Effect of Advanced Platelet-Rich Fibrin (A-PRF) on Postoperative Level of Pain and Swelling Following Third Molar Surgery.

BACKGROUND: Postoperative pain and swelling following third molar (M3) removal can be debilitating, and there is interest in using advanced platelet-rich fibrin (A-PRF) to reduce their severity. PURPOSE: This study compared postoperative pain and swelling between A-PRF and gelatin dressing in extraction sockets following mandibular M3 removal. METHODS, SETTING, SAMPLE: This split-mouth, single-blinded, randomized controlled trial was completed at the Oral Surgery clinic of University of Otago between November 2020 and July 2021. Patients aged between 16 and 40 years with bilaterally impacted mandibular M3 of similar Pederson index difficulty and deemed to be American Society of Anesthesiologists (ASA) I or II comprised the study sample. PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE: The exposure variable was M3 socket management. One socket received A-PRF and 1 gelatin dressing, while the other received 2 gelatin dressings. MAIN OUTCOME VARIABLE(S): The outcome variables were postoperative pain and swelling over 7 days. Pain was measured using the visual analog scale (VAS), and swelling using stereophotogrammetry. COVARIATES: Demographic characteristics (gender, ethnicity, and age), dental anxiety, smoking status, Pederson index, and intraoperative surgical time were the covariates. ANALYSES: The two sides were compared using cross-tabulations and the McNemar test for categorical and paired t-tests for continuous variables. Statistical analysis used IBM SPSS Statistics for Windows (version 28).The Alpha level was 0.05. RESULTS: 76 (87.3%) of 87 patients who met the eligibility criteria participated in the study, and 70 patients (65.7% female; age range 16-30 years) were included in the analysis. Mean visual analog scale scores showed no statistically significant difference between the A-PRF and control sides, being 29.6 (95% CI 23.9, 35.3) and 29.5 (95% CI 23.5, 35.5) on day 2, and falling to 12.6 (95% CI 8.7, 16.5) and 14.2 (95% CI 10.0, 18.4) by day 7. Likewise, mean peak facial swelling on day 2 was recorded as 6.3 cm3 (95% CI 4.9, 7.7) and 6.6 cm3 (95% CI 5.5, 7.7), and by day 7 they were 1.1 cm3 (95% CI 0.5, 1.7) and 1.0 cm3 (95% CI 0.3, 0.7) on the A-PRF and control sides, respectively. CONCLUSIONS: A-PRF placement in M3 sockets did not reduce postoperative pain and swelling over gelatin dressing alone.

A validated predictive model for risk of nodal metastasis in node negative oral squamous cell carcinoma of the buccal mucosa and tongue.

BACKGROUND: Lymph node metastasis in oral squamous cell carcinoma (OSCC) is influenced by clinical and histopathological variables. The aim of this study was to develop a simple model to predict nodal metastasis of OSCC in clinically negative necks (cN0). METHODS: Data from patients who underwent surgery for treatment of OSCC of the tongue or buccal mucosa with neck dissection were used for model development and validation. RESULTS: Nodal metastasis was significantly associated with gender, age, tumor size, site, pattern of invasion and depth of invasion on univariate analysis. All the five variables except age were retained at the variable selection step of the model development and were used in the final model because it was not significant at 0.10 significance level after adjusting for other variables. Regression coefficients of the model were used to estimate risks of nodal metastases for each combination of clinicopathological characteristics. A 10-fold cross-validation was used to assess the model. The average of the resultant 10 AUCs (along with its 95% confidence interval estimated using bootstrap) was used as the overall validated measure of the model. A risk chart was produced using probability of nodal metastasis predicted by the model for each combination of five characteristics. The model's ability to identify patients with nodal metastases as assessed by the area under the ROC curve (AUC) was 0.752. CONCLUSION: The model based on established clinicopathological variables has been internally validated on a large cohort of patients and offers practicability for use in OSCCs of the tongue and buccal mucosa.

Third Molar Surgery Outcomes: A Randomized Clinical Trial Comparing Submucosal and Intravenous Dexamethasone.

