Comparison of the accuracy of implant position among freehand implant placement, static and dynamic computer-assisted implant surgery in fully edentulous patients: a non-randomized prospective study

The optimal implant position is a critical factor for long-term success in fully edentulous patients. Implants can be placed through conventional freehand, static computer-assisted implant surgery (CAIS), or dynamic CAIS protocols, but at present there is very limited clinical evidence on their accuracy in fully edentulous patients. This study was performed to evaluate the accuracy of implant placement using three protocols in fully edentulous patients. Thirteen patients received 60 implants with the freehand (n = 20), static CAIS (n = 20), or dynamic CAIS (n = 20) protocol. Postoperative cone beam computed tomography was utilized to evaluate the accuracy of implant placement in relation to the planned optimal position. The data were analysed by ANCOVA followed by Bonferroni analysis. The mean angular deviation (standard deviation) in the freehand, static CAIS, and dynamic CAIS groups was 10.09° (4.64°), 4.98° (2.16°), and 5.75° (2.09°), respectively. The mean three-dimensional deviation (standard deviation) at the implant platform in the freehand, static CAIS, and dynamic CAIS groups was 3.48 (2.00) mm, 1.40 (0.72) mm, and 1.73 (0.43) mm, while at the implant apex it was 3.60 (2.11) mm, 1.66 (0.61) mm, and 1.86 (0.82) mm, respectively. No difference in terms of accuracy was found between static and dynamic CAIS; both demonstrated significantly higher accuracy when compared to the freehand protocol in fully edentulous patients.

Autogenous tooth bone graft material prepared chairside and its clinical applications: a systematic review

This systematic review was conducted to evaluate the available literature on the clinical outcomes of the use of autogenous tooth bone graft prepared chairside, and its current applications. A literature search was done to answer the focused questions "In partially edentulous patients, what are the alveolar ridge volumetric changes, histological findings, and implant survival rates in sites augmented with autogenous tooth bone graft prepared chairside?" Twenty articles were included at the end of the database search. Reported alveolar bone dimension changes after ridge preservation ranged between - 0.64 mm and + 2.26 mm for height, and between - 1.21 mm and + 0.41 mm for width. Augmented sites showed a significant increase in their dimensions in all investigations. The implant survival rate was 98.8% for delayed placement and 97.4% for immediate placement. Additional reports were found on the percentage bone formation following the use of this graft at different postoperative time points, which showed a higher bone volume with time. Currently available studies have included small samples, with short follow-up periods, and most have lacked a control group. Within the limitations of this review, the available evidence suggests that the autogenous tooth bone graft prepared chairside is as effective as other bone grafting materials.

Dentists' Attitudes Toward Dental Implant Maintenance in Thailand

INTRODUCTION

As implant therapy is a widely applied treatment modality, general dentists are in the frontline of maintaining health in patients with implants. It is however unknown to what extent general dentists are competent and feel prepared to deliver maintenance of implants to patients.

OBJECTIVES

The aim of this study was to investigate the attitudes and self-reported and objectively assessed competences of general dentists with maintenance of dental implants in patients.

METHODS

A questionnaire designed and validated for the purpose of the study, including attitudes and self-reported and objectively assessed competences, was distributed by means of an online platform.

RESULTS

Data from 429 questionnaires were included in the study. Half of the participants were 28 to 33 y old and 78% had been working <10 y. Seventy-eight percent believed that dental implant maintenance should be performed by general dentists, but only 51% were prepared to do this, citing obstacles such as insufficient knowledge and limitations of their working environment. The mean ± SD objectively assessed competence score was 8.97 ± 2.74 of 17. There were significant differences (P < 0.001, 1-way analysis of variance) in the scores among dentists who offered the full range of maintenance and management of complications (10.83 ± 2.45) with those willing to provide comprehensive oral examination and implant maintenance only (9.31 ± 2.73), those offering comprehensive examination but unwilling to conduct maintenance (8.22 ± 2.28), and those who refer all dental implant patients elsewhere (7.2 ± 2.66). Around half of the dentists believed that implants last for life.

CONCLUSIONS

While general dentists appeared to largely acknowledge the importance of providing implant maintenance care and present with positive attitudes, a large portion was unwilling to engage with maintenance of implants in patients and appeared to lack essential competences to this end. The main obstacles for providing implant maintenance care included insufficient knowledge and lack of a properly equipped clinical environment.

KNOWLEDGE TRANSFER STATEMENT

The results of this study can identify deficiencies in the currently available maintenance competences and schemes for patients with implants. These results can also help dental professionals, scientific bodies, and associations to design appropriate education and professional development strategies that can strengthen the confidence and competences of general dentists, thus offering better service to the public.

