardize the reference values for mucosal thickening and to verify their association with the odontogenic or disventilatory causes of sinus pathology. Methods: The maximum mucosal thickness was measured at the level of the maxillary sinus floor: mucosal thickness was present when greater than 1 mm and was classified according to its extension within the sinus cavity. Results: Imaging data of 270 adult patients were included, performed for dental diagnosis and treatment planning, and they were divided into four main classes: Class I (85 pt.), mucosal thickness lesser than 2 mm, not pathological. Class II A (52 pt.), mucosal thickness between 2 and 5 mm, localized to the maxillary sinus floor: it is still considered non-pathological, and a "wait-and-see" approach is recommended. Class II B (46 pt.), mucosal thickness greater than 5 mm but localized at sinus floor: pathological mucosa with odontogenic etiology, requiring dental treatment. Class III A (39 pt.), mucosa thicker than 5 mm and concentric, most likely due to sinus ventilation disfunction: it requires maxillary antrostomy. Class III B (30 pt.), sinonasal manifestations such as nasal polyposis, retention cysts, mucocele, dental foreign body: pathological mucosa to be treated with ESS. Class IV (12 pt.), oroantral fistula: nasal endoscopic or oral approach. Conclusions: Our classification intends to suggest the better therapeutic option, in case of sinus pathology, according to the entity and pathogenesis of the mucosal thickening, in order to reduce complication and failure rate of dental surgery.

Histologic composition of marginal mucosal tissue augmented by a resorbable volume-stable collagen matrix in soft tissue thickening procedures in humans: a morphometric observational study.

AIM: This study aims to examine the composition of lining and masticatory mucosa at the pre- and post-soft tissue augmentation procedures with a volume-stable cross-linking collagen matrix (VCMX) in humans. MATERIALS AND METHODS: In 12 patients, single implant sites were augmented with a VCMX. Biopsies were obtained including masticatory (MM) and lining (LM) mucosa before augmentation and at 12 weeks post-augmentation procedures. Rete pegs density (RPD), length (RPL), and blood vessel density (BVD) were histomorphometrically analyzed at both time points. Picrosirius red staining under polarized light microscopy was used to evaluate collagen fiber organization. The effects of time and tissue type were evaluated by ANOVA with repeated measures. RESULTS: Both MM and LM areas demonstrated an increase in mean RPL following augmentation, 382.6 µm ± 95.1 vs. 290.5 µm ± 79.3 and 335.6 µm ± 94.2 vs. 292.9 µm ± 77.0, respectively (p < .05). There was a significant difference in the numbers of RP per 1 mm length (RPD) between the MM (9.2 ± 1.7) and LM (6.1 ± 2.8) mucosa but not between the pre- and post-VCMX augmentation time points. The mean BVD in the LM was greater than in the MM (5.5 ± 2.4 and 6.3 ± 2.4 vs. 3.4 ± 3.3 and 3.7 ± 1.8, respectively, p < .05) but not between time points. The collagen fiber arrangements pre- and post-augmentation were not significantly different. CONCLUSION: Augmentation with VCMX did not alter the composition of lining and masticatory mucosa at implant sites. CLINICAL RELEVANCE: A thick soft tissue phenotype around the implant neck is an important factor to maintain peri-implant health. A non-autogenous cross-linking collagen matrix is proposed as an alternate graft substitute in soft tissue augmentation procedures in order to improve implant soft tissue phenotype.

CBCT study on the safe location of palatal microscrew implant anchorage nail between maxillary first and second molars / 口腔疾病防治

Objective@#Conebeam CT (CBCT) was used to measure the palatine between the maxillary first and second molars. The proximal and distal palatal widths of the maxillary first and second molar and the palatal mucosal thickness and bone tissue thickness when microscrew implant anchorage nail were implanted at different angles provided a reference for the clinical selection of microscrew implant placement.@* Methods@#The image data of 90 adult patients were selected as the research object, and the jaw bone was reconstructed by scanning. In maxillary palatine, selection of distances at 12 mm, 14 mm, 16 mm, and 18 mm from the palatal apex of maxillary first molar between the maxillary first and second molar were used as measurement, measured the proximal and distal palatal widths of maxillary first and second molar and the palatal mucosal thickness and bone tissue thickness when microscrew implant anchorage nails were implanted at 30 °, 45 °, 60 °, and 90 °. SPSS 26.0 software was used for one-way ANOVA and LSD pair comparison. @*Results@#The larger the angle of the microscrew implant anchorage nail was, the smaller the proximal and distal medial widths between the maxillary first and second molar, and the difference was statistically significant (P < 0.05). Compared with the 90° direction, the proximal and distal medial widths of the microscrew implant anchorage nail were larger in the 60° direction. The greater the angle of implantation, the smaller the mucosal thickness and the greater the bone tissue thickness, and the results showed a significant difference (P < 0.001). Compared with the direction of 30° and 45°, the mucosal thickness at the direction of 60° was smaller, and the bone tissue thickness was larger. The higher the position of the microscrew implant anchorage nail, the greater the width of the proximal and distal medial, and the difference was statistically significant (P < 0.05). Compared with the positions 12 and 14 mm from the palatal tip, the proximal and distal medial widths of the microscrew implant anchorage nail were larger. The higher the implant position was, the greater the mucosal thickness and the smaller the bone tissue thickness. The results showed a significant difference (P < 0.001). Compared with the position of 18 mm from the palatal tip of the maxillary first molar, the mucosal thickness was smaller and the bone tissue thickness was larger.@*Conclusion@#It is most appropriate to implant microscrew implant anchorage nail at least 10 mm in length in the direction of 60° at the palatal apex 16 mm from the maxillary first molar in palatine between the first and second molar.

