田害!国TreatmentDr.

concept

Ch「istianofDr.」ean-Pier「eRichelme

Garde容la(prosthodon亡ist),)大きな組織欠損を修正するために、自家骨とGeist=chBio-Oss⑪を混ぜて、インプラント周囲欠損を充填すること。

〉下顎切歯の抜歯術は上顎切歯の抜歯にも有効なテクニックである。
>早期インプラント埋入。

(SurgeOn)

Marse冊e,andFrance

①\寸08三〇蚕小ヽ細/◎Geistiich

[監修]

築山鉄平
匪療法大 雄之会 つきやま歯科医院 勤務
米国歯周病学会ボード認定 歯周病専門医
タフツ大学歯周病科 非鴬勘助教(Assistant p「ofesso「)Geis軸chBiomateriaIs

PharmaBusiness

Unit

CH-6110

WoihusenPhone十4141

AG

Biomaterials

492与6う0

fax+41414925639
WWW.geistiichヤharma.com

Treatmentconcepts

forDr.

Sahm

Pro亀Dr.JuergenNa巾aand

Per日mp漢antitis

byPD

Dr・Frank

Schwarz

BeckerrDuesseidorf;

Germany

粉骨内欠損と歯槽宮上欠損コンポーネントに対する治療戦術。
菩治療のステップ:感染除去、インプラント形成、骨造成/
GBRによって良好な結果を提供することができる。

〉ガイストリツヒ・バイオオス、ガイストリツヒ・バイオガイド、

ガイストリツヒ・ミューコグラフトは軟組織密生の治療コンセプトの重要な要素である。

ヽ容/

N○○しこ.〇m寸示

ば〇回④Geis輔ch

[監修]

築山鉄平
医療法大 雄之会 つきやま歯科医院 勤務
米国歯周病学会ボード認定 薗周病専門医
タフツ大学歯周病科 非萬勘助教(Assistant p「ofessor)

Geき虹日昌C罪
BiomateriaIs

PharmaBusiness

Unjt

CH葛6110

WoihusenPhone十4141AG

Biomaterials

492与630

fax+41414925639
WWW.geis出ch-Pharma.com

o\さ8>.乙寸m﹁小郎睦脂抽脂艦艇r鋼鱒$andCo「te=in畔&tonett!,M.S.

Cortel帖i

TonettiMS.

P,

Cortel帖P.

Cortei臨,「0ReconstructiveP-,

Carnevale,intrabony(2OOO).

(2OO5).

C冊cal

surgery: ape「iodontalG.,

Sanz,M.

&performance

Tonetti,M.S.

defects:ofa

cha=enge(「998).

guidedtissuefor

modem

Treatme[tOffor血rabony

periodontoIogy言nt
and sha=ow

deep

Penodontics

corte帖,P.,∂nd

Prato,Periodontics

andResto「ativeG.P,

P面-P「ato,Cortel帥,P.

&Tonettl

MS,

human

TonettL

Restorative

Corte=in暗,of&G.

Tonett主M.

Corte冊P;

intrab。ny

Dentistry

M.S.

NP,

defects

The

Suva可E,

56
A

w刷bio「esorbableslmP(ified

pap冊preservattom

flap.

A

barrier

fo「defectAdriaens

GTR/boneP

angle

influences

Dubravec

replacement

D,

theFonzarA・material

oroutcomeflap

alone.

tita血mLinaresA,

Tonett主M.S.,

Lang,

treatment

deepofCorte帖P,しang

pred了ctors

andTonetti

Fourmousis

comes

MS,NP,outcomes」
LN.P.,

Suvan直)intrabony

Suvan

C=nJ,

regene「ativeT。nettl

Periodo爪o1L,

TonettiMS,

P面-Prato,G.

therapyof

Zucche町G.'

defects:

C。nicalMS'

2006;

Suva時Cortellin亘r

fo=owing

AG,Rossi

m面center

二O

Cortellin暗,&P,

Vangstedoutcomes

T.・

andS"vest「i'M.'

tonetti,pinl̀Prato,G.

M.

NP,0994)・&Tonetti,M.

pinl-Prato,

Pin主Prato,

Cortel暗号&Tonetti,

cortellln時TonettC帖calco「tel臨iう4:

treatment

oftrla上Journa!

int「abonyof

C廟icaldefects.