OBJECTIVE: Swelling, pain, and trismus after third molar surgery have a negative impact on patients' quality-of-life in the days following surgery. The study aims to compare the efficacy of submucosal (SM) dexamethasone and intravenous (IV) dexamethasone in reducing these outcomes. METHODS: The single-center study was designed as a randomized, controlled, double-blinded trial with a total of 130 participants evenly allocated into 2 treatment groups. All participants underwent the surgical removal of at least 2 mandibular third molars under intravenous sedation. The outcome variables studied were swelling, pain, and maximum incisal distances. The swelling was measured using a 3-dimensional camera (3dMD Inc, Atlanta, GA). The pain was quantified using a 100 mm visual analog scale (VAS). Maximum incisal distances were measured using a caliper. Participants completed the short-form Oral Health Impact Profile (OHIP-14). The 2 groups were compared using cross-tabulations and chi-square tests for categorical variables and analysis of variance for continuous variables. RESULTS: The participants had a mean age of 22.6 years, 56.8% females and 12.4% smokers. There were no statistically significant differences in the distribution of study variables between the 2 groups. On day 2, mean facial swelling measurements were 7.3 cm3 in the IV group and 7.8 cm3 in the SM group (P > .05). The mean pain score was 31 in the IV group and 33 in the SM group (P > .05). The mean maximum incisal distances were 33.7 mm in the IV group and 34.5 mm in the SM group (P > .05). Both groups experienced poorer quality-of-life relative to baseline scores and were affected to a similar extent. CONCLUSIONS: There are no differences in swelling, pain, and trismus between submucosal and intravenous dexamethasone in third molar surgery. Submucosal dexamethasone is a straightforward and accessible route of steroid administration in patients having third molar surgery under local anesthesia only.

Oral epithelial dysplasia: Causes, quantification, prognosis, and management challenges.

Oral epithelial dysplasia is a spectrum of architectural and cytological epithelial changes caused by accumulation of genetic changes, and is associated with an increased risk of progression to squamous cell carcinoma. It is a microscopic diagnosis of immense clinical importance. The initial reports of oral potentially malignant disorders with oral epithelial dysplasia transforming to oral cancer helped in understanding the nature of oral malignancies. Since then, clinical studies on oral potentially malignant disorders have combined microscopic findings of oral epithelial dysplasia to assess the malignant transformation potential of different grades of epithelial dysplasia. A significant amount of scientific literature has amassed on oral epithelial dysplasia relating to aspects of its diagnosis and management. However, the evidence base is weak as a result of the significant variability of published research. Poorly described study methods, variability in different oral epithelial dysplasia grading systems, inter- and intra-examiner variability causing issues of reliability, inadequate sample size, and inconsistent durations of follow-up are some of the methodological issues contributing to the failure to provide dependable information. Randomized clinical trials on the malignant transformation potential of oral epithelial dysplasia and its treatment outcomes are limited. This comprehensive literature review on oral epithelial dysplasia summarizes the scientific knowledge published in the scientific literature in English since its first description. The historical development, etiological factors, grading systems, diagnostic criteria, assessment of risk factors and prevention of malignant transformation, management principles of different grades of oral epithelial dysplasia (surgical and nonsurgical), recommendations on follow-up, and prognostic indicators are discussed in detail.

Multicentre prospective evaluation of implant-assisted mandibular removable partial dentures: surgical and prosthodontic outcomes.

OBJECTIVE: To determine implant survival and prosthodontic maintenance of implant-assisted mandibular removable partial dentures in a multicentre prospective study up to 10 years. MATERIALS AND METHODS: Forty-eight participants with mandibular distal extension partial dentures were selected. A control group of 12 New Zealand participants had new conventional mandibular partial dentures made. Three test groups of 36 participants in New Zealand (n = 12), the Netherlands (n = 12) and Colombia (n = 12) had bilateral distal implants placed. Surgical and prosthodontic outcomes were documented with only healing caps placed (Stage 1) and with an attachment system (Stage 2). RESULTS: No implants failed after 3 years. Four late implant failures in three participants occurred in New Zealand (two unilateral implant failures after 5 and 8 years and two bilateral implant failures in the same participant after 6 and 10 years); two unilateral late implant failures occurred in the Netherlands and no late failures in Colombia. Implant survival rate was 92% by 10 years. Resonance frequency measurements were taken at surgery implant stability quotient (ISQ) 62.44 ± 7.46; range 40 - 79), baseline (ISQ 63.22 ± 6.17; range 50 - 74) and after 3 years (ISQ 66.38 ± 6.77; range 55 - 83). In New Zealand and Colombia, measured crestal bone levels were 2.03 ± 0.71 mm and 2.20 ± 0.81 mm, respectively, at baseline and 3 years. For Stage I, principal prosthodontic maintenance issues were loose healing caps among 10 New Zealand participants, four Colombian participants and one Netherlands participant. For Stage 2, matrix activation and overdenture puncture fractures resulted in 41 events (25 participants) in New Zealand over 10 years, whilst over 3 years, there were 14 events in nine Colombian participants and six events in five Netherlands participants. CONCLUSION: This clinical multicentre research complements previous case reports, case series, retrospective and prospective studies on the notion of implant-assisted removable partial dentures for partially edentulous patients. Late implant failures and increased prosthodontic maintenance when an attachment system is used identify the need for further research, including more robust statistical analyses.