In Vitro Biodegradation Pattern of Collagen Matrices for Soft Tissue Augmentation.

Collagen matrices have become a great alternative to the use of connective tissue grafts for soft tissue augmentation procedures. One of the main problems with these matrices is their volume instability and rapid degradation. This study has been designed with the objective of examining the degradation of three matrices over time. For this purpose, pieces of 10 × 10 mm2 of Fibro-Gide, Mucograft and Mucoderm were submitted to three different degradation tests-(1) hydrolytic degradation in phosphate buffer solution (PBS); (2) enzyme resistance, using a 0.25% porcine trypsin solution; and (3) bacterial collagenase resistance (Clostridium histolyticum)-over different immersion periods of up to 50 days. Weight measurements were performed with an analytic microbalance. Thickness was measured with a digital caliper. A stereomicroscope was used to obtain the matrices' images. ANOVA and Student-Newman-Keuls tests were used for mean comparisons (p < 0.05), except when analyzing differences between time-points within the same matrix and solution, where pair-wise comparisons were applied (p < 0.001). Fibro-Gide attained the highest resistance to all degradation challenges. The bacterial collagenase solution was shown to constitute the most aggressive test as all matrices presented 100% degradation before 14 days of storage.

Collagen Matrix vs. Autogenous Connective Tissue Graft for Soft Tissue Augmentation: A Systematic Review and Meta-Analysis.

Soft tissues have been shown to be critical for the maintenance of both teeth and implants. Currently, regenerative soft tissue techniques propose the use of collagen matrices, which can avoid the drawbacks derived from the obtainment of autogenous tissue graft. A systematic review and meta-analysis were conducted to ascertain the efficacy of collagen matrices (CM) compared to autogenous connective tissue graft (CTG) to improve soft tissue dimensions. An electronic and manual literature searches were performed to identify randomized clinical trials (RCT) or controlled clinical trials (CCT) that compared CTG and CM. Pooled data of width of keratinized tissue (KT) and mucosal thickness (MT) were collected and weighted means were calculated. Heterogeneity was determined using Higgins (I2). If I2 > 50% a random-effects model was applied. Nineteen studies were included based on the eligibility criteria. When using CTG a higher MT gain (0.32 mm, ranging from 0.49 to 0.16 mm) was obtained than when employing CM. Similar result was obtained for the width of KT gain, that was 0.46 mm higher (ranging from 0.89 to 0.02 mm) when employing CTG. However, it can be stated that, although autogenous CTG achieves higher values, CM are an effective alternative in terms of total width of KT and MT gain.

Bone-level changes around implants with 1- or 3-mm-high abutments and their relation to crestal mucosal thickness: A 1-year randomized clinical trial.

AIM: To evaluate 1-year bone-level changes around subcrestal platform-switching implants with 1 or 3 mm definitive abutments. The influence of mucosal thickness on bone-level alterations was further analysed. MATERIALS AND METHODS: Implants were placed in the posterior sextants and positioned 1.5 mm subcrestally with an abutment of 1 or 3 mm height. Final restorations were delivered after 16 weeks. Radiographic measurements of inter-proximal bone level were the primary outcome and were adjusted by vertical mucosal thickness. Peri-implant clinical conditions and resonance frequency analysis were also compared. RESULTS: A total of 65 subjects with 99 implants were analysed. The overall 1-year implant survival rate between the 1- and 3-mm groups was 96.4% and 94.4%, respectively. Statistically significant lower inter-proximal marginal bone-level changes were observed in the 3-mm group (1 mm: -0.17 ± 0.02 mm at mesial and -0.21 ± 0.02 mm distal; 3 mm: -0.03 ± 0.02 mm at mesial and -0.03 ± 0.02 mm and distal; mesial: p = .001; distal: p < .001). Initial vertical mucosal thickness was not correlated with inter-proximal marginal bone loss. CONCLUSIONS: Subcrestal implants with 3-mm abutment were associated with minimal inter-proximal bone loss. Independent of the abutment height, crestal mucosal thickness was not correlated with bone loss.