CasePeriodonto)ogy25,

reports.

98十987lnte「natio脱(」ouma)

management of soft tissues川手egenerative procedures両ternatlOna=ourna! of

theR,

S間estri

Ross峠・,

membranes.

AJoumai

DentalM,

cont「o帖ed

Topo町Wa販∂mm

cont「o=ed
A.,of

c帖ca剛al.

Dub「avec,D.

&c臨ca廟a=ournai

Research

78,ofPeriodontoIogy

B

Zybutz

C冊Periodonto上Sep;31(9):77O-6.
P.

(2004).

(2OOT)

66,797-8O3.

(abstract).

」

Adrfaen§,M.

38「TheC陣aloutcomesslmP臨dfo冊wing

pap陸preservationt「eatmentflap

intheMcCial暗,bovinebone

mine「alorpap冊prese「vationaloneflapfortreatmento白nt「abonydefects誹radiographic

NP; European

U,しarlg

lntrabony」

defects.

Research

Cl活Periodontol.

Groupon

PeriodontoIogy

Microbial

patternpredict。f

inf「abonycoIonisation

Periodontal regeneration(1996).しOng

term

Stab航yhuman

ofc臨calfo嘉lowing

theoutcomes

defects.

Voftreatment

ofinsu「gicalE何ectoforal

tissueattachmentfo=owinggnded

regenerative(ERGOPER-O).

(2OO4).

Hea間gPOSt-OPerative

andmorbidity

patient

perception

ofout

Dec;31(12)‥1092-8.

intrabonyacasecohort.j。urnalt「eatment

hygieneonof冊rabony

longregeneration

defects.

」termancI

Periodontol.

ofPeriodontoIogydefects.

stability.

」72,

559づ69.

C冊Periodonto!

」oumalofClinicalconventiona冊erapy.

」ourna!

2OO6;

33:62

Periodonto(ogyof68.

21,606￣61O.

PeriodontoIogy

C嗣cal

23,

106￣11l.

May;75(5):672-8.

「粥轟n8Corte旧主P"ofcl涌cal

contro帖edthe35十358.

survival

軸刷erinmorbidity・ 」our棚( of Periodonto(。gy 72, 17Ol1712.

postope「ativetissue regeneration′deprote面Zed

Guided33:

B「aggerdeep

Lang

Pe「iodontology

Ma「;76(与):う41づ0.
c帖cal experience. j Periodonto上

randomizeddefects.

randomized

evaluation

Co「te冊iC冊ca!

1O4￣132.

andmemb「anesreinforcedtherapy両ntrabony

Raspe…tiFou「mousisaccess

GTRofFonzar,p,regenerative

22,ofsupp!

mu廟centersurgical approachnovel

Periodontal 「egeneratfon of huma両面abony defects with

Radiographic

with

2OO6;

defects.

2OOO

evidencesurgery」ouma)

589￣599.

tone時M言1995).

(1999).

L綱g19,

Dentj

S⊂ien描c¶ap8￣15.

(1999).

Dentistry&14,

defects:int「abonyCorte帖暗, Pin主Prato, G. & TonettL M. (「996).The modified pap冊preservation techniqueof(GTR). Pe「iodontoIogy

regeneration

regene「ative strategyaccess

G.

G.

M.

MS

TonettiTonetti,(2000).

(20O7)

Pe「iodontoIogy;

P&MSA

34:

(2OO7)

M.

(1996).

M. (1995).

&Tonetti,

Evaluation

m面ma川yPe「iodonta汗egeneration

Theof

modl轟dtheinvasive

effectsu「gicalof

huma証ntrabony

pap陸preservationof

toothtechniquev剛ty

technique.

defects

A

newoutcomesor"egenerative(MIST)

withenameinatrix

bioreso「bablewithmembranes.

A

controlledc臨caltrial.

」ournalof

Periodontoiogy67,217-223.

regeneratlVe PrOCedures. Jouma) of Periodonto!ogy 66,
surgical approach for interproximal

inintrabonylnthe(EMD)l[derivatedefects.

」ou「nal「egeneratjveoftreatme=t

C冊calofPeriodont。!ogy

intrabony

defects‥

28,

a672

679.

nOVeはpproachto帥tmorbidlty弓Oumal

87-93.