Could the median-palate accommodate wide-bodied implants in order to support maxillary over-dentures? A radiomorphometric study of human cadavers.

INTRODUCTION: Atrophy of the alveolar bone is an irreversible multifactorial phenomenon, the rate of which varies between individuals and between the jaws. This atrophy of the alveolar ridges presents severe limitations for the oral rehabilitation of the edentulous patients and poses a clinical challenge to the prosthodontists and implant surgeons. The present research aimed to investigate whether the median-palate of elderly edentulous subjects is anatomically suitable for implant placement. MATERIALS AND METHODS: A total of 32 samples were harvested from the maxillae of 16 human cadavers. One dentate male subject was included for contrast. Bone quality and quantity were analysed at two regions: the median-palate and the edentulous maxillary alveolar ridge. Samples were scanned through micro-CT, and the region of analysis (ROA) identified and dissected. Bone volume to tissue volume ratio (%BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp) and trabecular bone pattern factor (Tb.Pf) were evaluated for the two regions using Skyscan CTAn(®). RESULTS: The results of bone volume fraction obtained from CTAn(®) of the median-palatal region show higher values than the respective premolar sites in 12 of 15 (80%) edentulous samples. However, this difference was statistically non-significant (P = 0.06). Similarly, the trabecular number for 10 of 15 samples (66.6%) from the median-palate shows greater values than the respective premolar site (P = 0.07). Trabecular thickness of 10 of 15 (66.6%) premolar samples is larger than in the median-palatal region. However, these differences were also statistically non-significant (P = 0.25). Statistically significant difference (P = 0.04) was found between the Tb.Sp values of the two regions. CONCLUSION: The results indicate that the anterior median-palate is structurally better than their respective maxillary premolar region in elderly edentulous persons, and an implant can be placed to anchor an overdenture. The best site for a wide-body implant was established to be 6-8 mm posterior to the incisive foramen in elderly edentulous patients.

The prognostic accuracy of resonance frequency analysis in predicting failure risk of immediately restored implants.

OBJECTIVES: It is of imperative clinical significance to define a safe threshold for planned immediate implant restoration. The aim of this report was to evaluate the prognostic accuracy of resonance frequency analysis (RFA) measurements recorded at two different times (implant placement and 8-week post-implant placement) and to determine the optimal threshold value for predicting failure risk of immediately restored/loaded implants. MATERIAL AND METHODS: Twenty-eight 8- or 9-mm-diameter implants were placed in either a fresh molar extraction socket or a healed site. An electronic RFA device was used to record the implant stability quotients (ISQs) at implant placement surgery, 8 weeks and 1 year. Receiver operating characteristic (ROC) analysis was used to identify the optimal cut-off level. Sensitivity and specificity were also determined at the selected cut-off value. RESULTS: The area under the ROC curve for RFA at 8 weeks was 0.93 with a significant P-value (P = 0.001). The optimum cut-off value for detecting implant stability was 60.5 ISQ measured at 8 weeks, with sensitivity and specificity of 95.2% and 71.4%, respectively. CONCLUSIONS: The implant stability measurements after 8 weeks showed a better accuracy in predicting implants that were at risk of failure than those taken at the time of implant placement.

Fractured zirconia implants and related implant designs: scanning electron microscopy analysis.