Variations in vertical mucosal thickness at edentulous ridge according to site and gender measured by cone-beam computed tomography.

BACKGROUND: The vertical thickness of the peri-implant mucosa is associated with the amount of post treatment marginal bone loss. However, the variations in mucosal thickness at the different edentulous sites have been sparsely documented. The purpose of the study was to conduct a survey of the frequency distribution of variations in mucosal thickness at the different sites of the edentulous alveolar ridge and to compare them according to gender. Our study included 125 partially edentulous patients having a total of 296 implant sites. Cone-beam computed tomography (CBCT) scans were obtained by placing a diagnostic template with a radiopaque crown indicator on the ridge to determine the mucosal thickness at the crest of the alveolar ridge. RESULTS: The mucosal thickness was 3.0±1.3 mm in the maxilla, which was significantly greater than the mucosal thickness of 2.0±1.0 mm in the mandible (p<0.001). In both the maxilla and the mandible, the mucosa was the thickest in the anterior region, followed by the premolar and molar regions. Sites were further classified into two groups based on whether the mucosal thickness was greater than 2 mm. In the mandible, more than half of the sites showed a mucosal thickness of 2 mm or less. CONCLUSIONS: Although this study was a limited preoperative study, the vertical mucosal thickness at the edentulous ridge differed between the maxillary and mandibular regions. The majority of sites in the mandibular molar region had a mucosal thickness of less than 2 mm. Practitioners might be able to develop an optimal dental implant treatment plan for long-term biologic and esthetic stability by considering these factors.

Factors influencing the sinus membrane thickness in edentulous regions: a cone-beam computed tomography study.

BACKGROUND: During implant treatment in the maxillary molar area, maxillary sinus floor augmentation is often performed to ameliorate the reduced alveolar bone height attributable to bone remodeling and pneumatization-induced expansion of the maxillary sinus. However, this augmentation may cause complications such as misplaced implants, artery damage, and maxillary sinus mucosal perforation; infections like maxillary sinusitis; and postsurgical complications such as bone graft leakage and postoperative nasal hemorrhaging. To reduce the complications during maxillary sinus floor augmentation and postoperative infections, we performed retrospective investigations of various systemic and local factors that influence pre-operative sinus mucosal thickness (SMT) by using cone-beam computed tomography (CBCT). Subjects included patients who underwent maxillary sinus floor augmentation in an edentulous maxillary molar area with a lateral approach. Pre-operative SMT, existing bone mass, and nasal septum deviation were measured using CBCT images. Relationships between SMT and the following influencing factors were investigated: (1) age, (2) sex, (3) systemic disease, (4) smoking, (5) period after tooth extraction, (6) reason for tooth extraction, (7) residual alveolar bone height (RBH), (8) sinus septa, and (9) nasal septum deviation. Correlations were also investigated for age and RBH (p < 0.05). RESULTS: We assessed 35 patients (40 sinuses; 11 male, 24 female). The average patient age was 58.90 ± 9.0 years (males, 57.9 ± 7.7 years; females, 59.9 ± 9.4 years; age range, 41-79 years). The average SMT was 1.09 ± 1.30 mm, incidence of SMT > 2 mm was 25.0%, incidence of SMT < 0.8 mm was 50.0%, and the average RBH was 2.14 ± 1.02 mm. The factors that influenced SMT included sex (p = 0.0078), period after tooth extraction (p = 0.0075), reason for tooth extraction (p = 0.020), sinus septa (p = 0.0076), and nasal septum deviation (p = 0.038). CONCLUSIONS: Factors associated with higher SMT included male sex, interval following tooth extraction < 6 months, periapical lesions, sinus septa, and nasal septum deviation. Factors associated with SMT > 2 mm were sex and reason for tooth extraction, while factors associated with SMT < 0.8 mm were time following tooth extraction and nasal septum deviation. Despite the limitations of this study, these preoperative evaluations may be of utmost importance for safely conducting maxillary sinus floor augmentation.

Influence of abutment height and vertical mucosal thickness on early marginal bone loss around implants: A randomised clinical trial with an 18-month post-loading clinical and radiographic evaluation.