M面mally

irIVaSivesu「gic∂ltechnique(MIST)

andenamelmat「-Xderivativeintrabonydefects.

(l)

Cl面caloutcomes

andmorbidity.

JournalofC冊ical

Per10dontoIogy;「082-1088.

R.

TonettL

M,,帥一Prato,†0netti,N.P.

M.,

Corte冊,(「998).

Odontoiogy

Tonettl,&P.,

Corte冊,Suvan,

Genera"zabiwly

69,

MG.

PJ.E.,

ofC.

&(1996).

theCorte帖,Guided

Ad「iaens,addedP,P.

(1993).

Periodonta圧egeneration

tisSueregene融lOn

Bald主C.,

Dubravec,

benefitsofguidedOf

deep

D吉OnZar,tissueofintrabonyhuman

A吉OurmOSis'regeneration冊e

infrabony

defectsm

上Magnan主C.,

t「eatment

Diagno5ticdefects.

strategiea"y面portantofMuller-Campanile}

deep

int「abonyst「ate8ie§

prostheticV'

defects.

tO detectbonega叫ourna!

abutments而ternational

Pat「on主S.,

Sanz,

Eva幽onm時cente「inaM.,」ourna)

VangstedofPertodontoIogy

ofPeriOdontics

T.'「andomized64,andZaba(egu出P剛叶ato,co剛edc!証eal269￣277.

Restorative

G・t坤Ournal&しang,

ofPe「了118う-1192・Lang,

N.R,

Co「tel陣P.

Enameima廟xproteins

inthe

regenerative

ther∂PyOf

deep面abony

defects.

A

multicenteretaL(2002).

Laure=L,Corte臨時Tonettl M. Base"ne r∂dlOg「aPhic defect angle ofthe intrabony defect as a prognostic -ndicatorrandomlZedcontrolledc)inicaltria上」ourna)

ofCl面calenamelmatrix

PeriodontoIogy;29:317-25.

Tsitoura

E,

Tuckerderivative.

労Blades:}

JR,Suv∂「j,C冊Peri。donto1

2OO4;

Swam-Morton鵬,

Sutures:Gore-teX

CV-6

inregene「ativeperiodontal

surge「ywith31:643￣647.

Swa旧主Morton
P6K23ALTD,

needle

RT-

She簡eld,
13

andEngland

CV-7

and

P7K13AMicro

needle

USM

RT

69OO・

Sabielndustries,Vjsta

ー「1,W」.Gore& Ass,

FlagstaffAZ,

CA,

USA

USA

鑑の輔弼粗>Dr.

PierpaoIo

teiephone:+39

Corte帖,Via

Carlo

055

fax:

24395O,

Bott∂+3905516,5O136

Flo「ence・圃y247803l・e-ma=rstudiocortel

iini@co「te帖n主191.it◎Geis輔ch

[監修]

築山鉄平
医療法大 雄之会 つきやま歯科医院 勤務
米国歯周病学会ボード認定 歯周病専門医
タフツ大学歯周病科 非常勤勘教(Assistant p「Ofessor)

Ge百親睦師

PharmaBusiness

Unit

CH-61「0Woihusen

Phone十4141AG

BiomateriaIs

492与630

はぎ1!国T「eatment

conceptofD「.

PierpeoIo

C⑱rte輔車容ore畦e,圃y

結審美領域の歯周組織再生。
〉広汎性重度歯周炎。

ネ広汎性重度歯肉炎と広範囲なプラーク残存〉深く(「0mm)広い「壁性垣内欠損\書四削れ距毒曲①鵬配の醐鱒Regionx

aesthetic
SingieBonySoft

situation

tissueXbone

situation

non-aeSthetic

regiOntooth

defectmultipie

gapp「esentX

recessIOnX

nobonenO

reCeSSiOn

gap

defectpresent

in危ctedinflamed

X軸ckbiotype

Furtherperiodontalexamination

regiontooththin

X

prima「ywoundX

intac亡pap用aeclosureX

adequate

x

fu=

mouth

X

fu

mouth

possible

primary

wound

impaired,ke「atinised

mucosapほquescore:99%

bleeding

biotypescore:

10O%

dosuremissing

inadequate

notpossiblepap冊ekeratinised

mucosaunevent帥\ニ4

丁「ea亡me師concept

Un盲vers旺yofDr.