OBJECTIVES: Two fractured one-piece experimental (commercially unavailable) zirconia implants were analyzed using scanning electron microscope (SEM) analysis to identify failure origins and aid in understanding the failure mechanisms. Modifications to the zirconia implant design are suggested to minimize such fracture incidences. MATERIALS AND METHODS: Two zirconia implants fractured during the final torquing in the maxillary ridge using the prescribed hand torque wrench. The implants were subsequently retrieved and prepared for optical and SEM evaluation. Critical attention was given to the fractography (crack morphology) of the fractured implants to identify the fracture origin. RESULTS: Events related to initiation and propagation of the crack front could be detected from the morphology of the fractured surfaces. Unfavorable torque and bending forces applied on the implant during surgical placement and the inherent flaws in the material may have resulted in crack initiation and implant failure. CONCLUSIONS: Caution must be exercised when placing zirconia implants in dense bone sites. Modification of surgical protocols for the intended implant site may be necessary. Improvement in design features specific to zirconia implants, and strict quality control during manufacture is essential to minimize the likelihood of fracture.

Immediate single implant restorations in mandibular molar extraction sockets: a controlled clinical trial.

BACKGROUND: In the replacement of missing teeth, a paradigm shift is currently observed with immediate implant placement and/or restoration, particularly in the aesthetic zone. In molar sites, however, anatomical, occlusal and biomechanical considerations remain deterrent factors influencing the outcome of this treatment paradigm. The aim of this report was to evaluate immediate placement and immediate restoration of strongly tapered wide-diameter implant in fresh mandibular molar extraction sockets. METHODS: Twenty-four 8- or 9-mm diameter implants were placed in either a fresh molar extraction socket or a healed site. All the implants received provisional crowns within 48 h. The provisional crowns were replaced with full ceramic crowns after 8 weeks of implant placement. RESULTS: The overall implant success rate after 1 year of service for the 24 implants in two treatment groups was 75%. Success rates were 83.3% and 66.7% for the delayed and immediate placement groups respectively, with no significant difference observed between the two groups (P = 0.35). Implant stability measurements identified the immediately placed implants to be more stable immediately after surgery than delayed placed implants. In contrast, the delayed placed implants were more stable after 8 week healing time. CONCLUSIONS: The rehabilitation of single missing mandibular molars by immediately placed and restored wide-diameter implants was associated with a relatively high failure rate.

Trabecular bone microarchitecture in the median palate and maxillary premolar alveolar sites of edentulous elderly cadavers.

PURPOSE: The median palate has been proposed as an alternative site for implant placement supporting maxillary overdentures. The aim of our research was to compare the histologic bone microarchitecture of the median palatal and the maxillary premolar alveolar ridge in edentulous elderly human cadavers. MATERIALS AND METHODS: The bone quality and quantity were analyzed at two regions of analysis (ROA) in 16 maxilla of human cadavers: the median palate (ROA I) and edentulous maxillary alveolar premolar ridge (ROA II). Histomorphometry of the scanned images was performed using image analysis software (National Institutes of Health ImageJ). The bone volume/tissue volume ratio, trabecular thickness, trabecular separation, and trabecular number were evaluated for the two regions. RESULTS: The bone volume fraction of the median-palatal region (ROA I) was greater than at the respective premolar sites (ROA II) in 10 of 15 samples (66.6%), with mean values ranging from 19.3-61.3%. However, the results were not statistically significant (P = .151). Similarly, the trabecular number of ROA II showed greater values than that for ROA II (mean TbN for ROA I, 1.03 mm(-1) and for ROA II, 0.96 mm(-1)). However, these differences were not statistically significant (P = .454). CONCLUSIONS: These results have indicated that the anterior median palate is structurally similar to the corresponding maxillary premolar region in elderly edentulous persons. Therefore, it can be used as an implant site to anchor a maxillary overdenture in patients with atrophic maxillary ridges.

Facial attractiveness of skeletal Class II patients before and after mandibular advancement surgery as perceived by people with different backgrounds.