PURPOSE: To investigate the influence of vertical mucosal thickness on marginal bone loss around implants with short and long prosthetic abutments and the marginal bone loss progression rate up to 18 months after prosthetic loading. MATERIALS AND METHODS: Internal hex platform-switched implants were placed equicrestally using a two-stage protocol in the posterior mandible of two groups of patients with different vertical mucosal thickness, thin (≤ 2.0 mm) and thick (> 2.0 mm). Elevated prosthetic abutments of different heights (1 mm or 3 mm) were randomly assigned for single screw-retained crowns in both groups. Mesial and distal marginal bone loss were measured at implant placement (T0) and crown delivery (after 4 months [T1]), and after 6 (T2), 12 (T3) and 18 months (T4) of functional loading. RESULTS: Eighty implants were placed in eighty patients. Three patients dropped out at T2. At T4, 74 out of 77 implants were functioning, resulting in a 96% survival rate. Marginal bone loss (mean ± SE) at T2 was significantly greater in the 1-mm abutment groups (0.61 ± 0.09 mm with thin mucosa; 0.64 ± 0.07 mm with thick mucosa) than in the 3-mm abutment groups (0.32 ± 0.07 mm with thin mucosa; 0.26 ± 0.04 mm with thick mucosa). The marginal bone loss pattern over 18 months of loading showed that the greatest amount of marginal bone loss occurred during the first 6 months of function. CONCLUSIONS: Internal hex platform-switched implants placed equicrestally and restored with 1-mm abutments presented greater marginal bone loss than identical implants with 3-mm abutments, with vertical mucosal thickness having no significant influence.

Cone-beam Computed Tomographic Analysis to Detect the Association between Primary and Secondary Endodontic Infections and Mucosal Thickness of Maxillary Sinus.

INTRODUCTION: This retrospective study used cone-beam computed tomographic (CBCT) imaging to evaluate the differences in the mucosal thickness of the Schneiderian membrane in primary and secondary endodontic lesions. METHODS: A total of 121 CBCT scans were analyzed. Clinical features such as sex, age, size and volume of the periapical lesion, dimension of the bone, morphology, and relationship between the roots and the mucosal thickness were recorded and analyzed in primary and secondary endodontic lesions in CBCT sagittal and coronal planes. Data were analyzed using the chi-square test, the Mann-Whitney U test, and multiple logistic regression (P < .05). RESULTS: Statistical analysis revealed no significant differences in membrane thickness between the primary and secondary lesions in the sagittal and coronal planes (P = .08 and .06). Differences between age groups were statistically significant in both groups (P < .05). The volume of the periapical lesions of the secondary endodontic lesions were statistically greater than that of the primary lesions (P < .05). Mucosal thickness prevalence increased when the volume of the lesion was greater, and the bone dimension was narrower in maxillary second premolars and first and second molars. Teeth with 2 or more affected roots were directly related to increased sinus mucosa thickening. CONCLUSIONS: CBCT images showed no differences in mucosal thickening between primary and secondary endodontic lesions.

Factors Influencing Early Marginal Bone Loss around Dental Implants Positioned Subcrestally: A Multicenter Prospective Clinical Study.

Early marginal bone loss (MBL) is a non-infective remodeling process of variable entity occurring within the first year after implant placement. It has a multifactorial etiology, being influenced by both surgical and prosthetic factors. Their impact remains a matter of debate, and controversial information is available, particularly regarding implants placed subcrestally. The present multicenter prospective clinical study aimed to correlate marginal bone loss around platform-switched implants with conical connection inserted subcrestally to general and local factors. Fifty-five patients were enrolled according to strict inclusion/exclusion criteria by four clinical centers. Single or multiple implants (AnyRidge, MegaGen, South Korea) were inserted in the posterior mandible with a one-stage protocol. Impressions were taken after two months of healing (T1), screwed metal-ceramic restorations were delivered three months after implant insertion (T2), and patients were recalled after six months (T3) and twelve months (T4) of prosthetic loading. Periapical radiographs were acquired at each time point. Bone levels were measured at each time point on both mesial and distal aspects of implants. Linear mixed models were fitted to the data to identify predictors associated with MBL. Fifty patients (25 male, 25 female; mean age 58.0 ± 12.8) with a total of 83 implants were included in the final analysis. The mean subcrestal position of the implant shoulder at baseline was 1.24 ± 0.57 mm, while at T4, it was 0.46 ± 0.59 mm under the bone level. Early marginal bone remodeling was significantly influenced by implant insertion depth and factors related to biological width establishment (vertical mucosal thickness, healing, and prosthetic abutment height). Deep implant insertion, thin peri-implant mucosa, and short abutments were associated with greater marginal bone loss up to six months after prosthetic loading. Peri-implant bone levels tended to stabilize after this time, and no further marginal bone resorption was recorded at twelve months after implant loading.

Subcrestal Implant Placement and Recontouring Soft Tissue Using the Erbium YAG Laser to Manage Restorative Space in Implant Overdentures.

Subcrestal implant placement helps gain vertical restorative space at the location of the implants; however, this leads to the development of a tall mucosal cuff, necessitating the use of tall abutments. This article describes the technique of gaining restorative space by decreasing the height of the mucosal cuff with an Erbium YAG laser.