OCD and somatostatin


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(Updated 8/9/04)

Altemus M, Pigott T, L'Heureux F, Davis CL, Rubinow DR, Murphy DL, Gold PW.
CSF somatostatin in obsessive-compulsive disorder.
Am J Psychiatry. 1993 Mar;150(3):460-4.
"OBJECTIVE: Because the central administration of somatostatin to experimental animals produces behaviors with some similarities to the compulsions of patients with obsessive-compulsive disorder and because serotonin reuptake inhibitors have been reported to reduce brain content of somatostatin, the authors examined central somatostatin activity in patients with obsessive-compulsive disorder. METHOD: CSF for measurement of somatostatin was obtained from 15 drug-free outpatients with obsessive-compulsive disorder and 27 normal volunteers. RESULTS: The mean CSF somatostatin level was significantly higher in the patients with obsessive-compulsive disorder than in the normal subjects. CONCLUSIONS: Although the functional significance of this finding is unknown, these data are consistent with a role for somatostatin in the clinical symptomatology of obsessive-compulsive disorder and its response to neuropharmacological agents. The high levels of CSF somatostatin reported here in a patient subgroup whose predominant symptoms consisted of overly focused, perseverative thought processes are in contrast to the consistently low levels of CSF somatostatin seen in patients with a spectrum of disorders characterized by substantial cognitive deficits." [Abstract]

Schettini G.
Brain somatostatin: receptor-coupled transducing mechanisms and role in cognitive functions.
Pharmacol Res. 1991 Apr;23(3):203-15.
" Biological studies on the effects of increased brain somatostatin showed a facilitation in learning behavioural tasks, while brain somatostatin depletion by cysteamine caused memory loss. These observations, along with the severe somatostatinergic neurotransmission impairment demonstrated in Alzheimer's patients, strongly suggest a fundamental role for somatostatin in the modulation of cognitive functions." [Abstract]

Roy BF, Benkelfat C, Hill JL, Pierce PF, Dauphin MM, Kelly TM, Sunderland T, Weinberger DR, Breslin N.
Serum antibody for somatostatin-14 and prodynorphin 209-240 in patients with obsessive-compulsive disorder, schizophrenia, Alzheimer's disease, multiple sclerosis, and advanced HIV infection.
Biol Psychiatry. 1994 Mar 1;35(5):335-44.
"Patients with obsessive-compulsive disorder (OCD) demonstrated significant levels of antibody for somatostatin-28, its C-terminal fragment somatostatin-14, and prodynorphin. In contrast there were lower levels of reactivity for somatostatin-28(1-14) (the N-terminal fragment of somatostatin-28) and negligible reactivity for several other peptides including beta-endorphin and corticotropin. Healthy volunteers and disease controls [schizophrenia, Alzheimer's disease, multiple sclerosis, and subjects with advanced human immunodeficiency virus (HIV) infection] exhibited negligible reactivity. These data raise the consideration of an autoimmune mechanism for some OCD." [Abstract]

Allen JP, Hathway GJ, Clarke NJ, Jowett MI, Topps S, Kendrick KM, Humphrey PP, Wilkinson LS, Emson PC.
Somatostatin receptor 2 knockout/lacZ knockin mice show impaired motor coordination and reveal sites of somatostatin action within the striatum.
Eur J Neurosci. 2003 May;17(9):1881-95.
"The peptide somatostatin can modulate the functional output of the basal ganglia. The exact sites and mechanisms of this action, however, are poorly understood, and the physiological context in which somatostatin acts is unknown. Somatostatin acts as a neuromodulator via a family of five 7-transmembrane G protein-coupled receptors, SSTR1-5, one of which, SSTR2, is known to be functional in the striatum. We have investigated the role of SSTR2 in basal ganglia function using mice in which Sstr2 has been inactivated and replaced by the lacZ reporter gene. Analysis of Sstr2lacZ expression in the brain by beta-galactosidase histochemistry demonstrated a widespread pattern of expression. By comparison to previously published in situ hybridization and immunohistochemical data, Sstr2lacZ expression was shown to accurately recapitulate that of Sstr2 and thus provided a highly sensitive model to investigate cell-type-specific expression of Sstr2. In the striatum, Sstr2 expression was identified in medium spiny projection neurons restricted to the matrix compartment and in cholinergic interneurons. Sstr2 expression was not detected in any other nuclei of the basal ganglia except for a sparse number of nondopaminergic neurons in the substantia nigra. Microdialysis in the striatum showed Sstr2-null mice were selectively refractory to somatostatin-induced dopamine and glutamate release. In behavioural tests, Sstr2-null mice showed normal levels of locomotor activity and normal coordination in undemanding tasks. However, in beam-walking, a test of fine motor control, Sstr2-null mice were severely impaired. Together these data implicate an important neuromodulatory role for SSTR2 in the striatum." [Abstract]