The purpose of this study was to determine the perceived level of improvement in facial attractiveness as assessed by people with different backgrounds in skeletal Class II patients treated by mandibular advancement with bilateral sagittal split osteotomy (BSSO). The frontal and lateral pre- and post-operative photographs of 10 Caucasian patients were selected. Changes in frontal and profile attractiveness were assessed by 10 orthodontists, 10 art students, and 10 laypersons. Frontal and lateral pre- and post-operative photographs were randomly distributed throughout two surveys. For each photograph, the evaluators ranked the attractiveness of face, chin, and lips on visual analogue scales. A third survey was administered to orthodontists only, by presenting the same pre and post-operative photographs but paired side-by-side with pre- and post-operative status disclosed. Overall, attractiveness scores after BSSO showed an 11.5 per cent improvement (95 per cent confidence intervals: 9.4-13.5 per cent) on the lateral post-operative photographs and a 7.5 per cent improvement (95 per cent confidence intervals: 5.4-9.5 per cent) on the frontal post-operative photographs. Attractiveness scores differed significantly between the groups (P = 0.015), with orthodontists being more generous with their improvement ratings and the art students tending to give a more critical assessment. There were no significant differences between male and female evaluators (P > 0.05). Ratings of before-after attractiveness almost doubled when the pre- and post-operative status was disclosed as compared to blinded evaluations, thus indicating that prior knowledge of pre- and post-treatment status markedly influences aesthetic evaluations, with a bias towards a more favourable outcome.

Titanium allergy: could it affect dental implant integration?

PURPOSE: Degradation products of metallic biomaterials including titanium may result in metal hypersensitivity reaction. Hypersensitivity to biomaterials is often described in terms of vague pain, skin rashes, fatigue and malaise and in some cases implant loss. Recently, titanium hypersensitivity has been suggested as one of the factors responsible for implant failure. Although titanium hypersensitivity is a growing concern, epidemiological data on incidence of titanium-related allergic reactions are still lacking. MATERIALS AND METHODS: A computer search of electronic databases primarily MEDLINE and PUBMED was performed with the following key words: 'titanium hypersensitivity', 'titanium allergy', 'titanium release' without any language restriction. Manual searches of the bibliographies of all the retrieved articles were also performed. In addition, a complementary hand search was also conducted to identify recent articles and case reports. RESULTS: Most of the literature comprised case reports and prospective in vivo/in vitro trials. One hundred and twenty-seven publications were selected for full text reading. The bulk of the literature originated from the orthopaedic discipline, reporting wear debris following knee/hip arthroplasties. The rest comprised osteosynthesis (plates/screws), oral implant/dental materials, dermatology/cardiac-pacemaker, pathology/cancer, biomaterials and general reports. CONCLUSION: This review of the literature indicates that titanium can induce hypersensitivity in susceptible patients and could play a critical role in implant failure. Furthermore, this review supports the need for long-term clinical and radiographic follow-up of all implant patients who are sensitive to metals. At present, we know little about titanium hypersensitivity, but it cannot be excluded as a reason for implant failure.

Mandibular single-implant overdentures: preliminary results of a randomised-control trial on early loading with different implant diameters and attachment systems.

OBJECTIVES: To determine surgical and prosthodontic outcomes of mandibular single-implant overdentures, opposing complete maxillary dentures, using a wide diameter implant and large ball attachment system compared with different regular diameter implants with standard attachment systems. MATERIALS AND METHODS: Thirty-six edentulous participants (mean age 68 years, SD 9.2) were randomly assigned into three treatment groups (n=12). A single implant was placed in the mandibular midline of participants to support an overdenture using a 6-week loading protocol. The control group received Southern regular implants and standard ball attachments. One group received Southern 8-mm-wide implants and large ball attachments. Another group received Neoss regular implants and Locator attachments. Parametric and non-parametric tests of a statistical software package (SPSS) were used to determine between groups differences in marginal bone loss, implant stability, implant, and prosthodontic success (P<0.05). RESULTS: Implant success after 1 year was 75% for Southern regular implant (control) group; and 100% for the Southern wide and Neoss regular implant groups (P=0.038). Mean marginal bone loss at 1 year was 0.19 mm (SD 0.39) without significant differences observed. Implant stability quotient (ISQ) at baseline was significantly lower for the Southern regular (control) group than the other two groups (P=0.001; P=0.009). At 1 year, no significant difference in implant stability was observed (mean ISQ 74.6, SD 6.1). The change in implant stability from baseline to 1 year was significant for the control group (P=0.025). Prosthodontic success was comparable between the groups but the maintenance (41 events overall, mean 1.2) was greater for the Locator and the standard ball attachments. CONCLUSIONS: Mandibular single-implant overdentures are a successful treatment option for older edentulous adults with early loading protocol using implants of different diameters and with different attachment systems.