PRTFDC1, a possible tumor-suppressor gene, is frequently silenced in oral squamous-cell carcinomas by aberrant promoter hypermethylation

Array-based comparative genomic hybridization (array-CGH) has good potential for the high-throughput identification of genetic aberrations in cell genomes. In the course of a program to screen a panel of oral squamous-cell carcinoma (OSCC), cell lines for genomic copy-number aberrations by array-CGH using our in-house arrays, we identified a 3-Mb homozygous deletion at 10p12 in 1 of 18 cell lines (5.6%). Among seven genes located within this region, expression of PRTFDC1 mRNA was not detected in 50% (9/18) or decreased in 5.6% (1/18) of OSCC cell lines, but detected in normal oral epithelia and restored in gene-silenced OSCC cells without its homozygous loss after treatment with 5-aza-2'-deoxycytidine. Among 17 cell lines without a homozygous deletion, the hypermethylation of the PRTFDC1 CpG island, which showed promoter activity, was observed in all nine cell lines with no or reduced PRTFDC1 expression (52.9%). Methylation of this CpG island was also observed in primary OSCC tissues (8/47, 17.0%). In addition, restoration of PRTFDC1 in OSCC cells lacking its expression inhibited cell growth in colony-formation assays, whereas knockdown of PRTFDC1 expression in OSCC cells expressing the gene promoted cell growth. These results suggest that epigenetic silencing of PRTFDC1 by hypermethylation of the CpG island leads to a loss of PRTFDC1 function, which might be involved in squamous cell oral carcinogenesis.

Central neurilemmoma of the jaw in concurrence with radicular cyst: a case report

We report the features of a central neurilemmoma in the mandible of a patient having an inflammatory apical dental (radicular) cyst in the same region. A 29-year-old woman complained of numbness on the right side of the lower lip of 3 months duration and noted following endodontic therapy to the right mandibular first molar tooth. Panoramic radiography revealed a bilocular radiolucency in the right body of the mandible. Excisional biopsy was performed. The histopathology revealed neurilemmoma of the mandible in concurrence with inflammatory apical dental (radicular) cyst. No recurrence was detected during a 1-year follow-up.

Identification of target genes within an amplicon at 14q12-q13 in esophageal squamous cell carcinoma

Comparative genomic hybridization studies have revealed frequent amplification of the 14q12-q13 region in esophageal squamous cell carcinoma (ESC) cell lines. To identify genes targeted for amplification, we first defined the minimal common region of amplification using fluorescence in situ hybridization in affected ESC cell lines. The amplicon covered about 6 Mb, between markers D14S1034 and L18528. Then we screened 32 ESC cell lines to discern amplifications and expression levels of 26 expressed sequence tags (ESTs) that had been localized to the amplified region. Five known genes (BAZ1A, SRP54, NFKBIA, MBIP, and HNF3A) and two uncharacterized ESTs (GenBank Accession numbers AA991861 and AA167732) within the amplicon showed amplification and consequent overexpression. Two of these transcripts were amplified in three of the primary ESCs we examined. Our findings suggest that these seven genes are candidate targets of the amplification mechanism and therefore may be associated, together or separately, with development and progression of ESC.

Identification of cIAP1 as a candidate target gene within an amplicon at 11q22 in esophageal squamous cell carcinomas

Amplification of chromosomal DNA is thought to be one of the mechanisms that activate cancer-related genes in tumors. In a recent study, we identified high copy-number amplification at 11q21-q23 in cell lines derived from esophageal squamous cell carcinomas (ESCs) using comparative genomic hybridization. Because 11q21-q23 amplification has been reported in tumors of various other types as well, gene(s) associated with tumor progression may lie within this chromosomal region. To identify the most likely target(s) for amplification at 11q21-q23, we determined the extent of the amplicon by fluorescence in situ hybridization and then analyzed ESC cell lines for expression levels of 11 known genes and one uncharacterized transcript present within the 1.8-Mb commonly amplified region. Only cIAP1, a member of the IAP (antiapoptotic) gene family, was consistently overexpressed in cell lines that showed amplification. Additionally, the cIAP1 protein was overexpressed in the primary tumors from which those cell lines had been established. The ESC cell lines with cIAP1 amplification were resistant to apoptosis induced by chemotherapeutic reagents. An increase in cIAP1 copy number was also detected in 4 of 42 (9.5%) primary ESC tumors that were not related to the cell lines examined. Because inhibition of apoptosis seems to be an important feature of carcinogenesis, cIAP1 is likely to be a target for 11q21-23 amplification and may be involved in the progression of ESC, as well as other malignancies.

SNO is a probable target for gene amplification at 3q26 in squamous-cell carcinomas of the esophagus

Amplification of the 3q26 region appears to occur frequently among esophageal squamous cell carcinomas (ESCs). We examined ESC cell lines for amplification and expression levels of four genes in this region: SNO and EVI1, which encode proteins antagonizing transforming growth factor-beta signaling, and two other putative target genes, TERC and PIK3CA. Amplification of SNO was accompanied by significant increases in its expression level, suggesting that this gene is activated in an amplification-dependent manner. SNO was also amplified in 5 of 44 primary ESCs (11.4%). However, expression levels of EVI1, TERC, and PIK3CA did not correlate with their copy-numbers, even though EVI1 and TERC showed the same amplification pattern as SNO. Taken together, the data suggest that of the four candidates, SNO is the most probable target in the 3q26 amplicon for involvement in the progression of ESC.