Hathway GJ, Humphrey PP, Kendrick KM.
Somatostatin induces striatal dopamine release and contralateral turning behaviour in the mouse.
Neurosci Lett. 2004 Mar 25;358(2):127-31.
"Application of somatostatin to the striatum of the anaesthetized rat has previously been shown to elicit large increases in extracellular levels of dopamine and GABA via a glutamate-dependent mechanism. These actions have been ascribed to the SSTR2 receptor. Here we describe experiments designed to investigate whether these effects occur in C57Bl6 mice and if they elicit rotational behaviours associated with increased dopamine in the striatum. Application of somatostatin resulted in increased concentrations of dopamine in striatum, hippocampus and amygdala of anaesthetized mice. Unilateral striatal infusions of the peptide by retrodialysis increased locomotion. Application of N-methyl-D-aspartate and AMPA to the freely-moving mouse striatum resulted in increased dopamine release; however, only AMPA caused increased locomotion. These results further confirm that somatostatin can play a role in the control of locomotor function by modulating striatal dopamine release." [Abstract]

Magalie Rocheville, Daniela C. Lange, Ujendra Kumar, Shutish C. Patel, Ramesh C. Patel, and Yogesh C. Patel
Receptors for Dopamine and Somatostatin: Formation of Hetero-Oligomers with Enhanced Functional Activity
Science 2000; 288 (5463) : 154-157. (in Reports)
"Somatostatin and dopamine are two major neurotransmitter systems that share a number of structural and functional characteristics. Somatostatin receptors and dopamine receptors are colocalized in neuronal subgroups, and somatostatin is involved in modulating dopamine-mediated control of motor activity. However, the molecular basis for such interaction between the two systems is unclear. Here, we show that dopamine receptor D2R and somatostatin receptor SSTR5 interact physically through hetero-oligomerization to create a novel receptor with enhanced functional activity. Our results provide evidence that receptors from different G protein (heterotrimeric guanine nucleotide binding protein)-coupled receptor families interact through oligomerization. Such direct intramembrane association defines a new level of molecular crosstalk between related G protein-coupled receptor subfamilies." [Full Text]

Bendotti C, Tarizzo G, Fumagalli F, Baldessari S, Samanin R.
Increased expression of preproneuropeptide Y and preprosomatostatin mRNA in striatum after selective serotoninergic lesions in rats.
Neurosci Lett. 1993 Oct 1;160(2):197-200.
"The levels of neuropeptide Y and somatostatin may change when serotoninergic neurotransmission is altered in different brain regions. To assess whether serotonin regulates the synthesis of these peptides, we measured the levels of preproneuropeptide Y (ppNPY) and preprosomatostatin (ppSOM) mRNA in different brain regions after intracerebroventricular injection of 5,7-dihydroxytryptamine (5,7-DHT), a selective serotonin neurotoxin. The mRNA of these peptides significantly increased in the striatum but not in hippocampus and frontal cortex. It thus appears that serotonin has an inhibitory effect on the biosynthesis of neuropeptide Y and somatostatin in striatum whereas it probably acts by stimulating the release of these peptides in hippocampus and frontal cortex." [Abstract]