PascaさVa冨e雨i串⑱千Cors滝a膏rance〉ラテラルアプローチ並びに同時・待機埋人での上顎洞挙上術。
〉自家骨グラフトの回避〉轟 申隔並びに上顎洞膜の穿孔への対処

1①\の○∞○)乙.乙∞富市

Litera七ure

DeI

FabbroWa=∂CeM.,

S.,

Vaient面P.,

Ha=mann

TestoriF「oumS.;

AbensurM.,

Valent面P.,

refe「encesT.,

Francetti

Ann

Periodontol,D.;

Sennerby

Abensur

D.,

lnt」

Oral

L.,

Weinstein

R言冊」

Max用ofac而Plants,

L.,

Lundgren

S.巾t」

Wenz

B.,

M.,

Peetz

Periodontics

Restorative

De時24:565-577;2OO4

8:328-343;2OO3

OraI

Schenk

18:556-560;2003

Max用ofac 而p置∂nts, 17, PP: 63与-64う, 2002
R.;

lnt」

Periodontics

Restorative Dent

2000;20

田喜田◎Geis輔ch[監修]築山鉄平
医療法大 雄之会 つきやま歯科医院 勤務
米国歯周病学会ボード認定 歯周病専門医
タフツ大学歯周病科 非鴬勤助教(Assistant profess。r)

Ge冒虹日昌C兜Biomaterials

PharmaBusiness

UnitCH-6110

WoihusenPhone+4141

AG

Biomateriais

492

5630

fax+41414925639
WWW.geis捕ch葛Pharma.com

The「apy\J

掴輔弼輔弼購鞘のRegion

SoftBony

situation

tissuesituation

lmpiantation

conceptofProf

M=an,ltaiy>自家骨、Geist=chBio Oss⑲、Ma亡teo

Chiapasco

UniversityofGeistlichBio-Gide⑪を使った垂直的歯槽堤増生

①)①O乙さ.卜蝶富のヽノ③Geis輔ch

[監修]

築山鉄平
医療法人 雅之会 つきやま歯科医院 勤務
米国歯周病学会ボード認定 歯同病専門医
タフツ大学歯周病科 非常勤胡散(Assistant professo「)Ge冒st漢冒chBiomaterials

PharmaAGBusiness

UnitCH-6110

WoihusenPhone十41∴fax+414141492

Biomaterials

492う6う05639

WWW.geis捕ch-Pharma"COm田喜田

Treatment

concept

University,of

Dr・日stvan

Urban,

Loma

Linda

USA

?吸収性メンブレンGeist=ch

B10-Gide⑪と、自家海綿骨とGeis捕ch

Bio-Oss⑱のコンビネーショングラフトを利用した水平的歯槽堤増大術。
≫ソーセージテクニックのデモンストレーションとその説明oGeis川ch

Bio-Oss⑪は骨移植材料を安定させ、また非可動性の「ソーセージの皮」のように作用する。

\̲/帥繭輔弼棚職制黛
RegionaestheticS涌gie亡○○thBonySo什ti§Suesituation

xboneSituation

defectgap

present「eCe§S!OnX

regionm埴回egap

t○○thnobonenO「eCeSSlOn

defect涌fec蒔d

軸ck

thin

biotypebiotypeprimarywoundcIosureprimary

poss潮ewound

impaired,pap冊eadequateX

non-aeSthetic

活用amed血act

impIantation×regionkerat面§edpresent

dosuremissing

notinadequatきlくe「at証sedmucosa

uneVen帝山
s面し直aneousIy
augmentationwith(1bonestep)Xpossible

pap紺ae

SuCCeSSiveiytob〇日eaugmentation(2steps)mucosa①\き重さ.﹁﹁学乞酢自治脂抽脂一Buse「D,lngimarsson

edentulous∠UrbanAlA,

NU,

DulaInt」ovanovic」

K恒SSi

A,HirtPeriodontics

S,Lozada

study

of

35

ScharerP,

Marinello

ret「ospective

ZitzmannS,patients.

」L.