A novel amplicon at 9p23 - 24 in squamous cell carcinoma of the esophagus that lies proximal to GASC1 and harbors NFIB

The non-random amplification of DNA at 9p23 - 24 observed in various types of human cancers, including esophageal squamous cell carcinomas (ESCs), may reflect the locations of important tumor-associated genes. Our previous studies using ESC cell lines defined an amplicon in this region and identified a novel gene, GASC1, as a target of the amplification. Since different regions within the same chromosome arm are often involved in amplification in a syntenic or non-syntenic manner, we characterized the amplicon at 9p23 - 24 in 35 ESC cell lines (29 KYSE series and 6 YES series), and examined possible involvement of non-syntenic amplifications at 9p23 - 24 in 32 primary ESCs. Our results clearly indicated that two target regions for DNA amplification exist at 9p23 - 24; the major amplicon contains GASC1, and the minor one harbors a transcription factor, NFIB, centromeric to the GASC1 locus.

Nonrandom chromosomal imbalances in esophageal squamous cell carcinoma cell lines: possible involvement of the ATF3 and CENPF genes in the 1q32 amplicon

Using comparative genomic hybridization (CGH), we investigated copy number aberrations in 29 esophageal squamous cell carcinoma (ESC) cell lines. All lines displayed numerous chromosome imbalances. The most frequent losses were observed on chromosome 18q (65.5%), Xp (48. 3%), 3p (44.8%), 4q (44.8%), 8p (41.4%), 11q23 - 25 (34.5%) and 4p (27.6%), whereas the most common copy number gains were noted at 8q (86.2%), 3q (82.8%), 5p (69%), 7p (69%), 20q (65.5%), 9q (55.2%), 11q (55.2%), 1q (48.3%), Xq (44.8%) and 18p (37.9%). High-level gains (HLGs) were detected at 3q26 (9 cases), 8q23 (6 cases), 5p14 - 15 (6 cases), 18p11.2 - 11.3 (6 cases), 3q27 - 28 (5 cases), 5p13 (3 cases), 7p14 - 15 (3 cases), 20q12 - 13 (3 cases), 11q13 (3 cases), 14q21 (2 cases), 20p11.2 (2 cases), 13q32 (2 case), and 1q32 (1 case). Among them, HLGs of 1q32 have been reported in other types of cancer, including glioblastoma and breast cancers. We successfully narrowed down the smallest common amplicon involving 1q-gain to the genomic segment between D1S414 and D1S2860 by fluorescence in situ hybridization (FISH). Southern and northern blot analysis clearly demonstrated that ATF3, human activating transcription factor-3 and CENPF, centromere protein F, mapped within this region, were significantly amplified and over-expressed in 1q32 amplicon.

Amplification and overexpression of TGIF2, a novel homeobox gene of the TALE superclass, in ovarian cancer cell lines

Homeodomain transcription factors play important roles in directing cellular proliferation and differentiation. A TALE-superclass homeodomain protein, multifunctional repressor of TGFbeta-induced transcription. Here we report identification of TGIF2, a novel TALE-superclass homeodomain protein that shows distinct homology with TGIF, especially in its DNA-binding domain. TGIF2 is expressed ubiquitously in human tissues, with the highest levels being found in heart, kidney, and testis. The TGIF2 product contains a putative nuclear localization signal; translocation of the protein to the nucleus was confirmed by transfection of epitope-tagged cDNA. TGIF2 lies on chromosome 20q11.2-12. Since amplification of 20q is often observed among ovarian cancers, we determined the status of DNA copy-number and expression of TGIF2 in 14 ovarian-cancer cell lines. This gene was over-expressed in all lines that showed amplification by FISH analysis. The results suggested that TGIF2 may play an important role in the development and/or progression of some ovarian tumors through a mechanism of gene amplification.

Identification of a novel gene, GASC1, within an amplicon at 9p23-24 frequently detected in esophageal cancer cell lines

In a recent study, we identified frequent amplification of DNA copy number at chromosome 9p23-24 in cell lines derived from esophageal squamous cell carcinomas (ESCs), using comparative genomic hybridization. Because amplified regions often harbor oncogenes and/or other tumor-associated genes, and because 9p23-24 amplification had been reported in various other types of cancers, we used fluorescence in situ hybridization and Southern blot analysis to map the 9p23-24 amplicon. We then screened target genes/transcripts present within this amplicon by Northern blotting. With this strategy, we successfully cloned a novel gene, designated gene amplified in squamous cell carcinoma 1 (GASC1), that was amplified and overexpressed in several ESC cell lines. The deduced amino acid sequence of GASC1 contains two PHD-finger motifs and a PX domain. PHD-finger motifs are found in nuclear proteins that participate in chromatin-mediated transcriptional regulation and are present in a number of proto-oncogenes. Our findings suggest that overexpressed GASC1 may play an important role in the development and/or progression of various types of cancer including ESC.