Mota A, Bento A, Penalva A, Pombo M, Dieguez C.
Role of the serotonin receptor subtype 5-HT1D on basal and stimulated growth hormone secretion.
J Clin Endocrinol Metab. 1995 Jun;80(6):1973-7.
"Our results indicate that 5-HT1D receptors have a stimulatory effect on GH secretion, possibly by inhibiting hypothalamic somatostatin release." [Abstract]

Mundo E, Richter MA, Zai G, Sam F, McBride J, Macciardi F, Kennedy JL.
5HT1Dbeta Receptor gene implicated in the pathogenesis of Obsessive-Compulsive Disorder: further evidence from a family-based association study.
Mol Psychiatry 2002;7(7):805-9
"Obsessive-Compulsive Disorder (OCD) is a psychiatric condition with strong evidence for a genetic component and for the involvement of genes of the serotonin system. In a recent family-based association study we reported an association between the G allele of the G861C polymorphism of the 5HT1Dbeta receptor gene and OCD. The aim of the present study was to further investigate for the presence of linkage disequilibrium between each of two polymorphisms of the 5HT1Dbeta receptor gene and OCD in a larger sample of OCD families. In a total of 121 families the G861C and the T371G polymorphisms of the 5HT1Dbeta receptor gene were genotyped using standard protocols. The genotyping data were analyzed with a new extension of the Transmission Disequilibrium Test (FBAT). The phenotypes considered in the analyses were the diagnosis of OCD and two quantitative phenotypes related to the diagnosis and clinically relevant, ie, the age at onset and the severity of OCD symptoms. We confirmed the previously found preferential transmission of the G861 allele to the affected subjects (z = 2.262, P = 0.02). No significant association was found between the polymorphism and the quantitative phenotypes considered. These results represent a confirmation of our previous published study and thus, could have important implications for the role of the 5HT1Dbeta receptor gene in the pathogenesis and treatment of OCD. Further genetic investigations on this marker considering additional polymorphisms and other quantitative phenotypes related to OCD are warranted." [Abstract]

Prosperini E, Rizzi M, Fumagalli F, Tarizzo G, Samanin R, Bendotti C.
Acute and chronic treatments with citalopram lower somatostatin levels in rat brain striatum through different mechanisms.
J Neurochem. 1997 Jul;69(1):206-13.
"The suggestion that somatostatin is involved in the pathophysiology of obsessive-compulsive disorder and the evidence that selective serotonin reuptake inhibitors show significant antiobsessional effect prompted us to examine the effect of citalopram, a selective and potent serotonin reuptake inhibitor, on the somatostatinergic system in different brain regions of the rat. A single intraperitoneal injection of 10 mg/kg citalopram significantly reduced somatostatin levels in the striatum and nucleus accumbens after 4 but not 1, 8, or 24 h. No changes were found in hippocampus. In addition, we found that the K+-evoked overflow of somatostatin-like immunoreactivity from striatal slices was significantly increased 1 h after a single injection of citalopram and was still higher, although not significantly, 4 h after the drug injection. Levels of preprosomatostatin mRNA were unchanged in striatum and accumbens 1 and 4 h after a single drug administration. In rats treated with citalopram (10 mg/kg i.p.) twice daily for 14 days, the levels of somatostatin and its mRNA were significantly decreased in the striatum but not in other brain regions 24 h after the last dose. No change was found in the basal or K+-evoked overflow of somatostatin-like immunoreactivity at 1, 4, and 24 h after the last drug injection. These results suggest that acute and chronic treatment with citalopram reduces somatostatin levels in striatum by different mechanisms. Whereas a single dose of the drug reduces somatostatin levels by increasing the release of the peptide, repeated drug treatment reduces the biosynthesis of somatostatin." [Abstract]