HP,Be˜ser

Resto「ativeUC工Ong-term

Dent

20O2;

Vertic∂=idge細gmentation

patients

12

CP

to72

monthsLong-term

Stab紺tyusingguidedafter ioading.冊」

reSuits

ofosseointeg「ated申ants

inaugmentedbone:inthree.c旧cal

A5-year

P「OSPeCtive

studyinpar潮y

22:109￣117.

ofimp˜ants

Oralt「eatedbone

regeneration

Max用ofacwithguided(GBR)

scena「iospriortoimplantplacement:

lmplants 2009;24:う02-う10.

boneregeneration:

A5-year

PrOSPeCtivestudy.

lnt」

Oral

Max用ofac

lmplants

2001;16:う与すう66.

4

HammerleCH帥ngconsecutive

5

U「banlA,

Nagurskybone-derived

6

RothamelRE,

cases.

D,

Yaman
Clin

H工OZadaminerai:

Schwarz

osteobIast-1ike

SchwarzF,

defectusing

D,

A

F,

C=nRidge

A,

case

HertenM,augmentation

seriesHertenOra=mplants

barrie「augmentationbyapplying

bioresorbab-emembranes

anddeprote面zed

bovinebone

mineral:withorA

repo「toftweiveanorganicbovine

2008;19:19-25.

Horizonta同dge

SculeanD,d膚erent

jL:NP.

Res

prospectiveceils.

Rothamel

LangOr∂‖mpI

M,Res.

W。stef。dmembranes:

in

22

witha

resorbablepatients, lnt」

Ora‖VIax川ofac

Scherbaum

W,Becker」・Biocompati輔ymembraneandlmplants

ofvarious

particulated

autogenous

bone

without

2Ol「;26(2)‥404-14.

collagenmembranes

incuitures

ofhuman

PDL

fibroblasts

andhuman

20O4;15(4):443つ・

M,

Sager

M,

FerrariD,

Becke申mmunohistochemica剛a「acte「izationofguidedbone

regenerationata

dehiscence-tyPe

impiants Res. 2008;19(4)‥402-1う・An experimental study in dogs. Clin Oral

鈍師瞳聡
Ant主刷ammato「ymedication:

Local

anesthetic:

Suturemateriai(ePTFE):而piant:BranemarkFixation

pins:

50

mg

diciofenac,

Artican古idrochlo「ideGORE-TEX⑪

System⑧,

Master-Pin

Nobel

System'with

cv-5

Cataflam⑪,

adrena冊e

Sutu「e,W.L.

NovartisPhamaceuticais

l/100,OOO

Gore&Associates直C.

BiocareMeisinger

鎧の師部謹)

Dr.

1stvantelephone:

Urban,Sodras

utca+363094621O3,

9,

Budapest,

Hunga「ylO26

fax:十3612OO4449,

e-ma旧stvan@implant.hu,

Website:

WWW.implant.hu〇〇回⑥Geistiich

[監修]

築山鉄平
医療法大 雄之会 つきやま歯科医院 勤務
米国歯周病学会ボード認定 歯周病専門医
タフツ大学歯周病科 非幣勤助教(Assistant p「Ofessor)

Ge童虹靴軸Biomaterials

Pha「maBusinessUnit

CH-6110WolhusenPhone十4141

AG

Biomateria漢s492与630

fax+41414925639
WWW.geistiich-Pharma.com

(Trea師e咄C⑱nCePt
師vatebyDr.

P「act盲ce,丁u「in,〉歯肉退縮被覆術。

岩歯肉バイオタイプ修正治療
少歯冠部会層弁

Danie且eIモa冒yCardaropo串①\Nささ.小し辛m」旺e聡も脚e肥千e「encesl

Wennstr6mhagen:」,

Pini

Prato

Munksgaard,G.

Mucogingival

therapy-Periodontal

plastic

surge「y.

I冊ndhe」,

Ka両g丁しangN(eds).

C帖cai

Periodonto10gy

andlmplant

Dentistry.

Copen

20O3:576￣649.

2wennstr6m

J.

Mucoginglva冊erapy.

Ann

Periodonto1

1996串671十06.

3corte冊iP

Clause「P「OCedure.

」

C,

Prato

Periodonto1

GP.

HistoIogic

assessment

HL,

Bunya「atavejP,LabadieM,

5piniA7Prato

4-yea「Tatakis

G,ClauserC,

fo=ow珂P

DN,2〇〇〇;71:

Corte冊P,Tinti

Study.