A case series of odontogenic keratocysts from a New Zealand population over a 20-year period.

PURPOSE: To report on the clinicopathological aspects of odontogenic keratocysts (OKC)/keratocystic odontogenic tumours (KCOT) presenting in a New Zealand population. METHODS: Information on defined areas--including age at presentation, gender, anatomical sub-location, presenting features, histological subtype and the recurrence pattern--were extracted from the histopathological data available in the Oral Pathology database of the University of Otago School of Dentistry. RESULTS: Two hundred and twenty three cases of OKC/ KCOT were identified over the period ranging from 1987 to 2008. Mean age at presentation was 37.0 years (males 38.6 years, females 34.4 years), with 61.0% of cases being male. The mandible was the dominant jaw affected, with 65.9% of lesions, with the angle of mandible being the commonest anatomical sub-location (with 32.4% of lesions). One-fifth of the cases were asymptomatic incidental findings, while the majority of problems were related to the third molar tooth and/or pain and swelling. The overall recurrence rate was 18.3%, with the majority (62.2%) in the mandible and more males (67.5%) affected. Recurrence was highest in the first 5 years of follow-up, and decreased sharply thereafter. CONCLUSION: This study is the first to describe the frequency, distribution, presentation and recurrence rates of OKC/KCOT in New Zealand and shows that these are similar to those reported from other populations.

A nine-year review of orthognathic surgery at the University of Otago.

OBJECTIVE: To describe the demographic characteristics of patients undergoing orthognathic surgery at the University of Otago over a nine-year period. METHODS: The case notes of patients who underwent orthognathic surgery procedures at the University of Otago from 2001 to 2009 were reviewed retrospectively. This was augmented with a brief literature review of surgical considerations and complications in orthognathic surgery among older patients. RESULTS: The 92 patients included in the study were aged 15 to 56 years. The mean patient age increased over the nine-year observation period, from 22.1 years (sd, 9.4) during 2001-2003, 25.0 years (sd, 12.7) during 2004-2006, to 27.7 years (sd, 11.4) during 2007-2009. Most patients were from New Zealand European or European backgrounds, with only 5.5% identifying as Maori, and 3.3% as Asian. A female preponderance was observed (with a female:male ratio of 1.6:1). Complications were encountered with 24 patients (26.1%). Ten patients had long-term (lasting for one year or more) sensory nerve disturbance; all of those had undergone a mandibular bilateral sagittal split osteotomy (BSSO) procedure (they comprised 12.7% of all BSSO patients treated); half of those patients were over 35 years old, and four were over 40 years old. CONCLUSIONS: There has been an increase in the proportion of older patients undergoing orthognathic surgery at the University of Otago. Observations from this case series support findings from other studies demonstrating a higher rate of sensory nerve disturbance among older BSSO patients.

HGF/MET in osteogenic differentiation of primary human palatal periosteum-derived mesenchymal stem cells.

PURPOSE: This study aimed to determine expressions of hepatocyte growth factor (HGF) and MET proto-oncogene receptor tyrosine kinase (MET) in palatal periosteum (PP) and to examine the effect of HGF/MET on osteogenic differentiation of human palatal periosteum-derived mesenchymal stem cells (PD-MSCs). METHODS: HGF/MET proteins in human palatal periosteum (n = 3) were localized using immunohistochemistry. PD-MSCs (n = 3) were cultured in serum-free Essential 8 (E8) medium or osteogenic medium with and without Capmatinib, a selective ATP-inhibitor of MET. HGF concentration in vitro was measured with ELISA. Relative gene expression was quantified from PD-MSCs by quantitative reverse transcription real-time polymerase chain reaction. RESULTS: Immunohistochemistry detected co-localization of HGF and MET protein in PP. HGF protein levels were significantly higher (P < 0.05) in osteogenic media (day 21: 12.19 ± 8.36 ng/mL) than in E8 medium (day 21: 0.42 ± 0.72 ng/mL). MET inhibitor had a limited feedback effect on the expression profile of the osteogenic genes tested. Gene expression levels for all but three genes were comparable in serum-free and osteogenic media at all time points. CONCLUSION: HGF/MET present in human PP and HGF is upregulated in vitro during osteogenesis; however the targeted pathways controlled by MET may not involve osteoblast maturation.