Altemus M, Swedo SE, Leonard HL, Richter D, Rubinow DR, Potter WZ, Rapoport JL.
Changes in cerebrospinal fluid neurochemistry during treatment of obsessive-compulsive disorder with clomipramine.
Arch Gen Psychiatry. 1994 Oct;51(10):794-803.
"BACKGROUND: This study examined the effect of long-term (mean, 19 months) treatment with clomipramine hydrochloride on cerebrospinal fluid (CSF) levels of several neuropeptides and monoamine metabolites in children and adolescents with obsessive-compulsive disorder. METHODS: The CSF levels of corticotropin-releasing hormone, vasopressin, somatostatin, and oxytocin and of the monoamine metabolites 5-hydroxyindoleacetic acid, homovanillic acid, and 3-methoxy-4-hydroxyphenylglycol were measured in 17 children and adolescents with obsessive-compulsive disorder before and after long-term treatment with clomipramine. RESULTS: Treatment resulted in significant decreases in CSF levels of corticotropin-releasing hormone (mean +/- SD, 175 +/- 32 vs 152 +/- 25 pmol/L, P < .03) and vasopressin (mean +/- SD, 1.30 +/- 0.57 vs 0.86 +/- 0.54 pmol/L, P < .02) and a trend toward a decrease in somatostatin levels (mean +/- SD, 21.3 +/- 8.5 vs 15.3 +/- 9.8 pmol/L, P < .06). Treatment also significantly increased CSF oxytocin levels (mean +/- SD, 6.05 +/- 1.60 vs 6.70 +/- 1.44 pmol/L, P < .01). Significant changes in CSF monoamine metabolite levels with treatment included significant decreases in CSF levels of 5-hydroxyindoleacetic acid (mean +/- SD, 109 +/- 31 vs 77 +/- 23 pmol/mL, P < .001), CSF homovanillic acid (mean +/- SD, 273 +/- 111 vs 237 +/- 101 pmol/mL, P < .04), and 3-methoxy-4-hydroxyphenylglycol (mean +/- SD, 42.4 +/- 10.2 vs 36.1 +/- 4.8 pmol/L, P < .02) and a significant increase in the homovanillic acid-5-hydroxyindoleacetic acid ratio (mean +/- SD, 2.44 +/- 0.46 vs 3.42 +/- 0.84, P < .0001). CONCLUSIONS: These neuropeptide results coupled with evidence that central administration of corticotropin-releasing hormone, vasopressin, and somatostatin to laboratory animals increases arousal and acquisition of conditioned behaviors whereas central administration of oxytocin has opposite behavioral effects are consistent with a role for these neuropeptides in the pathophysiologic processes and pharmacologic treatment of obsessive-compulsive disorder." [Abstract]

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Recent Obsessive-Compulsive and Somatostatin Research

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10) Chang CL, Chen CS, Yeung TC, Hsu ML
Biomechanical effect of a zirconia dental implant-crown system: a three-dimensional finite element analysis.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):e49-57.
Purpose: The objective of this study was to analyze and compare the stresses in two different bone-implant interface conditions in anisotropic three-dimensional finite element models (FEMs) of an osseointegrated implant of either commercially pure titanium or yttrium-partially stabilized zirconia (Y-PSZ) in combination with different superstructures (gold alloy or Y-PSZ crown) in the posterior maxilla. Materials and Methods: Three-dimensional FEMs were created of a first molar section of the maxilla into which was embedded an implant, connected to an abutment and superstructure, using commercial software. Two versions of the FEM were constructed; these allowed varying assignment of properties (either a bonded and or a contact interface), so that all experimental variables could be investigated in eight groups. Compact and cancellous bone were modeled as fully orthotropic and transversely isotropic, respectively. Oblique (200-N vertical and 40-N horizontal) occlusal loading was applied at the central and distal fossae of the crown. Results: Maximum von Mises and compressive stresses in the compact bone in the two interfaces were lower in the zirconia implant groups than in the titanium implant groups. A similar pattern of stress distribution in cancellous bone was observed, not only on the palatal side of the platform but also in the apical area of both types of implants. Conclusion: The biomechanical parameters of the new zirconia implant generated a performance similar to that of the titanium implant in terms of displacement, stresses on the implant, and the bone-implant interface; therefore, it may be a viable alternative, especially for esthetic regions. [PubMed Citation] [Order full text from Infotrieve]