Trombe岨・」9lnt「0Gingival

Bergenholtz

S,

CafieroC,Periodontics

Amarante」

11」

the

treatment

ofa

human

buccalrecession

bymeansofa

guidedtissueregene「ationMacNe= RL.

「ecession.

C,Vincenzi

G,Comparison

1nt」

Pagliaro

of2

Periodontics

U.

c旧cai

PeriodontoI 2OOl;72:13O十1311.
techniques for t「eatment of gingivaI 「ecession. 」

Restorative

Guidedtissue

Dent

1985宰8￣13.

regeneration

versusmucogingival

surgery両hetreatmentofhumanbuccalrecessions.

recession

treatment:

Guidedtissueregeneratton

withbioabsorbablemembraneversusconnective

tissuegraf=Periodontol

299-307.

A,

Matarasso

attachmentfo冊wing

Pe「iodontoi 1996;67:1之16122う.

8

AinamoShyrY,tissue

M紺erPD.Aclass胎cationofmarginal
6

new1993;64:387￣391.

4WangofES,

LeknesPeriodonto1A,

HugosonCoraggioF,

Resto融ive
KN,

P Surgery. 」 C冊Periodontol 1992;19:49̲52AinamoJ. Location ofthe mucogingiva=unction 18 years after apica=y repositioned fla

A,

Vaia

Dent

Skavland川eT.

E,dePao-iS.

Guidedtissueregene「ationversus

corona町yrepositioned

flap

in

thetreatment

ofrecession

withdoublepap陸e'

1998笹444-453.
Corona=ypositioned

flap

procedures

withorwithout

abioabsorbablemembranein

thetreatment

ofhumangingival

recession.

Controiled

C出血a冊al冊」

2OOO;71:989-998.

Cardaropoli

D,Periodontics

Restorative

Cardaropoli

G川ea冊gDent.

2009ofGingival

Recessions

UsingaCo˜lagen

MembranewithaDeminerahed

Xenograft:A

Randomized

Feb;29(1):与9-67.

S鵬師話冒e臆>Sutures:

Resopren

5/0(Resorba,Germany)andGlycoIon

5/0(Resorba,Germany)

C①師部鳴>

Dr.

Danieie

Cardaropol主Corso

teiephone‥十39.011.323683,

Ga用eo

Ferraris148,

fax:十39.01「・323683,

lO129

Turin直aly

e-ma圧dacardar@tin-it

Website‥WWW.Carda

ropo旧t国〇回④Geis輔ch亡監修]

築山鉄平
医療法人 雅之会 つきやま歯科医院 勤務
米国歯周病学会ボード認定 歯周病専門医
タフツ大学歯周病科 非常勤助教(Assistant professor)

Ge昌親日暗証
Biomaterials

PharmaBusiness

Unit

CH葛6110

Wo旧usenAG

Biomateriais

phone十4「41fax十4「492う6う941

492う6う0

WWW.geis耶ch-Pharma.com

田喜田

Clinical師vate

Procedure

Practice,byAssoc.

Sta「nberg,P「of.

D「・

DietmarWeng・

Germany

判事乗のインプラント埋人に備え、 頬側骨欠損を伴う歯槽胃に対して行った抜歯後歯槽堤保存術(リツジフリザベーション)

。

竃害長田

=れ宙cat盲onp「⑱制eArea

aestheticXBoneSoft

situation

tissueXSingIetoothbonesituation

×regi。ndefectgap

XthickXwound

sufficientt○○thdefectgap

noboneno「ecesslOnX

prima「ywo即dpresentdosure

insu楠cient

kerat面sedth涌bio亀ype

biotypeprimary

regionm埴ipieX

p「esent

recessIOn

non-aeSthetic

dosurekerat面sed

possiblemucosanotpossible

mucosaunremarkablelmplantation

X

atthe
bone

same

time

干oilow涌gas

augmentation(1step)bone

augmentation(2steps)ue)きNミ.曾山しい

ばSウ◎Geis輔ch[監修]築山鉄平
医療法大 雄之会 つきやま歯科医院 勤務
米国歯周病学会ボード認定 歯周病専門医
タフツ大学歯周病科 非常勘助教(Assistant professor)

Gei丸さ百C門
BiomateriaI§∴

PharmaBusiness

Unit

CH-611O

Wo漢husenphone十41fax+414141492

AG

Biomaterials

492与6う05639

WWW.geis朝chapharma.com