Primary stability measurements of single implants in the midline of the edentulous mandible for overdentures.

OBJECTIVES: To determine the primary stability of the Southern wide diameter (8 mm) implants, Neoss regular diameter (4 mm) implants, and Southern regular diameter (3.75 mm) implants placed in the midline of edentulous mandibles for single-implant overdentures. Variables related to host site and implant characteristics were investigated to determine their influence on the primary stability of the implants. MATERIALS AND METHODS: A total of 36 implants were placed in the midline symphysis of the edentulous mandibles of 36 participants. Their primary stability was then measured using the magnetic Osstell mentor device. Analysis of variance (ANOVA) was used to compare the mean implant stability quotient (ISQ) scores with one-way ANOVA for multiple comparisons. RESULTS: The highest measurement (ISQ) of primary stability was for the Southern 8 mm wide diameter implants (84.8, SD 9.8), followed by the Neoss 4 mm regular diameter (82.3, SD 4.8) implants and the Southern 3.75 mm regular diameter implants (75.3, SD 8.4), respectively. The Southern 3.75 mm regular diameter implants had a significantly lower mean ISQ value than the same system 8 mm wide diameter (P=0.004) and the Neoss 4 mm regular diameter implants (P=0.03). No significant differences were observed between the 8 mm and the 4 mm diameter implants (P>0.05). CONCLUSIONS: Host-site variables such as age, gender, bone volume, and quality do not appear to influence the primary stability of the implants. No clear correlation was established between ISQ values and implant diameter.

Immediate placement or immediate restoration/loading of single implants for molar tooth replacement: a systematic review and meta-analysis.

PURPOSE: This systematic review and meta-analysis assessed the survival of immediately placed single implants in fresh molar extraction sites and immediately restored/loaded single molar implants in healed molar sites. MATERIALS AND METHODS: A search of the main electronic databases, including the Cochrane Oral Health Group's Trials Register, was conducted up to November 1, 2008. The meta-analysis was prepared in accordance with the guidelines of the Academy of Osseointegration Workshop on the State of the Science on Implant Dentistry. The data were analyzed with statistical software. RESULTS: For immediately placed molar implants, nine studies describing 1,013 implants were included to support a survival rate of 99.0%. There were no significant differences between immediate and delayed loading/restoration in molar sites (relative risk of 0.30, 95% confidence interval 0.05 to 1.61; P = .16). For immediate restoration/loading of single implants in healed molar sites, seven studies with 188 single implants were identified. In this case, the implant survival rate was 97.9%, with no difference between immediate and delayed loading (relative risk of 3.0, 95% confidence interval: 0.33 to 27.16; P = .33). Favorable marginal bone level changes in the immediate loading group were detected at 12 months (mean difference of -0.31, 95% confidence interval: -0.53 to -0.096; P = .005). CONCLUSIONS: The protocols of immediate placement and immediate restoration/loading of single implants in mandibular molar regions showed encouraging results.

Mandibular single-implant overdentures: a review with surgical and prosthodontic perspectives of a novel approach.

OBJECTIVES: To review the literature on mandibular single-implant overdentures (opposing complete maxillary dentures), and present surgical and prosthodontic perspectives of a novel approach for this treatment option. MATERIAL AND METHODS: An electronic search through the databases of Pubmed, Embase and Medline using the linked key words 'mandibular single implant overdentures' was performed. The search was limited to English language articles published up to August 2008. Hand searches through articles retrieved from the electronic search, peer-reviewed journals and recent conference proceedings were also conducted. RESULTS: A limited number of reports were identified on mandibular single-implant overdentures (opposing maxillary complete dentures). They comprised of case-series reports, short-term prospective trials and current randomized-controlled clinical trials. Different loading protocols with different implant systems have been used, but always with regular diameter implants. Specific anatomical and vascular dangers of the mandibular midline symphysis are identified including a novel surgical approach using a currently available short, wide diameter tapered implant. In addition, the prosthodontic rationale for using a larger attachment system (incorporating a platform switch) for mandibular single-implant overdentures is described. CONCLUSION: The review reveals that there is a lack of published randomized clinical trials using mandibular single-implant overdentures, opposing maxillary complete dentures. Without the evidence from randomized clinical trials, routine use of this novel approach cannot be recommended, compared with using regular diameter implants and matching attachment systems.