11) Chou HY, Romanos G, Muftu A, Muftu S
Peri-implant Bone Remodeling Around an Extraction Socket: Predictions of Bone Maintenance by Finite Element Method.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):e39-48.
Purpose: The aim of this study was to investigate peri-implant bone remodeling as a response to biomechanical factors, including implant size and contour, magnitude of occlusal load, and properties of osteogenic bone grafts through the use of a computational algorithm. Materials and Methods: A bone-remodeling algorithm was incorporated into the finite element method, where bone remodeling takes place as a result of the biomechanical alteration caused by dental implant placement and continues until the difference between the homeostatic state and the altered state is minimized. The site-specific homeostatic state was based on a model consisting of a natural tooth. Three long (11-mm) implants and two short (5-mm) implants were investigated. A three-dimensional segment of the mandible was constructed from a computed tomographic image of the premolar region, and an extraction socket was filled with bone graft. Results: Generally, the extent of bone loss in the cortical region was greater and denser bone developed at both the implant crest and apex with increased occlusal loads. The areas between implant threads were prone to bone resorption. Bone graft materials that were relatively stiff and that had high equilibrium stimulus values appeared to cause increased bone loss. Conclusions: Short implants are better for conserving the mechanotransductive signaling environment of the natural tooth than long implants. Also, short implants are predicted to lead to less interfacial bone loss at high loads over the long term, while long implants are associated with a more consistent level of bone loss for different amounts of loading. It is also predicted that in the long term, bone grafts with relatively low elastic modulus lead to lower levels of interfacial bone loss. [PubMed Citation] [Order full text from Infotrieve]


12) Barewal RM, Stanford C, Weesner TC
A randomized controlled clinical trial comparing the effects of three loading protocols on dental implant stability.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):945-56.
Purpose: The primary goal of this stratified randomized controlled trial (SRCT) was to compare the stability of dental implants placed under three different loading regimens during the first 16 weeks of healing following implant placement. Implants were loaded immediately, early (6 weeks), or with conventional/delayed timing (12 weeks). Secondary outcomes were to compare marginal bone adaptation for 3 years after placement. Materials and Methods: Single posterior implant sites in the maxilla or mandible were examined. The insertion torque value was the primary determinant of load assignment. Resonance frequency analysis was performed at follow-up appointments for the first 16 weeks (with results provided as implant stability quotients [ISQs]). Marginal bone levels were assessed via radiographs. Results: Forty patients each received a single 4.0-mm diameter dental implant between 2004 and 2007. One implant failure occurred in Lekholm and Zarb type 4 bone with insertion torque value (ITV) of < 8.1 Ncm; the cumulative success rate was 97.5%. All implants, when classified by bone and loading type, increased in stability over time, with a minor reduction of 1.3 ISQ units seen at 4 weeks in the immediate loading group. The mean marginal bone loss over 3 years was 0.22 mm. The mean ITVs at implant placement for bone types 1 and 2 (grouped together), 3, and 4 were 32, 17, and 10, respectively, and were significantly different (P < .05). Conclusions: ITV was a good objective measure of bone type. Using an ITV of 20 Ncm as the determinant for immediate loading and an ITV of 10 Ncm or greater as the determinant for early loading provided long-term success for this implant and led to no negative changes in tissue response. All bone type groups and loading groups showed no reduction in stability during the first 4 months of healing. [PubMed Citation] [Order full text from Infotrieve]


13) Camargos Gde V, do Prado CJ, das Neves FD, Sartori IA
Clinical outcomes of single dental implants with external connections: results after 2 to 13 years.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):935-44.
Purpose: The aim of this retrospective study was to evaluate the long-term survival rates and the frequency of complications associated with single implants and their associated restorations. Materials and Methods: A retrospective cohort study was performed in patients who received dental implants between 1997 and 2007. The cohort included patients who had a single implant restored with a cemented or screwed restoration that had been in function for more than 2 years. The cumulative implant survival rates and peri-implant conditions (marginal bone loss, pocket depth, and plaque, gingival, and bleeding indices), as well as prosthodontic maintenance requirements, were evaluated. Descriptive statistics, the chi-square test, and regression models were used. Results: Seventy-three implants were placed in 44 patients (32 women, 12 men; mean age, 48 years). All implants were available for follow-up after 2 to 13 years (mean follow-up, 60 months). The overall cumulative 5-year survival rates for implants were 95.9%, and most of the prostheses (98.6%) remained functional throughout the observation period. The overall frequency of complications was 29.6% (4.3% inflammatory, 22.5% prosthetic, 2.8% operative). The average peri-implant marginal bone loss was 1.8 mm. Peri-implant soft tissue conditions such as plaque and bleeding indices and pocket depths were also satisfactory. However, the presence of inflammation was significantly associated with pocket depth and gingival keratinized mucosa. The need to retighten loose abutment screws (21%) was the most frequent prosthodontic maintenance performed. However, all loose abutment screws occurred in prostheses retained with titanium screws, and 92.9% of the prostheses had a UCLA-type abutment. Conclusion: The implants and the associated prosthetic constructions used in this study showed excellent survival rates. However, there was a high frequency of prosthetic complications associated with titanium screws and UCLA cast abutments. Other prosthetic components may have yielded different results. [PubMed Citation] [Order full text from Infotrieve]


14) Canullo L, Rosa JC, Pinto VS, Francischone CE, Gotz W
Inward-Inclined Implant Platform for the Amplified Platform-Switching Concept: 18-Month Follow-up Report of a Prospective Randomized Matched-Pair Controlled Trial.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):927-34.
Purpose: This prospective randomized matched-pair controlled trial aimed to evaluate marginal bone levels and soft tissue alterations at implants restored according to the platform-switching concept with a new inwardinclined platform and compare them with external-hexagon implants. Materials and Methods: Traditional external-hexagon (control group) implants and inward-inclined platform implants (test group), all with the same implant body geometry and 13 mm in length, were inserted in a standardized manner in the posterior maxillae of 40 patients. Radiographic bone levels were measured by two independent examiners after 6, 12, and 18 months of prosthetic loading. Buccal soft tissue height was measured at the time of abutment connection and 18 months later. Results: After 18 months of loading, all 80 implants were clinically osseointegrated in the 40 participating patients. Radiographic evaluation showed mean bone losses of 0.5 0.1 mm (range, 0.3 to 0.7 mm) and 1.6 0.3 mm (range, 1.1 to 2.2 mm) for test and control implants, respectively. Soft tissue height showed a significant mean decrease of 2.4 mm in the control group, compared to 0.6 mm around the test implants. Conclusions: After 18 months, significantly greater bone loss was observed at implants restored according to the conventional external-hexagon protocol compared to the platform-switching concept. In addition, decreased soft tissue height was associated with the external-hexagon implants versus the platformswitched implants. [PubMed Citation] [Order full text from Infotrieve]


15) Zhen F, Fang W, Jing S, Zuolin W
The use of a piezoelectric ultrasonic osteotome for internal sinus elevation: a retrospective analysis of clinical results.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):920-6.
Purpose: To explore the possibility and evaluate the clinical outcome of accomplishing maxillary internal sinus floor augmentation through the use of a piezoelectric osteotome in conjunction with dental implant placement and to discuss this technique. Materials and Methods: Patients attending the outpatient clinic of the Department of Dental Implantology, Hospital of Stomatology, Tongji University, between July 2007 and September 2009, who had insufficient bone volume to harbor endosseous implants at least 8 mm long in the lateral/posterior maxilla because of sinus pneumatization were enrolled in the study. Sinus augmentations were accomplished with a piezoelectric osteotome, followed by implant placement, either immediately or delayed (6 months after augmentation, if the residual ridge height was less than 4 mm). Results: Thirty patients with 36 maxillary molar sites with insufficient alveolar bone height as a result of pneumatization of the sinus were included in this study. The residual vertical bone height ranged from 2 to 8 mm. Twenty-eight implants were placed into 24 patients immediately after sinus augmentation. Another eight implants were placed into 6 patients 6 months after sinus augmentation. Only one sinus membrane perforated (failure rate: 2.78%). Only one implant was lost during the observation period. No other implant mobility or rapid bone loss was seen during a follow-up period of 5 to 27 months. Conclusions: Application of a piezoelectric osteotome for internal sinus elevation simplified manipulation of the membrane and greatly reduced the chance of perforation. The pressure gradient between sinus and implant cavity was helpful in accomplishing this technique. [PubMed Citation] [Order full text from Infotrieve]


16) Scala R, Cucchi A, Ghensi P, Vartolo F
Clinical evaluation of satisfaction in patients rehabilitated with an immediately loaded implant-supported prosthesis: a controlled prospective study.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):911-9.
Purpose: The purpose of this controlled prospective study was to compare the satisfaction of patients rehabilitated with an immediately loaded implant-supported prosthesis and patients rehabilitated with a conventional denture in the mandible. Materials and Methods: Selected mandibular partially or totally edentulous patients were included in this prospective study. Patients' mandibles were completely rehabilitated with immediately loaded implants supporting a screw-retained full-arch prosthesis (test group) or with a conventional denture (control group). The Satisfaction Profile (SAT-P), which investigates a number of psychologic aspects related to the function and esthetics of the stomatognathic apparatus, was administered to each patient 1 month before and 3 months after provisional prosthetic rehabilitation. The questionnaire comprised four different SAT-P items: quality of eating, eating behavior, mood, and self-confidence. A visual analog scale was used to elicit patient responses. SAT-P item scores were analyzed statistically by means of the Student t test and the chi-square test (or the Mann-Whitney nonparametric test), with P < .05 considered significant. Results: Forty-one patients were consecutively treated with 205 immediately loaded implants supporting a screw-retained full-arch prosthesis (test group); 38 patients were consecutively treated with a conventional denture (control group). Statistically significant differences were observed between the test and control groups for all four SAT-P items. The test group reported greater satisfaction for all items versus the control group. In both groups, the differences between pre- and postrehabilitation values were statistically significant. Conclusions: Each patient was satisfied with their treatment outcomes, but patients who received an implant-supported prosthesis were more satisfied than the patients who received a conventional denture. The results suggest that a screw-retained full-arch prosthesis on immediately loaded implants is a predictable means of enhancing patient satisfaction. [PubMed Citation] [Order full text from Infotrieve]


17) de Moraes EJ
The buccal fat pad flap: an option to prevent and treat complications regarding complex zygomatic implant surgery. Preliminary report.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):905-10.
Purpose: To evaluate the use of the buccal fat pad flap (BFPF) technique as an option to prevent complications in the treatment of patients with atrophic maxillae rehabilitated after complex zygomatic implant surgery. Materials and Methods: A retrospective study was made of completely edentulous patients submitted to zygomatic implant surgery between May 2005 and November 2007. Patients with severely atrophic maxillae received conventional and zygomatic implants and were followed after the implants were loaded. Preoperative evaluation included panoramic radiography and computed tomographic scans of the maxilla to identify the anatomic conditions and presence of pathology. Results: Eight male patients with a mean age of 57 years and atrophic maxillae were rehabilitated with zygomatic implants placed using the BFPF technique. The BFPF technique was used in complex situations, including oroantral communication-associated sites, areas that had lost the sinus wall, and extrasinus implant placement. A total of 16 conventional implants, 4 long (21-mm) tilted implants, and 22 zygomatic implants was placed. The patients were rehabilitated with fixed prostheses and were followed for a minimum of 15 months. None of the conventional implants failed and none of the zygomatic implants failed or presented with soft tissue complications. Conclusion: The BFPF presented a high success rate, demonstrating that it is a viable and predictable treatment option to prevent and treat soft tissue complications in complex zygomatic implant surgery. [PubMed Citation] [Order full text from Infotrieve]


18) Hsu YT, Fu JH, Al-Hezaimi K, Wang HL
Biomechanical implant treatment complications: a systematic review of clinical studies of implants with at least 1 year of functional loading.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):894-904.
Purpose: The aim of this article is to discuss the current literature available on the etiology and management of biomechanical complications of dental implant treatment. Materials and Methods: An electronic search of the PubMed database for English-language articles published before May 31, 2011, was performed based on a focus question: "How can biomechanical implant treatment complications be managed and identified?" The key words used were "dental implant," "etiology," "management," "excessive occlusal forces," "occlusal forces," "occlusion," "parafunctional habits," "biomechanical failure," "biomechanical complications," and "occlusal overloading." Clinical trials with a minimum of 10 implants followed for at least 1 year after functional loading were included. Results: The initial electronic search identified 2,087 publications, most of which were eliminated, as they were animal studies, finite element analyses, bench-top studies, case reports, and literature reviews. After the titles, abstracts, and full text of 39 potentially eligible publications were reviewed, 15 studies were found to fulfill the inclusion criteria. Conclusion: Occlusal overloading was thought to be the primary etiologic factor in biomechanical implant treatment complications, which commonly included marginal bone loss, fracture of resin/ceramic veneers and porcelain, retention device or denture base fracture of implant-supported overdentures, loosening or fracture of abutment screws, and even implant failure. Occlusal overloading was positively associated with parafunctional habits such as bruxism. An appreciation of the intricacy of implant occlusion would allow clinicians to take a more preventive approach when performing implant treatment planning, as avoidance of implant overloading helps to ensure the long-term stability of implant-supported prostheses. [PubMed Citation] [Order full text from Infotrieve]


19) Chai J, Chau AC, Chu FC, Chow TW
Correlation between dental implant insertion torque and mandibular alveolar bone density in osteopenic and osteoporotic subjects.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):888-93.
Purpose: Osteoporotic patients require particular attention during implant placement, and insertion torque (IT) has been established as a simple and noninvasive method to assess local bone quality and primary implant stability. This study aimed to test the hypothesis that IT was not significantly correlated with bone density, as assessed with computed tomography, in a group of osteopenic and osteoporotic patients. In addition, the hypothesis that IT was not significantly correlated with implant length was tested. Materials and Methods: Fifty-three completely edentulous patients with compromised bone mineral density (osteoporotic or osteopenic) who required treatment with complete maxillary dentures and complete mandibular implantsupported overdentures participated in the study. Each patient received two screw-shaped self-tapping implants (Branemark Mark III TiUnite) at the mandibular canine regions. The IT of each implant during placement was recorded. The Pearson correlation between IT and implant site bone density (Hounsfield unit) obtained from presurgical computed tomographic scans was analyzed. The relationship between IT and implant length was also studied. Results: IT was significantly correlated to implant site bone density but not to implant length. Conclusion: IT can be a viable and practical means to assess mandibular bone quality in patients with compromised general bone density. [PubMed Citation] [Order full text from Infotrieve]


20) Alsamak S, Gkantidis N, Bitsanis E, Christou P
Assessment of Potential Orthodontic Mini-implant Insertion Sites Based on Anatomical Hard Tissue Parameters: A Systematic Review.
Int J Oral Maxillofac Implants. 2012 Jul;27(4):875-87.
Purpose: To estimate the applicability of potential sites for insertion of orthodontic mini-implants (OMIs) by a systematic review of studies that used computed tomography (CT) or cone beam CT to evaluate anatomical bone quality and quantity parameters, such as bone thickness, available space, and bone density. Materials and Methods: Medline and the Cochrane Database of Systematic Reviews were searched to identify all relevant papers. Several key words were used, such as computerized/computed tomography, mini-implants, and OMIs. The anatomical variables that were assigned in each article to a specific site suggesting it as the ideal or best alternative were assessed separately and evaluated with a scoring system. Results: Twenty-two articles were included in the study. The most favorable areas for OMI insertion in the maxilla are proposed between the first and second molars buccally and palatally. The best area in the mandible is also between the first and second molars, both buccally and lingually. In the palate, the paramedian area 3 to 6 mm posterior to and 2 to 9 mm lateral to the incisive foramen was identified as the best site for OMI placement. Conclusions: Despite the heterogeneity of the studies, there was considerable agreement regarding the optimal site for OMI insertion among most studies that investigated anatomical hard tissue parameters based on CT or CBCT data. In this respect, the posterior area from the second premolar to the second molar is the best option for OMI placement in alveolar bone. [PubMed Citation] [Order full text from Infotrieve]